Effects of Supplemental Feeding of Plum Juice Concentrate on Fecal Microbial 
Shedding and Pork Quality 
 
by 
 
Jordan Christie Wicks 
 
 
 
 
A thesis submitted to the Graduate Faculty of 
Auburn University 
in partial fulfillment of the 
requirements for the Degree of 
Master of Science 
 
Auburn, Alabama 
May 6, 2012 
 
 
 
 
Keywords: Pig, Pork Quality, Plum Juice Concentrate, Microbial Shedding,  
 
 
 
Copyright 2012 by Jordan Christie Wicks 
 
 
Approved by 
 
Christy L. Bratcher, Chair, Assistant Professor of Animal Sciences 
W. F. Owsley, Associate Professor of Animal Sciences 
Manpreet Singh, Associate Professor of Poultry Science
 
 
ii 
 
 
Abstract 
 
 
Purebred Yorkshire pigs (n=32) were fed at the Auburn University Swine 
Research and Education Center to determine the influence of supplementation of plum 
juice concentrate (PJC) on microbial shedding, growth, carcass, and quality 
characteristics of pork. Pigs were sorted by weight and sex (n=16 barrows, n=16 gilts) 
and assigned to a pen which housed two pigs per pen. Pens were randomly allotted to one 
of four treatment groups. Experimental diets contained 0% (Control), 0.5%, 1%, or 2.9% 
plum juice concentrate (PJC).  All basal diets consisted of corn and soybean meal 
formulated to meet or exceed National Research Council (NRC) recommendations. Pigs 
were allowed ad libitum access to feed and water, and treatment diets were formulated to 
be isocaloric.  During the feed trial, feed intake and weight gain were measured every 14 
d and fecal samples were collected directly from the anus from one pig per pen on days 0, 
1, 7, 14, 28, 56, and last day on feed(Group 1=84 d; Group 2=100 d). Pigs were harvested 
(n=2 groups) at an average pen weight of 114 kg. All pigs were swabbed near the anus to 
measure microbial load on the hide. Fecal and ham swab samples were plated and 
enumerated for anaerobic bacteria (AA) and aerobic bacteria (APC). Samples were also 
enriched to determine prevalence of Salmonella spp. and generic E.coli (VRBA). Carcass 
and quality characteristics were recorded according to National Pork Producers Council 
Guidelines (2000) 24 hr postmortem. Data were analyzed using GLM procedure and 
mixed model analysis (SAS, 2002). Pen was the experimental unit and independent fixed 
iii 
 
effects included: diet, sex, rep, and harvest group for growth, carcass, and meat quality. 
Diet and day were independent fixed effects for microbial analysis. Results indicated that 
Salmonella spp. was not present in any sample throughout the experiment, therefore no 
data are reported. Total counts for anaerobic bacteria and E.coli were not different among 
any treatment. Feeding PJC was effective in decreasing fecal bacterial populations for 
APC (P=0.03) when compared to the control. Additionally, AA (P=0.04) bacteria counts 
were different for day by treatment effect and showed a decreasing trend for treatments 
1.0% PJC and 2.9% PJC. The level of PJC did not affect growth performance or meat 
quality. Wetness was the only carcass characteristic to be affected by level of PJC 
supplement (P=0.02), The results of this study demonstrate that supplementing a PJC to 
growing / finishing pigs does decrease aerobic bacteria as well as decreases anaerobic, 
aerobic and VRBA counts from d 0 to d 14. However, these results indicate that the 
supplementation of PJC has no effect on growth, carcass, or quality characteristics of 
pork. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
iv 
 
Acknowledgments 
 
 
 Since moving to the Auburn two years ago, I have caught a lot of grief about not 
saying please and thank you enough, so to make up for lost time, here it goes. 
 First, I would like to thank Bill Bretzman, Dan Weber, Bob Beutke, Dr. Atkinson, 
and Dr. Apgar for spending countless hours coaching my judging teams, taking me to 
livestock shows, educating about animal agriculture and more than anything thank you 
for helping me find what I am truly passionate about.  
 I would like to thank my parents Rex and Jill Wicks for instilling in me a good 
work ethic, and pushing me to achieve my goals in which their endless love and support 
made it all possible. I would also like to thank my siblings Jessica, Jared, and Jenna, as 
well as my grandparents and sister-in-law Angie, for their love and encouragement 
throughout the years.  Additionally, thank you to Amanda Martin, Valerie Blaszczak, 
Laura Pratt, and Valerie Lynch for their continuous love, support, and friendship despite 
all the miles in between us.  
 I would like thank Dr. Owsley and Dr. Singh for their guidance, support, and 
enthusiasm throughout my research and graduate program.  Thank you to Mike Carroll 
and Brian Anderson in helping me with the live animal portion of my project. I would 
like to extend a big thanks to the Meat Lab crew; Susan Dale, Pete Holloway, and T. J. 
Mayfield for your willingness to always help, teach, and feed me lunch at the meat lab. 
Additionally I would like to thank Michelle Hayden and Heidi Finegan for their 
v 
 
friendship, support, and help with my project.  Furthermore, I would like to thank Dr. 
Rodning, Dr. Kriese-Anderson, Kayla Blake, Staci DeGeer, Alex Tigue and Sean Brotzge 
for their assistance in my research project.  
 I would like to thank the Department of Animal Science for truly becoming my 
?Auburn Family?. I would especially like to thank Dr. Greene for always making time to 
talk, teach and mentor me.  I would also like to especially thank Kathleen Swenson, John 
Starnes, Randa Owen, and Sam Belanger for their friendship, which has kept me from 
going insane under all the stress of graduate school. 
 I would like to thank Tabitha Welch for her help every step of the way in my 
research and graduate studies as well as her continuous love, support, encouragement, 
and invaluable friendship. Extra big thanks to Barney Wilborn, who has truly been a great 
friend, and mentor, as well as taught me a life time of knowledge. Furthermore, I would 
like to extend a big thank you to Dr. Bratcher.  Dr. Bratcher, I am truly thankful for the 
opportunities you have given me, the lessons you have taught me and the fun we have 
had. Boss, thank you for your continuous guidance, encouragement, love, and friendship 
you have shown me. Thank you for taking a chance on a student like me and helping to 
keep drawing that line in the sand.  Finally I would like to thank God, for allowing all of 
you to be a part of my life, and for that, I am forever grateful.
 
 
 
 
 
 
 
vi 
 
Table of Contents 
 
 
Abstract ......................................................................................................................................... ii 
Acknowledgments........................................................................................................................ iv  
List of Tables ............................................................................................................................. viii 
List of Figures ............................................................................................................................... x 
I. Introduction   ............................................................................................................................. 1 
II. Review of Literature  ............................................................................................................... 4 
 Pathogens of Concern   ..................................................................................................... 4 
 Pre-Harvest Food Safety   ................................................................................................. 9 
 Pre-Harvest Meat Quality   ............................................................................................. 13 
 Phenolics   ....................................................................................................................... 14 
 Conclusion   .................................................................................................................... 17 
III. Effects of Feeding Plum Juice Concentrate on Fecal Shedding in Growing / Finishing 
Pigs .................................................................................................................................. 19 
 
 Abstract   ......................................................................................................................... 19 
 Introduction   ................................................................................................................... 20 
 Materials and Methods   .................................................................................................. 22 
 Results and Discussion  .................................................................................................. 24 
 Implications  ................................................................................................................... 25
 
 
vii 
 
IV. Growth and Carcass Characteristics of Pigs Fed Plum Juice Concentrate as a Feed  
Additive  ......................................................................................................................... 26 
 Abstract   ......................................................................................................................... 26 
 Introduction   ................................................................................................................... 27 
 Materials and Methods   .................................................................................................. 28 
 Results and Discussion  .................................................................................................. 36 
 Implications  ................................................................................................................... 41 
References   ................................................................................................................................. 62 
Appendix    .................................................................................................................................. 72 
 48 Hour Drip Loss   ........................................................................................................ 72 
 Marinade Uptake   ........................................................................................................... 74 
 Marinade Cook Loss   ..................................................................................................... 75 
 Thiobarbituric Reactive Substances Assay  .................................................................... 76 
 Fatty Acid Methyl Esters  ............................................................................................... 78 
           Trained Sensory Evaluation Form  .................................................................................. 79 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
viii 
 
List of Tables 
 
 
Table 1. LS Means ? SEM for Treatment Effects of Feeding PJC to Growing / Finishing 
Pigs on Anaerobic, Aerobic, and VRBA Plate Counts ................................................... 42 
 
Table 2. LS Means ? SEM for Day Effects of Feeding PJC to Growing / Finishing Pigs 
on Anaerobic, Aerobic, and VRBA Plate Counts ........................................................... 43 
 
Table 3. Composition (as-fed basis) of Experimental Basal Diets for Growing / Finishing 
Phases .............................................................................................................................. 44 
 
Table 4. LS Means ? SEM for Treatment Effects of Feeding PJC to Growing / Finishing 
Pigs on ADFI, G:F, ADG, Finishing Live Wt, and Adj. Days 250 lbs. ......................... 45 
 
Table 5. LS Means ?  SEM for Sex and Harvest Group Effects of Feeding PJC to 
Growing / Finishing Pigs on ADFI, G:F, ADG, Finishing Live Wt., and Adj. Days 
250 lbs. ............................................................................................................................ 46 
 
Table 6. LS Means ?  SEM for Treatment Effects of Feeding PJC to Growing / Finishing 
Pigs on HCW, Dressing Percentage, LEA, Adj. LEA, Last Rib Fat, Adj. Back Fat, 
and Muscle Score ............................................................................................................ 47 
 
Table 7. LS Means ?  SEM for Treatment Effects of Feeding PJC to Growing / Finishing 
Pigs on Marbling, Wetness, Firmness, L*, a*, b*, PFFL, and FFL................................ 48 
 
Table 8. LS Means ?  SEM for Sex and Harvest Group Effects of Feeding PJC to 
Growing / Finishing Pigs on HCW, Dressing Percentage, LEA, Adj. LEA, Last 
Rib Fat, Adj. Back Fat, and Muscle Score ...................................................................... 49 
 
Table 9. LS Means ?  SEM for Sex and Harvest Group Effects of Feeding PJC to 
Growing / Finishing Pigs on Marbling, Wetness, Firmness, L*, a*, b*, PFFL, and 
FFL .................................................................................................................................. 50 
 
Table 10. LS Means ?  SEM for Treatment Effects of Feeding PJC to Growing / 
Finishing Pigs on Drip Loss, Marinade Uptake, Marinade Cook Loss, WBS, and 
Cook Loss  ...................................................................................................................... 51 
 
Table 11. LS Means ?  SEM for Sex and Harvest Group Effects of Feeding PJC to 
Growing / Finishing Pigs on Drip Loss, Marinade Uptake, Marinade Cook Loss, 
WBS, and Cook Loss  ..................................................................................................... 52
ix 
 
 
 
Table 12. LS Means ? SEM for Effects of feeding PJC to Growing / Finishing Pigs on 
Fatty Acids ...................................................................................................................... 53 
 
Table 13. LS Means ? SEM for Sex Effects of feeding PJC to Growing / Finishing Pigs 
on FA .............................................................................................................................. 54 
 
Table 14. LS Means ? SEM for Effects of Feeding PJC to Growing / Finishing Pigs on 
Initial Juiciness, Sustained  Juiciness, Initial Tenderness, Sustained Tenderness, 
Pork Flavor, and Off Flavor ............................................................................................ 55 
 
Table 15. LS Means ? SEM for Sex and Harvest Group Effects of Feeding PJC to 
Growing / Finishing Pigs on Initial Juiciness, Sustained  Juiciness, Initial 
Tenderness, Sustained Tenderness, Pork Flavor, and Off Flavor ................................... 56
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
x 
 
 
List of Figures 
 
 
Figure 1. Day x Treatment Effect of Feeding PJC to Growing / Finishing Pigs on 
Anaerobic Plate Count .................................................................................................... 57 
 
Figure 2. Day x Treatment Effect of Feeding PJC to Growing / Finishing Pigs on Aerobic 
Plate Count ...................................................................................................................... 58 
 
Figure 3. Day x Treatment Effect of Feeding PJC to Growing / Finishing Pigs on VRBA 
Count ............................................................................................................................... 59 
 
Figure 4. Effects of Feeding PJC to Growing / Finishing Pigs on Ham pH ............................... 60 
Figure 5. Effects of Feeding PJC to Growing / Finishing Pigs on Loin pH ............................... 60 
Figure 6. Sex and Harvest Group Effects of Feeding PJC to Growing / Finishing Pigs on 
Ham pH ........................................................................................................................... 61 
 
Figure 7. Sex and Harvest Group Effects of Feeding PJC to Growing / Finishing Pigs on 
Loin pH ........................................................................................................................... 61
1 
 
 
I.  INTRODUCTION 
Microbial food safety is an increasing public health concern worldwide (Zhao et 
al., 2001). The United States food supply is among the safest in the world (Oliver et al., 
2009), however, every year people die, and countless others suffer due to breaches in 
food safety (Oliver et al., 2009). The most serious meat safety issues, resulting in 
immediate consumer health problems and recalls from the market place, are from 
potentially contaminated products associated with bacterial pathogens (Sofos, 2008). 
Major causes of concern and product recalls stem from the pathogens Salmonella, and 
Escherichia coli (E.coli) 0157:H7 (Sofos, 2008). Salmonella infections are most 
commonly associated with the consumption of contaminated poultry, beef, and pork 
(Foley et al., 2008), and while cattle are thought to be the primary reservoir of E.coli 
0157:H7 (Rice et al., 2003), research has also demonstrated fecal shedding by other 
domestic livestock such as pigs (Feder et al., 2003).  
Animals can become infected by several factors; contact with other infected 
animals or pests, living in unclean facilities, consuming contaminated feed or water, or 
harboring pathogens on their hides from feces, soil or general environment (Oliver et al., 
2009). Of all of these vectors, fecal shedding is correlated highest with carcass 
contamination (Elder et al., 2000). Therefore, the most significant intervention strategy in 
reducing pathogens in meat could be implementing pre-harvest food safety hurdles at the 
production level, to help prevent fecal shedding
2 
 
 
Antibiotics are often included in pig diets to help control gastrointestinal 
pathogens by disrupting the intestinal microbial ecosystem, consequently improving food 
safety (Callaway et al., 2003). Antibiotics fed in sub-therapeutic levels however, have 
become highly controversial due to concern of antibiotic resistance in humans, and 
antibiotic-residue in animal products (Callaway et al., 2003, Schwarz et al., 2001). 
Therefore, ?natural? methods need to be researched. Fung, (unpublished data) reported 
that using a ?natural? antimicrobial in the form of a plum extract mixed in ground beef  
suppressed 90% of foodborne pathogens, including Salmonella and E. coli. 
Although food safety is of utmost concern, consumers scrutinize food more today 
than they did in the past (Troy and Kerry, 2010) and their preference is beginning to 
change to a more ?natural? label (McCarthy et al., 2001; Rhee et al., 2001). Though 
consumers pay more attention to credence qualities like safety, healthiness, convenience, 
locality, and ethical factors (Bernu?s 2003; Issanchou, 1996), consumers still take into 
consideration meat quality attributes such as; meat color, visible drip, and visible fat 
(Troy and Kerry, 2010). 
The meat industry has typically used synthetic antioxidants such as BHA and 
BHT to inhibit oxidation and improve meat quality (Chastain et al., 1992; Chen et al., 
1984; Sato & Hegarty, 1971), but with consumers becoming more concerned with 
potential toxicological effects (Decker & Mei, 1996; Rababah et al., 2004) different 
methods have been studied.
 
3 
 
 The addition of antioxidants to swine diets during the growing and finishing 
period has shown to be beneficial in the improvement of pork quality (Cannon et al., 
1996). Supplementing the antioxidant, Vitamin E in the form of ? ? tocopherol has 
shown to decrease lipid oxidation, drip loss, and improved color of pork when 
supplemented to growing / finishing pigs (Asghar et al., 1991; Monahan et al., 1990a, b, 
1992).  
Another method of improving pork quality through the use of antioxidants is post-
harvest enhancement of the product. In recent years, research has identified plums as a 
functional ingredient to not only help reduce foodborne pathogens, but to also improve 
meat quality by decreasing lipid oxidation and increasing the juiciness of meat without 
altering the flavor of the product. The indigenous chemical compounds that make up 
plums serve specific functions when applied to foods.  Pectin aids in moisture retention, 
while malic acid enhances flavor, and sorbitol acts as a natural humectant (Nu?ez de 
Gonzalez et al., 2009). These attributes have been credited for decreasing lipid oxidation, 
and warmed over flavor (WOF), as well as increasing mouth-feel, juiciness, and nutrients 
(Nunez de Gonzalez et al., 2008, Yildiz-Turp and Serdaroglu 2010, Leheska et al., 2006, 
Lee and Ahn 2005). 
Therefore, the objective of this study was to test the effect of adding an 
antioxidant in the form of plum juice concentrate to diets fed to growing / finishing pigs 
on fecal shedding, growth performance, carcass characteristics, and overall meat quality.
 
4 
 
 
II. REVIEW OF LITERATURE 
Consumers scrutinize food more now than ever in the past (Troy and Kerry, 
2010). Bernu?s (2003) and Issanchou (1996) reported that consumers pay more attention 
to credence qualities like safety, healthiness, convenience, locality, and ethical factors. 
Becker (1999) goes on to report that these attributes focus primarily on the production 
and not the product itself. Though consumers are becoming more particular with how the 
animal was raised, the healthiness of the product, and product safety; consumers still take 
into consideration meat quality attributes such as: meat color, visible drip, and visible fat 
(Troy and Kerry, 2010). Challenges to provide a safe, abundant, and nutritious product 
are complex because all aspects of food production, from farm to fork, must be 
considered (Oliver et al., 2009). With consumers becoming more educated and 
preferences changing, researchers and producers must team together in order to meet 
these demands by decreasing the risk of food-borne pathogens and increasing a high 
quality, healthy product that consumers will accept.  
Pathogens of Concern 
 Microbial food safety is an increasing public health concern worldwide (Zhao et 
al., 2001). The United States food supply is among the safest in the world (Oliver et al., 
2009), however, every year people die and countless others suffer due to breaches in 
5 
 
food safety (Oliver et al., 2009). The most serious meat safety concerns, resulting in 
immediate consumer health problems and recalls from the market place, are from 
potentially contaminated products associated with bacterial pathogens (Sofos, 2008). 
Major causes of concern and product recalls stem from the pathogens Salmonella, and 
Escherichia coli (E.coli) 0157:H7 (Sofos, 2008). 
Salmonella 
 In 1885, Salmonella species were first isolated from pork by Salmon and Smith 
(Ruben et al., 1942). Since then, 2,500 serotypes of Salmonella have been discovered 
(Foley and Lynne, 2008). Salmonella is a gram-negative rod (Coburn et al., 2007), and 
due to genetic similarity between serotypes, Salmonella has been divided into two 
species; Salmonella bongori and Salmonella enterica (Foley and Lynne, 2008), with 99% 
of all serotypes being grouped in Salmonella enterica (Brenner and McWhoter-Murlin, 
1998).  Salmonella enterica is a very common and serious foodborne pathogen, causing 
26% of all human foodborne infections, with approximately 1.3 million illnesses and over 
500 deaths annually in the United States (Mead et al., 1999). Salmonella infections also 
impact the US economy, costing an estimated 2.3 to 3.6 billion dollars annually due to 
loss of work, medical care, and loss of life (Buzby et al., 1996; Frenzen et al., 1999).  
Salmonella infections are most commonly associated with the consumption of 
contaminated poultry, beef, and pork (Foley et al., 2008).  Many foodborne pathogens, 
including Salmonella enterica typically harbor in pigs? gastrointestinal tracts, farm 
environment, and on the skin of pigs (McEwen and Fedorka-Cray, 2002). Pigs can 
become infected with Salmonella enterica through breeder herds, contaminated feed and 
6 
 
water, and most commonly, fecal waste (Bailey, 1993). It has also been reported that pigs 
can become infected with Salmonella through their respiratory system and tonsils 
(deJong and Ekdahl, 1965), allowing other locations of the pig?s body to become infected 
by hematogenous or lymphatogenous spread (Fedorka-Cray et al., 1995). Salmonella 
entering via the fecal-oral route has evolved to be able to withstand and survive a pig?s 
stomach antimicrobial defense of a low pH (Foley and Lynne, 2008). Once in the 
stomach of the animal, Salmonella is able to colonize and spread to the small intestine 
and colon, attaching to the intestine by pili present on the bacterial cell surface (Foley and 
Lynne, 2008). Though pigs are known to have Salmonella colonies in their 
gastrointestinal tract (Davies, et al., 1999), they do not show any symptoms of being ill 
(Callaway, et al., 2007), and are a primary vectors for transmitting Salmonella to humans 
(Borland, 1975).  
 The primary route for humans to become infected with Salmonella is through 
fecal-oral transmission (Foley and Lynn, 2008). The number of cells needed to make a 
human ill ranges from as low as 30 cells to as high as 109 cells depending on the serotype 
(Morgan et al., 1994). Salmonella can manifest in humans in different forms including; 
gastroenteritis, bacteremia, typhoid fever, and focal infections (Darwin, and Miller, 
1999). Of these forms, gastroenteritis is most common when consuming Salmonella 
enterica contaminated pork, and causes victims to experience diarrhea, abdominal 
cramps, vomiting, and fever (CDC, 2001). Gastroenteritis symptoms develop within 6 to 
72 h after ingestion of bacteria and signs typically last 2 to 7 d, with rare cases causing 
septicemia and invasive infections of organs and tissues (CDC, 2001; Cohen et al., 1987).  
E.coli 
7 
 
 Like Salmonella, E. coli is another harmful pathogen that is commonly found in 
the food supply. E. coli is a gram-negative rod that was first identified as a food-borne 
pathogen in 1982, after two outbreaks of hemorrhagic colitis were linked to eating 
contaminated ground beef (Riley et al., 1983). Shiga toxin-producing E. coli (STEC) 
0157:H7 is the most prominent STEC and causes numerous outbreaks of food-borne 
diseases worldwide (Meng et al., 2001). E. coli 0157:H7 is estimated to cause an average 
of 500 outbreaks, affecting more than 73,000 people and killing 61 people each year in 
the United States (Mead et al., 1999). Though E. coli 0157:H7 is the most recognized, 
over 200 other E. coli serotypes exist and over 100 strains have been associated with 
human illnesses (Nataro and Kaper, 1998).  
Cattle are thought to be the primary reservoir of E.coli 0157:H7 (Rice et al., 
2003), but research has also demonstrated fecal shedding by other domestic livestock 
such as pigs (Feder et al., 2003). Pigs can become infected with E.coli 0157:H7 by 
ingesting bacteria through contaminated feed and water, followed by fecal shedding of 
the pathogen that, in turn contaminates the farm environment, causing new infections and 
reinfections of animals both in the gastrointestinal tract and on the hide of the animal 
(Oliver et al., 2009). Though STEC infects the pig by producing toxins in the 
gastrointestinal tract, the pig will show no clinical signs of being sick (The Center for 
Food Security and Public Health, 2006). This allows infected animals to be harvested and 
equipment or human error in the harvesting process may potentially contaminate 
carcasses consumers will eat. Another way consumers can be affected by contamination 
is through the application of manure, as a fertilizer, to a field of produce (McEwen and 
Fedorka-Cray, 2002). Research has demonstrated the long-term survival of E.coli 
8 
 
0157:H7 in manure held under a variety of conditions, so even treated waste could still be 
a vector of contamination to raw produce (Kuda et al., 1998; Wang et al., 1996).  
Consumers become infected with E. coli 0157:H7 through eating contaminated 
product which can lead to serious illness or even death. Humans can become ill with E. 
coli 0157:H7 by ingesting as little as 10 cells (Armstrong et al., 1996). Illness caused by 
E.coli 0157:H7 can be expressed as three different manifestations; hemorrhagic colitis, 
hemolytic uremic syndrome (HUS), or thrombotic thrombocytopenic purpura (TTP) 
(Doyle and Padhye, 1989; Griffin et al., 1988). Hemorrhagic colitis onset ranges 3 to 9 d 
after consuming cells and last 2 to 9 d (Doyle, 1991). Symptoms of hemorrhagic colitis 
consist of sudden and severe abdominal cramping, followed by bloody diarrhea (Doyle, 
1991). HUS begins with bloody diarrhea and can also lead to hemolytic anemia, 
thrombocytopenia (low circulating platelets), or kidney disorder (Doyle, 1991). 
Individuals with HUS often require dialysis and blood transfusions, and may also suffer 
from seizures or comas (Doyle, 1991). Some of the symptoms of TTP may exhibit similar 
to those of HUS, but typically the central nervous system is attacked, leading to blood 
clots in the brain and usually resulting in death (Doyle, 1991). 
  Pork consumption has increased 20% in the last century (Buzby and Farah, 
2006), and with increase in consumption comes potential increase of Salmonella and 
E.coli foodborne illness for consumers (Foley and Lynne, 2008). Because Salmonella and 
E.coli can live undetected in pigs (Callaway et al., 2008), be present prior to entering a 
processing facility, and are known to be found on pork carcasses through cross 
contamination in processing plants (Foley et al., 2008), food safety hurdles must be 
implemented and tailored to specific livestock species while still being applicable to large 
9 
 
numbers of animals (Callaway et al., 2008). Food producers have a moral and ethical 
responsibility to produce the safest food for consumers (Rollin, 2006). One area that 
could contribute to the reduction of Salmonella and E.coli contaminated meat is on-farm 
pre-harvest food safety (Foley et al., 2008).  
Pre-Harvest Food Safety  
Traditionally, food safety research has targeted improvements in post-harvest 
sanitation and safety in meat (Elder et al., 2000). Recently researchers have begun to 
stress the importance of intervention strategies in live animal production, by developing 
new technologies for pre-harvest food safety in meat (Callaway et al., 2003). Some pre-
harvest pathogen control techniques that have been explored include; diet manipulation, 
use of feed additives, antibiotics, bacteriophage therapy, immunizations, competitive 
exclusion, prebiotics, probiotics, and proper animal management such as pen 
management, clean feed, chlorinated water, and little to no stress during transportation 
(Sofos, 2004a, 2004b, 2005; Stopforth & Sofos, 2006). Animals can become infected by 
several factors; contact with other infected animals or pests, living in unclean facilities, 
consuming contaminated feed or water, or harboring pathogens on their hides from feces, 
soil or general environment (Oliver et al., 2009). Of all of these vectors, fecal shedding is 
correlated highest with carcass contamination (Elder et al., 2000). Therefore, the most 
significant intervention strategy in reducing pathogens in meat could be implementing 
pre-harvest food safety hurdles at the production level, such as supplementation of 
antibiotics and antimicrobials in the feed, to help reduce foodborne pathogenic bacterial 
populations in the gut and on the hide of pigs prior to slaughter (Hynes and Wachsmuth, 
2000). 
10 
 
Antibiotics  
Antibiotics are often included in pig diets to help control gastrointestinal 
pathogens by disrupting the intestinal microbial ecosystem, consequently improving food 
safety (Callaway et al., 2003). Antibiotics have also been supplemented in sub-
therapeutic levels to improve growth performance and feed efficiency since the 1950?s 
(Kiser, 1976). Antibiotics fed in sub-therapeutic levels however, have become highly 
controversial due to concern of antibiotic resistance in humans, and antibiotic-residue in 
animal products (Callaway et al., 2003, Schwarz et al., 2001). Specific concerns of 
antibiotic resistance include: the potential for higher risk of infection in humans during 
treatment with antibiotics, the potential for failure of human antibiotics in treating of 
infections, increased severity of illness caused by antibiotic resistant pathogens, and 
potential for co-selection of higher virulence genes (Institute of Food Technologist, 
2006). Due to these concerns, the European Commission (EC) has prohibited the use of 
antibiotic feed additives as growth promoters in pig production since January 2006 in the 
European Union (European Commission, 2003). As a consequence of the ban from the 
EC the US cannot export pork that has been supplemented with antibiotics for 
consumption in the European Union. With regulatory pressure and rising consumer 
concern, alternative strategies must be researched and implemented to continue to create 
a safe and efficient product for both consumers, and producers (Bae et al., 1999). 
Antimicrobials  
 One alternative to supplementing antibiotics in swine diets is by supplementing 
different forms of antimicrobials into the diet. By adding antimicrobials to feed or water, 
11 
 
pigs still receive the benefit of antibiotics by inhibiting of the growth of pathogens, but 
not the negative publicity of antibiotics. Whitney et al. (2006) supplemented an 
antimicrobial in the form of bacitracin methylene disalicylate, to growing pigs to reduce 
or inhibit intestinal lesions caused by the pathogen Lawsonia intracellularis. Another 
example of supplementing antimicrobials into swine diets is the use of  a potato (Solanum 
tuberosum L. cv. Gogu Valley) protein to reduce bacterial populations in feces of 
weanling pigs (Jin et al., 2008).  
 The study conducted by Whitney et al. (2006) tested the effect of including 10% 
of distiller dried grains with solubles (DDGS), and also tested the inclusion of an 
antimicrobial, bacitracin methylene disalicylate, in the diet of growing pigs to determine 
the reduction or inhibition of growth of intestinal lesions when inoculated with Lawsonia 
intracellularis. One hundred 17 d old pigs were randomly allotted to one of five 
treatments; negative control, corn-soy diet, not inoculated (NC);  positive control, corn-
soy diet, inoculated (PC);  10% DDGS diet, inoculated (D);  positive control, with 
antimicrobial supplementation, inoculated (PC + A);  and 10% DDGS diet, with 
antimicrobial supplementation, inoculated (D + A). DDGS have shown to reduce the 
spread of pathogenic organisms in the intestine (Hampson et al., 1999) due to fiber 
influence. Fiber can stimulate secretion of the epithelium, impairing bacterial adhesion 
(Smith and Halls, 1968). Results were that pigs fed diets containing antimicrobial 
supplementation had a lower occurrence of lesions in the jejunum and tended to have 
reduced total tract lesion length. Likewise, pigs fed D + A had reduced fecal shedding of 
Lawsonia intracellularis, determining supplementation of DDGS and antimicrobial is 
beneficial in reducing pathogens in the gastrointestinal tract and feces of pigs.  
12 
 
 The study conducted by Jin et al. (2008) used 280 weaned pigs (Landrace X 
Yorkshire X Duroc) in a 28 d feeding period to examine the effect of supplementing an 
antimicrobial peptide in the form of  potato protein (PP) as an antibiotic replacer to 
decrease the level of bacteria in the feces.  Pigs were randomly assigned to one of five 
treatments: a positive control, a basal diet with antibiotics (PC) and 4 potato protein diets, 
which consisted of a basal diet supplemented with 0%, .25%, .50%, or .75% PP.  Diets 
were fed for 28 d, and body weight and feed disappearance were measured every two 
weeks.  Fecal samples were collected on days 0, 7, 14, 21, and 28 to determine levels of 
bacteria present in feces.  The conclusion was that supplementing swine diets with PP, 
reduced bacterial counts in the feces and improved ADG, ADFI, and G: F, which 
demonstrated that PP was a useful alternative to antibiotic supplementation.  
 Although, supplementing natural antimicrobials in swine diets does reduce 
pathogens and overall bacteria in feces, it does not completely eliminate all microbes that 
could potentially harm the food supply. Ayres (1955) stated the origin of microflora are 
numerous and can be found on hide, hoofs, tools, air, water and workers within the 
processing facility. Dockerty et al. (1970) found that scalding and singeing were helpful 
methods in decreasing microbes on the carcass of pigs. However, following the process 
of scalding and singeing, researchers found heading, eviscerating, and splitting of the 
carcass, increased microbial loads (Dockerty et al., 1970).  With the risk of animals, 
equipment, and workers increasing the microbial loads in meat, an impact at the pre-
harvest level will not solve all food safety issues. However, a reduction at one stage of 
production should logically produce an impact further down the production chain (Oliver 
et al., 2009). Therefore, supplementing antimicrobials to pigs prior to harvest could 
13 
 
potentially lead to cleaner pigs (both in their gastrointestinal tract and on their hide) 
entering the processing facility. 
Pre-Harvest Meat Quality 
 Food safety is always of utmost concern, and begins at the farm level. However, 
another continuous concern is meat quality, which can also be influneced at the farm 
level. Meat quality has become progressively more important to the pork industry as it 
faces the challenge of increased competition with other red meat species (Cannon et al., 
1996), and with improving its presence in a global market (Hasty et al., 2002). As 
Cannon et al. (1995) demonstrated in a pork quality audit, pork struggles with two main 
quality concerns: inadequate color and poor water-holding capacity. Lipid oxidation is 
another concern in the pork industry, and has also shown to affect the quality of color, 
water-holding capacity, flavor, texture, nutritive value, and safety (Buckley et al., 1995). 
Though there are many pre- and post- harvest methods that have been shown to improve 
pork quality, supplementing antioxidants in swine diets is one way that has been shown 
to increase multiple quality attributes in pork. 
Antioxidants 
  The supplementation of antioxidants in swine diets during the growing and 
finishing period has been shown to be beneficial in the improvement of pork quality 
(Cannon et al., 1996). Many researchers have determined that varying levels of vitamin E 
in the form of ?-tocopheryl used as a diet additive in pigs can help improve meat quality. 
Vitamin E is a potent antioxidant and has shown to decrease lipid oxidation, drip loss, 
and improves color of pork (Asghar et al., 1991; Monahan et al., 1990a,b, 1992). Vitamin 
14 
 
E improves pork quality through its antioxidant properties. (Buckley et. al., 1995). 
Antioxidants retard or inhibit lipid oxidation (Kim et al., 2003) by inhibiting radical 
forming enzymes (Nagao et al., 1999). 
 Cannon et al. (1996) determined that supplementation of vitamin E fed in the 
form of ?-tocopheryl at levels of 100mg/kg to growing pigs is successful in reducing 
lipid oxidation in pork. The reduction of lipid oxidation in pork has also been credited for 
prolonging shelf life in both fresh and frozen pork (Guo et al., 2006). Vitamin E increases 
color stability (Asghar et al., 1991), and increases a* values for refrigerated chops from 
pigs supplemented vitamin E, compared with chops from pigs receiving no vitamin E 
supplementation (Monahan et al., 1992). Lauridsen et al. (1999) attributed improvements 
of pork quality to improved water-holding capacity due to supplementing antioxidants in 
the form of vitamin E. By utilizing antioxidants in swine diets, pork producers can 
increase pork quality (Lauridsen et al., 1999), without altering taste or visual appearance 
(Cannon et al., 1995).  
Phenolics 
Plums 
 Over the last two decades, research has revealed that plums have a high phenolic 
content (Donovan et al., 1998; Gil et al., 2002; Kim et al., 2003; Nakatani et al., 2000; 
Wang et al., 1996) which could potentially be useful in both pre-harvest food safety and 
pre-harvest meat quality, due to the phenolic properties found in plums. Phenolics are 
composed of an aromatic benzene ring substituted with a hydroxl group (Kim et al., 
2003). Some forms of phenolics are free radical scavenger antioxidants ( Di Carlo et al., 
15 
 
1999) that protect cells from oxidative damage (Anderson et al., 1994). Plums have the 
strongest activity of all fruit and vegetables in the human diet (McBride, 1999). Other 
forms of phenolics are effective natural antimicrobials (Bowles and Juneja, 1998). 
Antimicrobial activity in phenolics is unclear, but theories of the reaction include; a 
reaction with the cell membrane, or inactivation of cellular enzymes, or possibly a 
combination of the two (Davidson & Branen, 1981). Other research has led to the theory 
that it may be related to the free hydroxyl group (Prindle & Wright, 1977). Phenolics can 
also serve as a natural colorant stability source (Francis, 1989). All forms of these 
phenolics are naturally found in plums, allowing plums to be a multi-functional phenolic 
source. It has been reported that the most effective antioxidant in plums is also one of the 
most effective antimicrobials. The antioxidant and antimicrobial, chlorgenic acid is 
typically found in high concentrations in plums (Davidson and Breanen, 1981). Another 
multi phenolic found in plums is anthocyanin, which has antioxidant (Igarashi et al., 
1989), antimicrobial (Beuchat and Golden, 1989), and color stability properties (Francis, 
1989).  
Plum Products 
 Plums are a versatile fruit, and can be consumed in a variety of way including in 
fresh, dried or juiced. Plum juice concentrate is obtained by extracting the juice from the 
fruit and elevating the concentration to 70? brix (70g sugar/100g juice) (Sunsweet 
Growers, 2008). Prunes are acquired by dehydrating fresh plums at 85-90?C for 18 hours 
(Piga et al., 2003). Plums have often been classified as a functional food, because of their 
unique chemical composition (Piga et al., 2003). The same benefits that are found in 
plums are also found in prunes and plum juice. Cevallos-Casals et al. (2006) determined 
16 
 
that levels of anthocyanin content, overall phenolic content and levels of antioxidant 
activity in prunes were higher over that of levels found in fresh plums. It is because 
plums and prunes possess such high levels of phenols that they are now being used to 
improve the meat industry. 
Functional Ingredient 
 The meat industry has typically used synthetic antioxidants such as BHA and 
BHT to inhibit oxidation and warmed over flavor (WOF) in meat products (Chastain et 
al., 1982; Chen et al., 1984; Sato & Hegarty, 1971), but with consumers becoming more 
concerned with potential toxicological effects (Decker & Mei, 1996; Rababah et al., 
2004), their preference is beginning to change to a more ?natural? label ( McCarthy et al., 
2001; Rhee et al., 2001). In recent years, plums and plum based products such as prune 
juice concentrate, plum puree, and plum juice concentrate have been researched as being 
used as a functional ingredient to help reduce foodborne pathogens, decrease lipid 
oxidation just as well as synthetic antioxidants, and increase the juiciness of meat, 
without altering the flavor of the product. The indigenous chemical compounds that make 
up plums serve specific functions when applied to foods, pectin aids in moisture 
retention, while malic acid enhances flavor, and sorbitol acts as a natural humecant 
(Nu?ez de Gonzalez et al., 2009). A study conduct by Fung (unpublished data), reported 
that a 3% prune extract solution when added to ground beef could suppressed 90% of 
foodborne pathogens, including Salmonella and E. coli. The antioxidant properties of 
prunes also work as a functional ingredient by reducing lipid oxidation and WOF in roast 
beef by adding either 2.5% fresh prune juice or 2.5% dried plum concentrate to a brine 
(Nunez de Gonzalez et al., 2008). Yildiz-Turp and Serdaroglu (2010) found that plum 
17 
 
puree could be incorporated to beef patties at levels of 5 or 10% without causing any 
detrimental effects to the product. When added at 5% patties resulted in highest cook 
yield and moisture retention, while 10% plum puree was most accepted during sensory 
analysis, and both levels were successful in inhibiting lipid oxidation. Lee and Ahn 
(2005) reported that when 3% of plum extract when added to low fat content meats, can 
improve mouth-feel due the sorbitol in the plums which helps to increase moisture in the 
product. Meat quality can also be improved by increasing juiciness, even when reheated 
when supplementing prune extract (Fung, unpublished data). Nutrient levels can also be 
increased by adding plum extracts to products due to the phenolic content, which is 
appealing to consumers (Leheska et al., 2006). Although different levels and forms of 
plums have shown to improve meat quality it has also shown that products darken color 
and become unacceptable to consumers (Nunez de Gonzalez et al., 2009). 
Conclusion 
Though, plum products are effective when supplemented as a functional 
ingredient in meat, not all consumers prefer an enhanced product. Previous research has 
focused on adding plum products to a meat product as a processing ingredient. Therefore, 
the objective of this study is to improve pre-harvest food safety and pre-harvest meat 
quality in pork by supplementing plum juice concentrate to growing / finishing pigs. 
Supplementing these natural antimicrobials and antioxidants in the form of plum juice 
concentrate, could potentially decrease microbial loads in feces of the pigs and 
furthermore, reduce the amount of microbes found on the hide of the animals at harvest. 
Another potential benefit of supplementing the antioxidants to pigs is the possibility of 
the plum juice concentrate in the pork meat to act as a functional ingredient to reduce 
18 
 
oxidation, warmed-over flavor, increase color stability, and increased overall shelf-life of 
the product. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
19 
 
 
 
III. EFFECTS OF FEEDING PLUM JUICE CONCENTRATE ON FECAL SHEDDING 
IN GROWING / FINISHING PIGS  
Abstract 
Yorkshire pigs (n=32) were fed at the Auburn University Swine Research and 
Education Center to determine the effects of adding plum juice concentrate (PJC) to 
growing / finishing pigs? diets on microbial shedding. Pigs were sorted by weight and sex 
(n=16 barrows, n=16 gilts) and assigned to a pen which housed two pigs per pen. Pens 
were randomly allotted to one of four treatment groups. Experimental diets contained 0% 
(Control), 0.5%, 1%, or 2.9% plum juice concentrate (PJC).  All basal diets consisted of 
corn and soybean meal formulated to meet or exceed National Research Council (NRC) 
recommendations. Pigs were allowed ad libitum access to feed and water, and treatment 
diets were formulated to be isocaloric. During the feed trial, fecal samples were collected 
from one pig per pen on days 0, 1, 7, 14, 28, 56, and the last day on feed (Group 1 =84 d; 
Group 2 =100 d). At an average pen weight of 114 kg pigs were humanely harvested and 
the ham of all pigs were swabbed following stunning, and exsanguination to determine if 
PJC could decrease microbes on the hide by decreasing microbial flora in the 
gastrointestinal tract. Fecal and ham swab samples were plated and enumerated for 
anaerobic (AA) and aerobic bacteria (APC). Samples were also enriched to determine 
prevalence of Salmonella spp. and generic E.coli (VRBA). Microbial analysis data were 
20 
 
analyzed using the GLM procedure. Results indicated Salmonella spp. was not present in 
any sample throughout the experiment and total counts for anaerobic bacteria, and E.coli 
were not different among any treatment. However, feeding PJC was effective in 
decreasing fecal bacterial populations for APC (P=0.03) when compared to the control. 
The fecal populations of bacteria among days did decrease for APC (P=<.0001), and 
VRBA (P=<.0001). Additionally, APC (P=0.52) and VRBA (P=0.34) counts were not 
different for day by treatment interaction.  However, there was a day by treatment 
interaction for AA (P=0.04) bacteria and showed a trend of decreasing bacterial 
populations for treatments 1.0% PJC as well as 2.9% PJC. In conclusion, the results of 
this study demonstrate that adding PJC to growing / finishing pigs? diets decreases 
aerobic bacteria and also decreases anaerobic, aerobic and VRBA counts from d 0 to d 
14.  
Introduction 
Microbial food safety is an increasing public health concern worldwide (Zhao et 
al., 2001). The United States food supply is among the safest in the world (Oliver et al., 
2009), however, every year people die, and countless others suffer due to breaches in 
food safety (Oliver et al., 2009). The most serious meat safety concerns, resulting in 
immediate consumer health problems and recalls from the market place, are from 
potentially contaminated products associated with bacterial pathogens (Sofos, 2008). 
Major causes of concern and product recalls stem from Salmonella and Escherichia coli 
(E.coli) 0157:H7 (Sofos, 2008). Salmonella infections are most commonly associated 
with the consumption of contaminated poultry, beef, and pork (Foley et al., 2008), while 
cattle are thought to be the primary reservoir of E.coli 0157:H7 (Rice et al., 2003), 
21 
 
research has also demonstrated fecal shedding by other domestic livestock such as pigs 
(Feder et al., 2003).  
Animals can become infected by several means; contact with other infected 
animals or pests, living in unclean facilities, consuming contaminated feed or water, or 
harboring pathogens on their hides from feces, soil or general environment (Oliver et al., 
2009). Of all these vectors, fecal shedding is correlated highest with carcass 
contamination (Elder et al., 2000). Therefore, the most significant intervention strategy in 
reducing pathogens in meat could be implementing pre-harvest food safety hurdles at the 
production level, to help prevent fecal shedding. 
Antibiotics are often included in pig diets to help control gastrointestinal 
pathogens by disrupting the intestinal microbial ecosystem, consequently improving food 
safety (Callaway et al., 2003). Antibiotics fed in sub-therapeutic levels however, have 
become highly controversial due to concern of antibiotic resistance in humans, and 
antibiotic-residue in animal products (Callaway et al., 2003, Schwarz et al., 2001). 
Therefore, ?natural? methods need to be researched. Fung, (unpublished data) reported 
that using a ?natural? antimicrobial in the form of a plum extract mixed in ground beef  
suppressed 90% of foodborne pathogens, including Salmonella and E. coli.  
Therefore, the objective of this study was to determine the effects of adding a 
?natural? antimicrobial to growing / finishing pigs? diets in the form of plum juice 
concentrate (PJC) on microbial loads and fecal shedding.  
 
 
22 
 
Materials and Methods 
Animals and Diets 
 Yorkshire pigs (n=32) were acquired at a BW of 22.68 kg + 4.54 kg and raised 
during the growing / finishing phases in an open barn with half concrete and half slatted 
floors at Auburn University Swine Research and Education Center (IACUC PRN: 2011-
1890). Pigs were sorted by weight and sex (n=16 barrows, n=16 gilts) and assigned to a 
pen which housed two pigs per pen. Pens were randomly allotted to one of four treatment 
groups. Experimental diets contained 0% (Control), 0.5%, 1%, or 2.9% plum juice 
concentrate (PJC).  All basal diets consisted of corn and soybean meal formulated to meet 
or exceed National Research Council (NRC) recommendations. Pigs were allowed ad 
libitum access to feed and water, and treatment diets were formulated to be isocaloric. 
During the feed trial fecal samples were collected directly from the anus of one pig per 
pen on days 0, 1, 7, 14, 28, 56, and the last day on feed (Group 1 =84 d; Group 2 =100 d). 
At an average pen weight of 114 kg pigs were transported (n=2 groups) to Auburn 
University Lambert - Powell Meats Laboratory, and held in lairage over-night. Pigs were 
humanely harvested under USDA ? FSIS inspection. The ham of all pigs were swabbed 
following stunning, and exsanguination to determine if PJC could decrease microbes on 
the hide by decreasing microbial flora in the gastrointestinal tract.  
 Microbial Analysis 
 Fecal samples were weighed, and buffered peptone water (BPW) (Neogen, 
Lansing, MI) was added in a 1:1 ratio. The sample was then stomached for 1 min at 240 
rpm (Seward, UK). Dilutions were made in 0.1% peptone water (PW) (Neogen, Lansing, 
23 
 
MI) and plated on Anaerobic Agar (AA) ( Becton Dickinson, Sparks, MD) to determine 
total anaerobic counts, Standard Methods Agar (APC) ( Neogen, Lansing, MI) to 
determine aerobic plate counts, Xylose-Lysine-Tergitol 4 (XLT4) ( Neogen Lansing, MI) 
to determine Salmonella spp. counts and  Violet Red Bile Agar (VRBA) ( Neogen, 
Lansing, MI) to determine coliform and generic Esherichia coli (E. coli) counts.  
Anaerobic agar was incubated in 7.0 L anaerobic chambers (Mitshubishi, Japan) with 
anaerogen sachets (Oxoid, Hampshire, UK) at 37?C for 48 h.  PCA, XLT4 and VRBA 
were incubated aerobically at 37?C for 24 h.  Results were reported as CFU/g. 
Prevalence of Salmonella spp. was determined by enriching the original fecal and 
BPW solution and incubating for 24 h at 37?C. From this, 0.1 mL was placed into 10 mL 
of Rappaport-Vassiliadis broth (RV) ( Neogen, Lansing, MI) and incubated at 37?C for 
24 h. Enriched samples were streak plated on XLT4 Agar and incubated at 37?C for 24 h. 
Results were reported as positive/negative. 
On the day of harvest, samples from the hams of individual pigs were obtained.  
Swabs containing neutralizing buffer (Swab Environtrans Hardy Diagnostics Santa 
Maria, CA) were used to sample an area 7.6 cm to the right of anus.   Samples were 
spread plated on AA, APC, XLT4 and VRBA and incubated as described above; results 
were reported as CFU/ cm2.  To determine prevalence of Salmonella, 1 mL of 
neutralizing buffer was placed into 9 mL BPW and incubated at 37?C for 24 h. From this, 
0.1 mL was added to 10 mL RV broth and incubated at 37?C for 24 h.  Enriched RV 
samples were streak plated on XLT4 and incubated for 24 h at 37?C.  Results were 
reported as positive/negative. 
24 
 
Statistical Analysis  
 Microbial data was analyzed using the GLM procedure (SAS, 2002). Pen was the 
experimental unit and independent fixed effects included diet and day. 
Results and Discussion 
Microbial Analysis  
 The effect of PJC on bacterial populations in feces of growing / finishing pigs is 
presented in Table 1. Salmonella spp. was not present in any sample throughout the 
experiment and no data is reported. Total anaerobic bacteria (P=0.63), and E.coli 
(P=0.12) were not different. Feeding PJC was effective in decreasing fecal bacterial 
populations for APC (P=0.03). Jin et al. (2008) conducted an experiment to compare 
supplementing antibiotics (positive control) to supplementing a natural antimicrobial to 
weanling pigs. The natural antimicrobial fed was potato protein at levels of 0.00% 0.25% 
0.50% and 0.75%. The results of that experiment compare to that of the present study. 
Data suggest that any level of antimicrobial fed to pigs does numerically decreased total 
bacteria. Fung, (unpublished) reported that by using plums as a functional ingredient 
could decrease pathogen growth in meat, however, that does not agree with the results of 
the present study.  
The effect of day on bacterial populations in feces of growing / finishing pigs is 
presented in Table 2.  The fecal populations of bacteria among days was different for AA 
(P=<.0001), APC (P=<.0001), and VRBA (P=<.0001). Anaerobic bacteria significantly 
decreased between d 1 and 7 (P=.0008), 14 and 28 (P<.0001), 56 and pre-harvest 
(P<.0001), and pre-harvest and post-harvest swab (P=<.0001). Aerobic bacteria 
25 
 
decreased between d 1 and 7 (P<.0001), and d 14 (P<.0001). Additionally, there was a 
difference between d 1 and post-harvest swab (P=<.0001). E.coli decreased between d 1 
and 7 (P=.0002), 1 and 14(P<.0001), 1 and 28 (P=.0002), and post-harvest swab 
(P=<.0001). This data compares to Jin et al. (2008) who reported a decrease for fecal 
populations of total bacteria, coliform bacteria, and Staphylococcus spp. on d 28. 
Staphylococcus also decreased at d 21 when fed the potato protein antimicrobial.  
Day by treatment interaction results are reported in Figures 1, 2, and 3. There was 
a diet by day interaction for anaerobic (P=0.04) bacteria counts, and showed a decreasing 
trend for control, 1.0%, and 2.9% treatments from d 0 to d 7, d 14 to 28, and d 56 to post-
harvest swab. Supplementing 0.5% PJC also showed a decrease in count between d 56 
and post-harvest swab. The reasons for these results are unclear. However, from d 0 to d 
14 there is a clear trend of decreasing counts for AA. This could indicate that as the pig 
increases in body weight levels of PJC need to be increased to meet microbial inhibiting 
levels.  
                                                     Implications 
The results of this study demonstrate that supplementing a PJC to growing / 
finishing pigs does decrease aerobic bacteria. This study also reveals that PJC does help 
to decrease anaerobic, aerobic and VRBA counts from d 0 to d 14. Further research is 
needed to identify if feeding PJC 14 d prior to harvest could result in lowest bacteria 
counts, or if continuing to increase levels of PJC as the pigs grow could help to reduce 
fecal bacteria populations.
26 
 
 
 
IV. GROWTH AND CARCASS CHARACTERISTICS OF PIGS FED PLUM JUICE 
CONCENTRATE AS A FEED ADDITIVE 
Abstract 
 Yorkshire pigs (n=32) were fed at the Auburn University Swine Research and 
Education Center to determine the influence of supplementation of plum juice 
concentrate (PJC) on growth, carcass, and quality characteristics of pork. Pigs were 
sorted by weight and sex (n=16 barrows, n=16 gilts) and assigned to a pen which housed 
two pigs per pen. Pens were randomly allotted to one of four treatment groups. 
Experimental diets contained 0% (Control), 0.5%, 1%, or 2.9% plum juice concentrate 
(PJC).  All basal diets consisted of corn and soybean meal formulated to meet or exceed 
National Research Council (NRC) recommendations. Pigs were allowed ad libitum 
access to feed and water, and treatment diets were formulated to be isocaloric. During the 
feed trial (Group 1=84 d; Group 2=100 d), feed intake and weight gain were measured 
every 14 d. Pigs were harvested (n=2 groups) at an average pen weight of 114 kg, and 
carcass and quality characteristics were recorded according to National Pork Producers 
Council Guidelines (2000). Growth and carcass data were analyzed using mixed model 
analysis (SAS, 2002). While, the level of PJC did not affect ADG, G: F or ADFI, there 
was a date of harvest effect on ADG (P=0.001) and G: F (P=0.009). Wetness was the 
only carcass characteristic to be affected by level of PJC supplement (P=0.02), however, 
muscle scores were higher (P=0.05) for pigs harvested on the first harvest day. Dressing 
27 
 
percentage was greater (P<.0001) for pigs harvested on the second harvest day. Fat 
thickness measured along the midline of the 10th rib was thicker (P=0.02) for barrows 
and barrows had a greater (P=.0005) loin pH. Feeding of PJC as a feed additive had no 
effect on quality characteristics; however, pigs from the second harvest date had lower 
Warner-Bratzler shear force values (P=0.02). There were no differences in initial or 
sustained tenderness or juiciness, pork flavor intensity or off flavor (P>0.05). Finally, 
gilts had more fat free lean (P=0.05), percentage fat free lean (P=0.006), and drip loss 
(P=0.03), but barrows had a higher percentage (P=0.04) cook loss. Independent of 
harvest group or sex, these results indicate that the supplementation of PJC has no effect 
on growth, carcass, or quality characteristics of pork.  
Introduction 
Consumers scrutinize food more today than they did in the past (Troy and Kerry, 
2010) and their preference is beginning to change to a more ?natural? label (McCarthy et 
al., 2001; Rhee et al., 2001). Though consumers pay more attention to credence qualities 
like safety, healthiness, convenience, locality, and ethical factors (Bernu?s 2003; 
Issanchou, 1996), consumers still take into consideration meat quality attributes such as; 
meat color, visible drip, and visible fat (Troy and Kerry, 2010). 
The meat industry has typically used synthetic antioxidants such as butylated 
hydroxyanisole (BHA) and Butylated hydroxytoluene (BHT) to inhibit oxidation and 
improve meat quality (Chastain et al., 1992; Chen et al., 1984; Sato & Hegarty, 1971), 
but with consumers becoming more concerned with potential toxicological effects 
(Decker & Mei, 1996; Rababah et al., 2004) different methods have been studied. 
28 
 
 The supplementation of antioxidants in swine diets during the growing and 
finishing period has shown to be beneficial in the improvement of pork quality (Cannon 
et al., 1996). Supplementing the antioxidant, Vitamin E in the form of ? ? tocopherol has 
shown to decrease lipid oxidation, drip loss, and improve color of pork when 
supplemented to growing / finishing pigs (Asghar et al., 1991; Monahan et al., 1990a, b, 
1992).  
Another method of improving pork quality through the use of antioxidants is post-
harvest enhancement of the product. In recent years, research has identified plums as a 
functional ingredient to help reduce foodborne pathogens, decrease lipid oxidation, and 
increase the juiciness of meat without altering the flavor of the product. The indigenous 
chemical compounds that make up plums serve specific functions when applied to foods.  
Pectin aids in moisture retention, while malic acid enhances flavor, and sorbitol acts as a 
natural humectant (Nu?ez de Gonzalez et al., 2009). These attributes have been credited 
for decreasing lipid oxidation, and warmed over flavor (WOF), as well as increasing 
mouth-feel, juiciness, and nutrients (Nunez de Gonzalez et al., 2008, Yildiz-Turp and 
Serdaroglu 2010, Leheska et al., 2006, Lee and Ahn 2005). 
The objective of this study was to determine the effect of supplementing growing 
/ finishing pigs? diets with an antioxidant in the form of plum juice concentrate on growth 
performance, carcass characteristics, and overall meat quality. 
Materials and Methods 
Animals and Diets 
 Yorkshire pigs (n=32) were acquired at a BW of 22.68 kg + 4.54 kg and were 
raised during the growing finishing phases in an open barn with half concrete and half 
29 
 
slatted floors at Auburn University Swine Research and Education Center (IACUC PRN: 
2011-1890). Pigs were sorted by weight and sex (n=16 barrows, n=16 gilts) and assigned 
to a pen which housed two pigs per pen. Pens were randomly allotted to one of four 
treatment groups. Experimental diets contained 0% (Control), 0.5%, 1%, or 2.9% plum 
juice concentrate (PJC).  All basal diets consisted of corn and soybean meal formulated to 
meet or exceed National Research Council (NRC) recommendations. Pigs were allowed 
ad libitum access to feed and water, and treatment diets were formulated to be isocaloric. 
During the feed trial (Group 1 =84 d; Group 2 =100 d) feed intake and weight gain were 
measured every 14 d. At an average pen weight of 114 kg pigs were transported to 
Auburn University Lambert - Powell Meats Laboratory.  
Harvesting and Carcass Data 
Pigs were humanely harvested at Auburn University Lambert ? Powell Meats 
Laboratory under USDA ? FSIS inspection. Carcasses were chilled for 24 h at 2 ? 1?C. 
The pH was monitored in both the right loin and ham at 30 min, 45 min, 3 h, 6 h, and 24 
h after the time the animal was stunned. The pH was measured by using a portable pH 
spear probe meter (pH Spear. Eutech Instruments Oakton). Both live weight and hot 
carcass weight were recorded to determine dressing percentage. Following the 24 h chill 
period, carcasses were ribbed between the 10th and 11th rib. Backfat was measured at the 
10th and last rib, and loin eye area (LEA) was also measured. Backfat and LEA were 
adjusted based on the recommended equation of NPPC (2000).  
 Adjusted Backfat to 250 lb. =  
Actual Backfat + [(250-actual wt.) x actual backfat/ (actual wt.-b)] 
30 
 
 Adjusted LEA to 250 lb. =  
  Actual LEA + [(250-actual wt.) x actual LEA/ (actual wt. + 155)] 
Evaluation of subjective scores for marbling, wetness, firmness, and muscle score, 
were determined by a trained observer using published visual standards (NPPC 2000). 
Additionally,  the longissimus muscle at the  10th rib was evaluated for objective color 
measurements with a Hunter Miniscan XE Plus (Hunter Lab, Reston, VA) to determine 
Hunter L*, a*, and b* values. The Miniscan was calibrated according to the 
manufacturer?s recommendations and utilized a D65 light source, a 10? viewing angle, 
and a 35mm viewing area. Following carcass evaluation, a section of the longissimus 
muscle was removed from the 11th rib to the last lumbar vertebrae from each carcass to 
use for meat quality analysis. Starting at the 11th rib end, one 5.1cm thick chop was cut 
for drip loss, moisture uptake (MU), and marinade cook loss (MCL). One 2.54cm thick 
chop was removed for fatty acid analysis, two for Warner-Bratzler Shear Force (WBS) 
determination, one for Thiobarbituric Acid Reactive Substances (TBARS), and two for 
sensory evaluation. Chop samples for drip loss, MU, and MCL were analyzed fresh, 
while chops for FA, WBS, TBARS, and sensory were vacuum packaged and frozen for 
later analysis.  
Meat Quality Analysis 
Drip Loss, Marinade Uptake, and Marinade Cook Loss 
 One 5.1cm fresh chop was fabricated from the longissimus muscle and cut to two 
4cm thick cubes weighing between 40 to 50 g. Samples were then trimmed free of fat and 
connective tissue. Cubes were weighed, then suspended by a fish hook (Model 
31 
 
number:121 ? 2/0, Eagle Claw?) in a plastic sample cup (500 mL Polypropylene Straight 
?Sided Jar, Nalgene?, VWR International, LLC., West Chester, PA, USA) for 48 h at a 
temperature of 4?C. Following the 48 h time period samples were removed from hooks 
and blotted to remove excess surface fluid. Samples were then weighed to the nearest 
0.1g. Percent drip was calculated by NPPC (2000) recommended equation, and averaged 
across the two samples for each pig.  
 Percent Drip Loss = 
  (Loss in Weight / Initial Weight) x 100 
 Using excess trim from fabricating one 5.1cm into two 4cm cubes for drip loss, 
the meat was ground using a coffee bean grinder, (Mr. Coffee Inc., Cleveland, Ohio) and 
separated into triplicate samples weighing 6.00 + 0.01, and placed in 50 ml centrifuge 
tube that were weighed  to the nearest 0.01 g without the cap on. 10 ml of reagent buffer 
(3.5% NaCl = 35 g in 1 liter of water) was added to each sample and vortexed for 15 s 
before being placed in a water bath to incubate for 30 min at 25?C. Following incubation, 
samples were centrifuged using a Beckman Coulter Allegra X-15 R (Beckman Coulter, 
Inc., Brea, CA, USA) swinging bucket rotor for 20 m at 3000 rpm and 13?C. Samples 
were then left upside down to drain for 5 min, and weights were recorded with the cap off 
to the nearest 0.01 g. Moisture uptake was then calculated by using the NPPC (2000) 
equation and an average was determine across each set of triplicates.  
 Moisture Uptake = 
[(weight tube and meat, after incubation at 25?C) ? (initial weight of tube and 
meat)/6.00g x 100] 
32 
 
 Additionally, marinade cook loss was analyzed by using the drained triplicate 
samples from MU. Samples were placed into an 80?C water bath and left for 20 m. Once 
samples were removed from the water bath they were left to cool to an average 
temperature of 21?C, and weight were recorded of tubes with cap off. The NPPC (2000) 
equation was used to calculate MCL before calculating averages for each pig.  
 Marinade Cook Loss =  
[(weight of tube and meat, after cooking) ? (initial weight of tube and meat)/6.00g] x 100 
Fatty Acid Analysis 
 All fatty acid standards were purchased through Nu-Chek Prep Inc., Elysian, 
Minnesota, except Hexanes (J.T. Baker, Phillipsburg, New Jersey), MeOH (Fisher 
Scientific, Fair Lawn, New Jersey), KOH (Sigma-Aldrich, St. Louis, Missouri), and  
Supelco standard FAME mixture (47885-U) (Supelco, Bellefonte, Pennsylvania).  
 Frozen samples were thawed to room temperature. Samples were uniformly 
distributed by grinding for 10 to 15 s in a room-temperature coffee bean grinder (Mr. 
Coffee Inc., Cleveland, Ohio). 1.0 g of meat was placed into a 16 ? 125 mm screw-cap 
Pyrex culture tube (Corning Laboratory Science Company, New York)  to which 1.0 mL 
of the C13:0 internal standard (0.5 mg of C13:0/mL of MeOH), 0.7 mL of 10 N KOH in 
water, and 5.3 mL of MeOH were added. The tube was incubated in a 55?C water bath 
for 1.5 h with vigorous hand-shaking every 20 min to properly permeate, dissolve, and 
hydrolyze the sample. After cooling below room temperature in a cold tap water bath, 
0.58 mL of 24 N H2SO4 in water was added. The tube was mixed by inversion and with 
precipitated K2SO4 present was incubated again in a 55?C water bath for 1.5 h with hand-
33 
 
shaking every 20 min.  
After FAME synthesis, the tube was cooled in a cold tap water bath. Three 
milliliters of hexane was added, and the tube was mixed for 5 min on a vortex. The tube 
was then centrifuged for 5 min in a Beckman-Coulter Allegra X-15R centrifuge, and the 
hexane layer, containing the FAME, was removed and placed into a 2ml GC vial. The 
vial was capped and placed at -20?C until GC analysis.  
 The fatty acid composition of the FAME was determined by capillary GC on a 
SP-2560, 100m ? 0.25 mm ? 0.20 ?m capillary column (Supelco) installed on a 
Shimadzu 2014 gas chromatograph equipped with a Shimadzu AOC-20i auto injector, a 
flame ionization detector, and split injection. The initial oven temperature was 140?C, 
held for 5 minutes, subsequently increased to 240?C at a rate of 4?C min-1, and then held 
for 20 minutes. Helium was used as the carrier gas at a flow rate of 0.5 mL_min-1, and 
the column head pressure was 280 kPa. Both the injector and the detector were set at 
260?C. The split ratio was 30:1. Fatty acids were identified by comparing their retention 
times with FAME standards purchased from Supelco.  
Warner-Bratzler Shear Force and Cook Loss 
 Warner Bratzler shear force (WBS) evaluation was performed using pork loin 
chops cut to 2.54cm thickness were thawed in a vacuum package bag at approximately 
4?C for 24 h. Chops were weighed and placed on a Calphalon Removable Plate Grill 
(Caphalon, Perrysburg, OH) clamshell style contact grill pre-heated to 177?C. 
Temperature was monitored with copper constantan thermocouple wire inserted into the 
geometric center of the chop and attached to a hand-held Omega data logger HH309A 
34 
 
(Omega, Stamford, CT) temperature recorder. Chops were cooked for 7 min which 
resulted in a final temperature of 71?C. Cooked chops were removed and reweighed 
before being placed on non-absorbent wax-coated paper to cool to room temperature then 
chops were wrapped in aluminum foil and placed in refrigerator at 4?C for approximately 
24 h. Six 1.27cm-diameter cores were removed from each chop with a brass cork borer 
(Model 1601A Series Brass Cork Borer, Boekel Scientific, Feasterville, PA) parallel to 
the longitudinal orientation of the muscle fibers. Each core was sheared once at its center 
using a TA-XT2i Texture Analyser (Texture Technologies Corp., Scarsdale, NY). The 
peak force measurements were averaged from the six cores of each sample and were used 
for analysis. The probe was programmed to be lowered 30 mm after detection of 
resistance.  The penetration speed was 3.3 mm/s with a post-test speed of 10 mm/s and a 
pre-test speed of 2.0 mm/s. Cook loss was measured as the percent of pre-cooked weight 
lost during cooking. 
 Cook Loss =  
  (Initial weight ? Cooked weight) x 100 
Thiobarbituric Acid Reactive Substances  
 TBARS were determined using a modified method of Wang et al. (2003). Briefly, 
five grams of meat free of fat and connective tissue were homogenized in 15 mL of 7.5% 
trichloroacetic acid, 0.1% propyl gallate, and 0.1% EDTA using a bullet style blender 
(Bella Cucini Rocket Blender, Bella Cucina Artful Food, Inc., Montreal Canada) for 
approximately 30 s. Samples were then centrifuged at 1,500 x g using a Beckman Coulter 
Allegra X-15 R (Beckman Coulter, Inc., Brea, CA, USA) swinging bucket rotor. After 
35 
 
centrifugation, samples were filtered through no. 4 Whatman paper (Whatman, plc, Kent, 
UK). Samples were then loaded into a 96-well microplate (Greneir Bio-one, 
Frickenhausen, Germany) 32 samples in triplicate wells and incubated at 40?C for 130 
min in a VWR Incubating Microplate Shaker (VWR International, LLC., West Chester, 
PA, USA). Microplates were then read using a Multiskan EX (Thermo Fisher Scientific, 
Waltham, MA, USA ) absorbance reader at 540 nm.  
 Standards were made using a stock solution of tetraethoxypropane (TEP) at 1 
mM/L. The stock solution was diluted to 0, 2, 4, 6, 8, 10, 20, and 30 ?M/mL. A standard 
curve was then generated for each plate and used for the samples on each respective 
plate, and results are expressed as mg malondialdehyde / kg meat.  
Sensory Evaluation 
 A trained panel of nine members conducted a sensory evaluation of boneless top 
loin chops according to guidelines by AMSA (1995). Chops were cooked as previously 
described for WBS evaluation. Chops were allowed to rest before being cut into 1cm x 
1cm x cooked chop thickness pieces, and placed in a plastic cup with lids. Samples were 
held in a warming oven for a minimal amount of time prior to sensory evaluation. Two 
pieces of each sample were given to panelist to evaluate for initial and sustained 
juiciness, initial and sustained tenderness, pork flavor, off flavor intensity, and off flavor 
descriptor on a 8 point scale, where 1 = extremely dry, extremely tough, extremely bland, 
and no off flavor, and 8 = extremely juicy, extremely tender, extremely intense pork, and 
extremely off flavor respectively. Panelists were instructed to cleanse their palate with a 
salt-free saltine cracker and sip apple juice before each sample. Panel members evaluated 
36 
 
samples over a four day period (n= 32 total samples, 8 samples per d) in secluded 
partitioned booths with red incandescent light.  The form given to sensory panelist to 
evaluate samples can be found in Appendix F.  
Statistical Analysis  
  Data were analyzed using mixed model analysis (SAS, 2002). Pen was the 
experimental unit and independent fixed effects included: diet, sex, rep, and harvest 
group.  
Results and Discussion 
Animal Diets 
 Treatment effect of supplementing PJC to growing / finishing pigs is presented in 
Table 4. There were no differences in ADG, G: F, ADFI, or finishing live weight among 
treatments. However, in comparison with harvest group 2, group 1 had improved ADG 
(P=0.01), G: F (P=0.07), and finishing live weight (P=0.005) (Table 5). Blair and English 
(1965) demonstrated that barrows are more efficient and grow faster than gilts. Therefore, 
improved growth performance among harvest group 1 may be associated with the pigs of 
that group being majority barrows. Although supplementing varying levels of PJC did not 
differ from the control group, these results agree with similar studies which supplemented 
an antioxidant (Vitamin E), in which no difference in growth performance or feed 
efficiency was observed (Amer and Elliot 1973, Roth and Kirschgessner, 1975, Monahan 
et al., 1990, and Cannon et al., 1996).
 
37 
 
Carcass Data 
 The effect of treatment, sex and harvest group of ham and loin pH is presented in 
figures 4, 5, 6, and 7. Pigs across all treatments showed a gradual decline in ham pH, 
resulting in quadratic (P=0.005) effect. Loin pH concluded that gilts had a lower pH 
(P=0.0005) than barrows, and also tended to have a lower ultimate loin pH (P=0.06). The 
results of the present study disagree with results of Eikelenboom and Hoving-Bolink 
(1993) who suggest gilts maintain a higher pH than barrows. This discrepancy may be 
caused by a difference of temperature on day of harvest, in which predominantly gilts 
were harvested on the cooler of the two days. Lefaucheur et al. (1991) demonstrated that 
temperature does have an effect on pH, reporting that pigs reared in cooler temperatures 
resulted in a faster postmortem pH decline and lower ultimate pH in the longissimus dorsi 
muscle.  
The effect of treatment, sex, and harvest group on carcass characteristics of pig 
supplemented PJC are presented in tables 6, 7, 8 and 9. Pigs in harvest group 2 had a 
higher dressing percentage (P= <.0001) than that of harvest group 1. Pigs in group 2 were 
majority gilts, in which our results would agree with previous research that states females 
tend to have a higher dressing percentage (Langlois and Minivelle, 1989). There were no 
differences in hot carcass weight (HCW) among sex or harvest group which could be 
attributed to group 1 having higher live weights, while group 2 had higher dressing 
percentages and therefore may have balanced overall HCW between harvest groups.  
There was no difference in last rib fat, however gilts were leaner when measured 
at the 10th rib (P=0.02). Gilts also had lower adjusted back fat (P=0.02), higher fat free 
lean (P=0.05), higher percent fat free lean (P=0.006) larger loin eye area (LEA) and 
38 
 
larger adjusted LEA (P=0.02) than barrows.  These results agree with Friend and 
MacIntyre (1970) who reported gilts being leaner and having larger LEA. Barrows had 
increased marbling (P=0.04) and pigs that were harvested first (group 1) tended to have a 
higher muscle score (P=0.05). This is likely because the majority of group 1 were 
barrows, which are more efficient and grow faster (Blair and English, 1965).  
There were no differences for Hunter L* and a*, yet gilts tended to have lower b* 
value (P=0.07). These results agree with others (Cannon et al., 1996; Houben et al., 1998; 
Zanardi et al., 1999) who observed no effects on Hunter L* a* b* when supplementing an 
antioxidant of vitamin E on color of fresh pork. Firmness of LEA showed no difference, 
however, wetness did vary among treatments (P=0.02), with treatment of 0.5% PJC 
producing the most ideal wetness of a 2. The present study carcass data results agree with 
Cannon et al. (1996) who supplemented varying levels of the antioxidant, Vitamin E and 
reported no differences among treatments. However, the treatment effect of wetness was 
not expected, the more antioxidants supplement tended to be the most exudative. This 
contradicts previous research which suggests antioxidants can help to increase water-
holding capacity (Lauridsen et al., 1999).  
 
Meat Quality 
Drip Loss, Marinade Uptake, and Marinade Cook Loss 
 The effect of treatment, sex, and harvest group on drip loss, marinade uptake, and 
marinade cook loss are presented in Tables 10 and 11. There were no differences among 
treatments for MU, MCL, or drip loss. This is in agreement with Cannon et al. (1996), 
who reported no effect of adding antioxidants (vitamin E) to growing / finishing pigs? 
diets  on drip loss in fresh loin chops. In contrast, Lauridsen et al. (1999) and Cheah et al. 
39 
 
(1995) observed a reduction in drip loss in longissimus samples when measured 
following slaughter. Yildiz ? Turp and Serdaroglu, (2010) reported beef patties 
formulated with plum puree had lower cooking yields and Nu?ez de Gonzalez et al. 
(2008) stated that increasing plum contents to roast beef also increased cooking loss. 
Yildiz ? Turp and Serdaroglu, (2010) attribute low cook yields to plums blocking the 
effect on water binding ability of meat proteins. In contrast University of Arkansas 
(Unplubished data), reports water holding capacity analysis showed that plum fiber 
marinade retained moisture as well as the phosphate control, however plum fiber 
marinade chicken did have a higher cook loss.  
Although there was no treatment effect on drip loss, there was a sex effect 
(P=0.03) in which gilts had a higher percentage drip loss. This suggest that females had 
more free water present, which could be due to the high pH that the males maintain 
causing the water to become more immobilized. 
 
Fatty Acid Analysis  
 The effect of treatment and sex for fatty acid levels in pigs supplemented PJC are 
presented in Tables 12 and 13. Barrows had an increase percentage of C16:0 (P=0.01), 
C17:1 (P=0.01) and total saturated fatty acids (SFA) (P=0.01). Females had an increase 
percentage of C22:6n3 (P=0.01), ratio (omega-3 to omega-6 ratio) (P=0.04), and omega-3 
(P=0.02) fatty acids . The current data agrees with Zhang et al, (2007) who reported 
barrows had higher concentrations of SFA and mono unsaturated fatty acids. N?rnberg et 
al, (2005), also reported that barrows had higher levels of SFA than gilts. Although pigs 
fed 0.5% PJC showed to have highest levels of C 18:2 N6T (P=0.03) there is no 
40 
 
circumstantial evidence to suggest treatment should play a role in FA levels, because 
there are no increased levels of FA in PJC. 
Warner-Bratzler Shear Force and Cook Loss 
 The effect for treatment, sex, and harvest group on WBS and cook loss of pigs 
supplemented PJC is presented in Tables 10 and 11. There were no differences among 
treatments for WBS or percent cook loss. However, results showed that harvest group 1 
was less tender than harvest group 2 (P=0.02) when analyzed by WBS method (1.43 kg 
vs. 1.15 kg, respectively). Results also showed that cook loss was greater for males 
(P=0.04) majority of which were harvested in group 1. These results are likely due to pigs 
being harvested under extreme heat conditions of that particular day, which could have 
implicated in the resulting PSE carcasses. PSE meat develops a looser muscle structure 
and is associated with a lower water-holding capacity, resulting in a tougher product 
(Romans et al. 2001). These results agree with van der Wal et al. (1988), who reported a  
difference in toughness and cook loss in PSE pork loins than in DFD pork loins.  
Thiobarbituric Acid Reactive Substances 
 There were no differences among treatments or sex for TBARS. The results 
support a previous study by Cannon et al. (1996), who determined that thiobarbituric acid 
values were unaffected after vacuum packaging and allowing one day of display. In 
contrast, it has been reported TBARS values decrease when plum puree is added to beef 
patties at levels of 5 and 10 percent (Yildiz ? Turp and Serdaroglu, 2010). Therefore, the 
results of the presents may not have been supplemented at high enough concentration to 
warrant uptake into the muscle tissue.  
41 
 
Sensory Evaluation 
 The effect of treatment, sex, and harvest group on sensory attributes of pig 
supplemented PJC is presented in Tables 14 and 15. PJC did not influence sensory 
characteristics of tenderness, juiciness, pork flavor intensity, or off flavor intensity. 
Although, PJC did not increase sensory attributes, it also did not decrease sensory 
attributes, therefore maintaining consumers? expectations. These results agree with 
Nu?ez de Gonzalez et al. (2008) who reported small changes among treatments of plum 
added to boneless beef roast.  Therefore, the results of the present study  may not have 
been supplemented at high enough concentration to warrant uptake into the muscle tissue 
to have results similar to Yildiz ? Turp and Serdaoglu (2010), who reported enhancing 
beef patties at levels of 5% and 10% with plum puree increased juiciness, texture, and 
sweetness.  
Implications 
 Growth performance, carcass characteristics and meat quality were unaffected by 
supplementation of plum juice concentrate in growing / finishing pig diets. Therefore, 
adopting this method appears to be ineffective. However, there is a potential that the 
levels fed in this study were not high enough to warrant any meat quality differences. 
Additionally, plums are known antioxidants and could potentially help to improve 
growth, carcass and meat quality if fed in different forms, such as the fruit itself, or by 
adding PJC in growing / finishing pigs? diets at the increased and successful percentages 
that have been achieved by previous post-harvest enhancement research. 
42 
 
 
 
  
 
Table 1. LS Means ? SEM for Treatment Effects of Feeding PJC to Growing / Finishing Pigs on Anaerobic, Aerobic, and VRBA Plate 
Counts 
 Treatment  
Plate Control 0.5% 1.0% 2.9% P > F 
Anaerobic 5.96 ? 0.14 5.88 ? 0.14 5.72 ? 0.14 5.93 ? 0.14 0.63 
Aerobic 6.14 ? 0.014a 5.60 ? 0.14b 5.80 ? 0.14abc 5.68 ? 0.14bc 0.03 
VRBA 5.65 ? 0.19 5.06 ? 0.19 5.55 ? 0.19 5.29 ? 0.19 0.12 
abc Values within same row with same superscript are not different (P>0.05) 
  
43 
 
 
 
 
 
Table 2. LS Means ? SEM for Day Effects of Feeding PJC to Growing / Finishing Pigs on Anaerobic, Aerobic, and VRBA Plate 
Counts 
 Day  
Plate 0 1 7 14 28 56 Pre-Harvest Post-Harvest Swab P > F 
Anaerobic 7.00 ? 0.20a 6.50 ? 0.20ab 5.51 ? 0.20cde 5.99 ? 0.21bc 5.06 ? 0.20df 7.59 ? 0.20 5.27 ? 0.20ef 4.05 ? 0.20 <.0001 
Aerobic 7.11 ? 0.20 6.00 ? 0.20a 5.26 ? 0.20bc 4.89 ? 0.20bd 5.46 ? 0.20c 6.14 ? 0.20ae 6.53 ? 0.20e 5.07 ? 0.20cd <.0001 
VRBA 6.39 ? 0.27a 6.40 ? 0.27a 5.17 ? 0.27b 4.48 ? 0.27b 5.18 ? 0.27b 6.02 ? 0.27a 6.25 ? 0.27a 3.19 ? 0.27 <.0001 
abcdef Values within same row with same superscript are not different (P>0.05) 
 
  
44 
 
  
 
 
 
 
 
 
Table 3. Composition (as-fed basis) of Experimental Basal Diets for Growing / Finishing Phases 
 
  
Item Growing Phase Finishing Phase 
% Protein 13.7 12.7 
Metabolized Energy, Kcal/kg 3531 3509 
% Fat 8.5 8 
% Calcium  0.51 0.46 
% Phosphorus 0.39 0.36 
45 
 
 
 
  
 Treatment  
     Control  0.5% PJC  1.0% PJC  2.9% PJC  P>F 
ADFI, kg/d 2.34 ? 0.20 2.37 ? 0.20 2.26 ? 0.18 2.21 ? 0.18 
 
0.57 
 
G:F, kg/kg 0.40 ? 0.01 0.41 ? 0.01 0.42 ? 0.01 0.41 ? 0.01 
 
0.41 
 
ADG, kg/d 0.93 ? 0.06 0.97 ? 0.06 0.95 ? 0.05 0.89 ? 0.06 
 
0.25 
 
Finishing 
Live Wt., kg 
 
104.55 ? 5.31 109.49 ? 5.31 106.27 ? 4.71 102.32 ? 4.92 0.22 
Adj. Days 
250 lbs.  
 
169.55 ? 3.10 165.36 ? 3.10 166.29 ? 2.85 173.23 ? 2.96 0.27  
Table 4. LS Means ? SEM for Treatment Effects of Feeding PJC to Growing / Finishing Pigs on ADFI, G:F, ADG, Finishing Live Wt, 
and Adj. Days 250 lbs. 
46 
 
 
 
Table 5. LS Means ?  SEM for Sex and Harvest Group Effects of Feeding PJC to Growing / Finishing Pigs on ADFI, G:F, ADG, 
Finishing Live Wt., and Adj. Days 250 lbs. 
 
 
 
 
 Sex  Harvest Group  
 
 
Barrow 
 
Gilt P>F 1 2 P>F 
ADFI, kg/kg 2.40 ? 0.18 2.20 ? 0.18 0.19 2.37 ? 0.18 2.22 ? 0.18 0.30 
G:F, kg/kg 0.39 ? 0.01 0.42 ? 0.19 0.15 0.43 ? 0.01 0.39 ? 0.01 0.07 
ADG, kg/d 0.94 ? 0.05 0.93 ? 0.05 0.70 1.01 ? 0.05 0.87 ? 0.05 0.01 
Finishing 
Live Wt., kg 106.41 ? 5.46 104.91 ? 5.46 0.74 112.68 ? 5.46 98.64 ? 5.46 0.005 
Adj. Days 
250 lbs.  166.03 ? 2.84 171.19 ? 2.84 0.31 153.87 ? 2.84 183.35 ? 2.84 <.0001 
47 
 
 
 
Table 6. LS Means ?  SEM for Treatment Effects of Feeding PJC to Growing / Finishing Pigs on HCW, Dressing Percentage, LEA, 
Adj. LEA, Last Rib Fat, Adj. Back Fat, and Muscle Score 
 Treatment  
     Control 0.5% PJC 1.0% PJC 2.9% PJC P>F 
HCW, kg 77.88 ? 4.53 82.50 ? 4.53 82.16 ? 4.02 78.43 ? 4.19 0.27 
Dressing 
Percentage 74.88 ?0.86 75.82 ? 0.86 77.49 ? 0.76 76.91 ? 0.79 0.12 
LEA, cm2 42.90 ? 0.21 48.00 ? 0.21 46.83 ? 0.18 45.55 ? 0.19 0.09 
Adj. LEA, cm2 45.29 ? 0.22 49.48 ? 0.22 48.90 ? 0.20 48.65 ? 0.20 0.21 
10th Rib Fat, cm 2.2 ? 0.07 2.1 ? 0.07 2.1 ? 0.06 2.0 ? 0.06 0.81 
Last Rib Fat, cm 2.4 ? 0.07 2.7 ? 0.07 2.7 ? 0.06 2.7 ? 0.06 0.68 
Adj. Back Fat, 
cm 2.3 ? 0.07 2.1 ? 0.07 2.3 ? 0.06 2.2 ? 0.06 0.76 
Muscle Score 1.97 ? 0.07 2.19 ? 0.07 2.13 ? 0.06 2.03 ? 0.06 0.17 
 
 
 
48 
 
 
abc Values within same row with same superscript are not different (P>0.05) 
 
 
 
 Treatment  
 Control 0.5% PJC 1.0% PJC 2.9% PJC P>F 
Marbling 1.57 ? 0.19 1.38 ? 0.19 1.50 ? 0.17 1.18 ? 0.18 0.47 
Wetness 1.81ab ? 0.16 2.00a ? 0.16 1.50bc ? 0.14 1.31c ? 0.15 0.02 
Firmness 1.46 ? 0.20 1.83 ? 0.20 1.25 ? 0.18 1.40 ? 0.19 0.22 
L* 59.76 ? 1.33 58.06 ? 1.33 59.70 ? 1.18 61.83 ? 1.23 0.25 
a* 10.61 ? 0.59 10.64 ? 0.59 10.61 ? 0.53 11.55 ? 0.55 0.56 
b* 17.22 ? 0.88 16.37 ? 0.88 17.53 ? 0.78 18.20 ? 0.81 0.51 
% FFL 52.29 ? 1.01 53.95 ? 1.01 53.10 ? 0.90 53.99 ? 0.94 0.63 
FFL, kg 40.67 ? 2.30 44.37 ? 2.30 43.62 ? 2.04 42.13 ? 2.13 0.12 
Table 7. LS Means ?  SEM for Treatment Effects of Feeding PJC to Growing / Finishing Pigs on Marbling, Wetness, Firmness, L*, a*, b*, 
PFFL, and FFL 
49 
 
 
Table 8. LS Means ?  SEM for Sex and Harvest Group Effects of Feeding PJC to Growing / Finishing Pigs on HCW, Dressing 
Percentage, LEA, Adj. LEA, Last Rib Fat, Adj. Back Fat, and Muscle Score 
 Sex Harvest Group  
           Barrows Gilts P>F 1 2 P>F 
HCW, kg 80.76 ? 4.65 79.72 ? 4.65 0.79 80.25 ? 4.65 80.23 ? 4.65 0.99 
Dressing 
Percentage 76.08 ? 0.88 76.47 ? 0.88 0.81 71.36 ? 0.88 81.19 ? 0.88 <.0001 
LEA, cm2 42.90 ? 0.21 48.77 ? 0.21 0.03 45.42 ? 0.21 46.26 ? 0.21 0.73 
Adj. LEA, cm2  44.77 ? 0.23 51.42 ? 0.23 0.02 45.74 ? 0.23 50.39 ? 0.23 0.10 
10th Rib Fat, cm 2.5 ? 0.07 1.7 ? 0.07 0.02 2.1 ? 0.07 2.1 ? 0.07 0.94 
Last Rib Fat, cm 2.7 ? 0.07 2.6 ? 0.07 0.56 2.9 ? 0.07 2.4 ? 0.07 0.12 
Adj. Backfat, 
cm 2.6 ? 0.07 1.8 ? 0.07 0.02 2.1 ? 0.07 2.3 ? 0.07 0.42 
Muscle Score 2.02 ? 0.07 2.13 ? 0.07 0.38 2.21 ? 0.07 1.95 ? 0.07 0.05 
 
 
 
 
 
50 
 
 
 
Table 9. LS Means ?  SEM for Sex and Harvest Group Effects of Feeding PJC to Growing / Finishing Pigs on Marbling, Wetness, 
Firmness, L*, a*, b*, PFFL, and FFL 
 
 Sex Harvest Group 
 Barrow Gilt P>F 1  2 P>F 
Marbling 1.79 ? 0.20 1.02 ? 0.20 0.04 1.17 ? 0.20 1.65 ? 0.20 0.19 
Wetness 1.53 ? 0.16 1.78 ? 0.16 0.40 1.66 ? 0.16 1.66 ? 0.16 1.00 
Firmness 1.40 ? 0.21 1.57 ? 0.21 0.66 1.52 ? 0.21 1.44 ? 0.21 0.83 
L* 59.88 ? 1.36 59.79 ? 1.36 0.97 59.64 ? 1.36 60.04 ? 1.36 0.87 
a* 10.82 ? 0.61 10.88 ? 0.61 0.96 10.99 ? 0.61 10.71 ? 0.61 0.79 
b* 18.88 ? 0.91 15.78 ? 0.91 0.07 16.21 ? 0.91 18.45 ? 0.91 0.07 
% FFL 50.52 ? 1.04 56.14 ? 1.04 0.006 53.14 ? 1.04 53.52 ? 1.04 0.006 
FFL, kg 40.77 ? 2.36 44.72 ? 2.36 0.05 42.61 ? 2.36 42.87 ? 2.36 0.89 
 
 
 
 
 
51 
 
 
Table 10. LS Means ?  SEM for Treatment Effects of Feeding PJC to Growing / Finishing Pigs on Drip Loss, Marinade Uptake, 
Marinade Cook Loss, WBS, and Cook Loss 
 
 
 
 
 
 
 
 Treatment  
 Control 0.5% PJC 1.0% PJC 2.9% PJC P>F 
% Drip Loss 0.79 ? 0.25 1.17 ? 0.25 0.92 ? 0.22 1.50 ? 0.23 0.19 
% Marinade 
Uptake 30.43 ? 8.90 37.25 ? 8.90 31.08 ? 7.89 22.02 ? 8.24 0.67 
% Marinade 
Cook Loss 39.14 ? 2.97 40.25 ? 2.97 37.22 ? 2.63 33.87 ? 2.75 0.41 
WBS, kg 1.53 ? 0.24 1.33 ? 0.24 1.21 ? 0.21 1.51 ? 0.22 0.10 
%  Cook Loss 16.88 ? 1.56 13.87 ? 1.56 13.27 ? 1.38 15.64 ? 1.44 0.34 
52 
 
 
 
 
 
Table 11. LS Means ?  SEM for Sex and Harvest Group Effects of Feeding PJC to Growing / Finishing Pigs on Drip Loss, Marinade 
Uptake, Marinade Cook Loss, WBS, and Cook Loss 
 Sex  Harvest Group  
 Barrow Gilt P>F 1 2 P>F 
% Drip Loss 
 0.54 ? 0.26 1.64 ? 0.26 0.03 0.87 ? 0.26 1.33 ? 0.26 0.32 
% Marinade Uptake 
 34.40 ? 9.13 25.99 ? 9.13 0.61 22.05 ? 9.13 38.34 ? 9.13 0.33 
% Marinade Cook 
Loss 
 
39.30 ? 3.04 35.94 ? 3.04 0.55 33.19 ? 3.04 42.04 ? 3.04 0.12 
WBS, kg 
 1.27 ? 0.24 1.51 ? 0.24 0.22 1.43 ? 0.24 1.15 ? 0.24 0.02 
% Cook Loss 18.08 ? 1.60 11.75 ? 1.60 0.04 12.06 ? 1.60 17.77 ? 1.60 0.06 
  
 
53 
 
 Control 0.5% PJC 1.0% PJC 2.9% PJC P > F 
C 8:0 0.13 ? 0.04 0.08  ? .04 0.16  ? 0.04 0.05  ? 0.04 0.31 
C 10:0 0.16  ? 0.07 0.20  ? 0.06 0.14  ? 0.06 0.08  ? 0.07 0.58 
C 11:0 0.27  ? 0.06 0.23 ? 0.06 0.14  ? 0.06 0.16  ? 0.06 0.43 
C 12:0 0.30  ? 0.07 0.11  ? 0.07 0.22  ? 0.07 0.30  ? 0.07 0.13 
C 13:0 1.17  ? 0.10 1.31  ? 0.97 1.25  ? 0.09 1.24  ? 0.10 0.82 
C 14:0 0.16  ?0.07 0.15  ?0.06 0.14  ? 0.06 0.14  ? 0.06 0.99 
C 14:1 1.46  ? 0.19 1.77  ? 0.18 1.54  ? 0.18 1.52  ? 0.18 0.65 
C 15:0 0.11  ? 0.05 0.15  ? 0.05 0.19  ? 0.05 0.10  ? 0.05 0.58 
C 16:0 22.15 ? 0.55 21.7 ? 0.53 21.60 ? 0.53 22.17 ? .55 0.81 
C 16:1 4.21 ? 0.18 4.78 ? 0.17 4.27 ? 0.17 4.53 ? 0.18 0.1 
C 17:0 1.48 ? 0.21 1.52 ? 0.20 1.41 ? 0.20 1.68 ? 0.21 0.81 
C 17:1 9.61 ? 0.19 9.00 ? 0.18 9.52 ? 0.18 9.18 ? 0.18 0.09 
C 18:0 0.15 ? 0.05 0.14 ? 0.05 0.19 ? 0.05 0.08 ? 0.05 0.53 
C 18:1 N9T 0.64 ? 0.05 0.67 ? 0.04 0.59 ? 0.04 0.65 ? 0.05 0.59 
C 18:1 N9C 38.94 ? 1.22 37.27 ? 1.18 38.13 ? 1.18 37.79 ? 1.22 0.8 
C 18:2 N6T 0.05 ? 0.05 0.19 ? 0.04 0.01 ? 0.04 0.11 ? 0.05 0.03 
C 18:2 N6C 11.80 ? 0.86 12.48 ? 0.83 12.89 ? 0.83 12.23 ? 0.86 0.83 
C 20:0 0.47 ? 0.07 0.53 ? 0.07 0.51 ? 0.07 0.62 ? 0.07 0.55 
C 18:3 N6 0.19 ? 0.06 0.19 ? 0.05 0.27 ? 0.06 0.29 ? 0.06 0.56 
C 20:1 0.98 ? 0.07 0.88 ? 0.06 0.97 ? 0.06 0.92 ? 0.07 0.66 
C 18:3 N3 0.10 ? 0.03 0.07 ? 0.03 0.15 ? 0.03 0.05 ? 0.03 0.14 
C 21:0 0.11 ? 0.06 0.29 ? 0.06 0.21 ? 0.06 0.21 ? 0.06 0.22 
C 20:2 0.34 ? 0.06 0.47 ? 0.06 0.38 ? 0.06 0.43 ? 0.6 0.45 
C 22:0 0.60 ? 0.11 0.44 ? 0.10 0.61 ? 0.10 0.67 ? 0.11 0.5 
C 20:3 N6 0.16 ? 0.06 0.24 ? 0.06 0.13 ? 0.06 0.19 ? 0.06 0.63 
C 20:4 N6 2.86 ? 0.33 2.99 ? 0.32 2.83 ? 0.32 2.92 ? 0.33 0.99 
C 20:3 N3 0.09 ? 0.08 0.23 ? 0.07 0.10 ? 0.07 0.14 ? 0.08 0.5 
C 20:4 N6 2.86 ? 0.33 2.99 ? 0.32 2.83 ? 0.32 2.92 ? 0.33 0.99 
C 23:0 0.05 ? 0.03 0.11 ? 0.03 0.05 ? 0.03 0.02 ? 0.03 0.31 
C 22:2 0.03 ? 0.01 0.03 ? 0.01 0.00 ? 0.01 0.01 ? 0.01 0.15 
C 20:5 N3 0.04 ? 0.02 0.09 ? 0.02 0.00 ? 0.02 0.02 ? 0.02 0.06 
C 24:1 0.24 ? 0.10 0.44 ? 0.09 0.16 ? 0.09 0.21 ? 0.10 0.17 
C 22:6 N3 0.93 ? 0.16 1.25 ? 0.15 1.27 ? 0.15 1.30 ? 0.16 0.35 
Total 99.99 ? 0.01 1.00.01 ? 0.01 100.00 ? 0.01 100.01 ? 0.01 0.39 
SFA 27.31 ? 0.36 26.96 ? 0.35 26.83 ? 0.35 27.52 ? 0.36 0.5 
MUFA 56.09 ? 1.09 54.81 ? 1.06 55.16 ? 1.06 54.79 ? 1.09 0.83 
PUFA 16.60 ? 1.33 18.23 ? 1.28 18.01 ? 1.29 17.68 ? 1.33 0.82 
Ratio 0.61 ? 0.06 0.68 ? 0.05 0.67 ? 0.05 0.65 ? 0.06 0.79 
N6 15.07 ? 1.21 16.09 ? 1.17 16.12 ? 1.17 15.74 ? 1.21 0.92 
N3 1.16 ? 0.18 1.64 ? 0.17 1.51 ? 0.17 1.50 ? 0.18 0.28 
N6N3 13.64 ? 1.43 11.33 ? 1.38 11.83 ? 1.38 11.11 ? 1.43 0.61 
Table 12. LS Means ? SEM for Effects of feeding PJC to Growing / Finishing Pigs on Fatty Acids 
54 
 
Table 13. LS Means ? SEM for Sex Effects of feeding PJC to Growing / Finishing Pigs on FA 
 
 
 
 
  
 Barrows Gilts P > F C 8:0 0.14 ? 0.03 0.07 ? 0.03 0.14 
C 10:0 0.13 ? 0.05 0.16 ? 0.05 0.57 
C 11:0 0.19 ? 0.04 0.21 ? 0.04 0.75 
C 12:0 0.26 ? 0.05 0.20 ? 0.05 0.39 
C 13:0 1.22 ? 0.07 1.27 ? 0.07 0.63 
C 14:0 0.13 ? 0.05 0.17 ? 0.05 0.61 
C 14:1 1.43 ? 0.13 1.72 ? 0.13 0.15 
C 16:0 22.77 ? 0.39 21.04 ? 0.39 0.01 
C 16:1 4.47 ? 0.13 41.42 ? 0.13 0.77 
C 17:0 1.37 ? 0.15 1.67 ? 0.15 0.18 
C 17:1 9.60 ? 0.13 9.05 ? 0.13 0.01 
C 18:0 0.17 ? 0.04 0.12 ? 0.04 0.36 
C 18:1 N9T 0.59 ? 0.03 0.68 ? 0.03 0.06 
C 18:1 N9C 38.65 ? 0.86 37.41 ? 0.86 0.33 
C 18:2 N6T 0.07 ? 0.03 0.12 ? 0.03 0.34 
C 18:2 N6C 11.75 ? 0.61 12.95 ? 0.61 0.19 
C 20:0 0.51 ? 0.05 0.56 ? 0.05 0.45 
C 18:3 N6 0.22 ? 0.04 0.25 ? 0.04 0.57 
C 20:1 0.94 ? 0.05 0.94 ? 0.05 0.95 
C 18:3 N3 0.08 ? 0.02 0.10 ? 0.02 0.58 
C 21:0 0.17 ? 0.04 0.24 ? 0.04 0.26 
C 20:2 0.35 ? 0.41 0.46 ? 0.04 0.07 
C 22:0 0.52 ? 0.08 0.64 ? 0.08 0.29 
C 20:3 N6 0.16 ? 0.04 0.20 ? 0.04 0.53 
C 20:4 N6 2.29 ? 0.23 3.21 ? 0.23 0.08 
C 20:3 N3 0.14 ? 0.05 0.14 ? 0.05 0.98 
C 20:4 N6 2.59 ? 0.23 3.21 ? 0.23 0.08 
C 23:0 0.05 ? 0.02 0.05 ? 0.02 0.93 
C 22:2 0.01 ? 0.01 0.02 ? 0.01 0.39 
C 20:5 N3 0.03 ? 0.02 0.04 ? 0.02 0.88 
C 24:1 0.21 ? 0.07 0.32 ? 0.07 0.29 
C 22:6 N3 0.97 ? 0.11 1.41 ? 0.11 0.01 
Total 99.99 ? 0.004 100.00 ? 0.004 0.29 
SFA 27.74 ? 0.26 26.58 ? 0.26 0.01 
MUFA 55.89 ? 0.77 54.54 ? 0.77 0.24 
PUFA 16.37 ? 0.94 18.89 ? 0.94 0.78 
Ratio 0.59 ? 0.04 0.72 ? 0.04 0.04 
N6 14.79 ? 0.86 16.73 ? 0.86 0.13 
N3 1.22 ? 0.13 1.68 ? 0.13 0.02 
N6N3 13.02 ? 1.01 10.93 ? 1.01 0.17 
55 
 
 
Table 14. LS Means ? SEM for Effects of Feeding PJC to Growing / Finishing Pigs on Initial Juiciness, Sustained  Juiciness, Initial 
Tenderness, Sustained Tenderness, Pork Flavor, and Off Flavor 
 
aScored on an 8-point scale (1 = extremely dry, 8 = extremely juicy) 
bScored on an 8-point scale (1 = extremely tough, 8 = extremely tender) 
cScored on an 8-point scale (1 = extremely bland, 8 = extremely intense) 
dScored on an 8-point scale (1 = no off flavor, 8 = extreme off flavor) 
 
Variable Control 0.5% PJC 1.0% PJC 2.9% PJC P > F 
Initial Juicinessa 5.47 ? 0.32 5.62 ? 0.32 5.32 ? 0.28 4.82 ? 0.30 0.3 
Sustained Juicinessa 5.20 ? 0.34 5.42 ? 0.34 5.06 ? 0.30 4.66 ? 0.31 0.42 
Initial Tendernessb 5.06 ? 0.35 5.67 ? 0.35 4.97 ? 0.31 4.91 ? 0.32 0.37 
Sustained Tendernessb 4.87 ? 0.41 5.40 ? 0.41 4.86 ? 0.36 4.59 ? 0.38 0.56 
Pork Flavorc 4.99 ? 0.15 4.98 ? 0.15 4.89 ? 0.13 4.88 ? 0.14 0.91 
Off Flavord 1.18 ? 0.09 1.19 ? 0.09 1.34 ? 0.08 1.16 ? 0.08 0.38 
56 
 
 
 
 
 
Table 15. LS Means ? SEM for Sex and Harvest Group Effects of Feeding PJC to Growing / Finishing Pigs on Initial Juiciness, 
Sustained  Juiciness, Initial Tenderness, Sustained Tenderness, Pork Flavor, and Off Flavor 
 
aScored on an 8-point scale (1 = extremely dry, 8 = extremely juicy) 
bScored on an 8-point scale (1 = extremely tough, 8 = extremely tender) 
cScored on an 8-point scale (1 = extremely bland, 8 = extremely intense) 
dScored on an 8-point scale (1 = no off flavor, 8 = extreme off flavor) 
 
 
 Sex Harvest Group 
Variable Barrow Gilt P > F 1 2 P > F 
Initial Juicinessa 5.17 ? 0.33 5.44 ? 0.33 0.65 5.46 ? 0.33 5.16 ? 0.33 0.62 
Sustained Juicinessa 5.20 ? 0.34 4.97 ? 0.34 0.71 5.07 ? 0.34 5.10 ? 0.34 0.96 
Initial Tendernessb 4.97 ? 0.35 5.34 ? 0.35 0.57 5.20 ? 0.35 5.11 ?  0.35 0.89 
Sustained Tendernessb 4.92 ? 0.42 4.94 ? 0.42 0.97 4.92 ? 0.42 4.94 ?  0.42 0.97 
Pork Flavorc 5.03 ? 0.15 4.85 ? 0.15 0.52 5.00 ? 0.15 4.87 ?  0.15 0.63 
Off Flavord 1.22 ? 0.09 1.21 ? 0.09 0.94 1.26 ? 0.09 1.18 ?  0.09 0.62 
57 
 
 
Figure 1. Day x Treatment Interaction of Feeding PJC to Growing / Finishing Pigs on Anaerobic Plate Count 
 
 
 
0
1
2
3
4
5
6
7
8
9
0 1 7 14 28 56 Pre-Harvest Post-Harvest
Swab
CFU
 Control
0.5% PJC
1.0% PJC
2.9% PJC
Day 
58 
 
 
Figure 2. Day x Treatment Interaction of Feeding PJC to Growing / Finishing Pigs on Aerobic Plate Count 
 
 
 
0
1
2
3
4
5
6
7
8
9
0 1 7 14 28 56 Pre-Harvest Post-Harvest
Swab
CFU
 Control
0.5% PJC
1.0% PJC
2.9% PJC
Day 
59 
 
 
Figure 3. Day x Treatment Interaction of Feeding PJC to Growing / Finishing Pigs on VRBA Count 
 
 
0
1
2
3
4
5
6
7
8
0 1 7 14 28 56 Pre-Harvest Post-Harvest
Swab
CFU
 Control
0.5% PJC
1.0% PJC
2.9% PJC
Day 
60 
 
      Figure 4. Effects of Feeding PJC to Growing / Finishing Pigs on Ham pH 
 
 
      Figure 5. Effects of Feeding PJC to Growing / Finishing Pigs on Loin pH 
 
 
 
5.5
5.7
5.9
6.1
6.3
6.5
6.7
30m 45m 180m 360m Ultimate
Control 0.5% PJC 1.0% PJC 2.9% PJC
5.5
5.7
5.9
6.1
6.3
6.5
6.7
30m 45m 180m 360m Ultimate pH
Control 0.5% PJC 1.0% PJC 2.9% PJC
pH
  
pH
  
61 
 
Figure 6. Sex and Harvest Group Effects of Feeding PJC to Growing / Finishing Pigs on 
Ham pH 
 
 
Figure 7. Sex and Harvest Group Effects of Feeding PJC to Growing / Finishing Pigs on 
Loin pH 
5.5
5.7
5.9
6.1
6.3
6.5
6.7
30m 45m 180m 360m Ultimate
Barrow
Gilt
Harvest Group 1
Havest Group 2
5.5
5.7
5.9
6.1
6.3
6.5
6.7
30m 45m 180m 360m Ultimate
Barrow
Gilt
Harvest Group 1
Havest Group 2
pH
  
pH
 
 
62 
 
 
 
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72 
 
 
 
Appendix A 
48 Hour Drip Loss 
National Pork Producers Council Publication. 2000. Pork Composition and Quality 
Assessment Procedures. Des Moines, IA 
1. Post-rigor, fresh muscle of choice (usually the longissimus) is sectioned 
perpendicular to fiber orientation. Each section show be 4 cm think and taken 
from a standards location. Duplicate analysis from adjacent section is 
recommended.  
 
2. Using a stainless steel coring device, 4 cm in diameter, cut sample from center of 
the section. The sample should weigh at least 40 g to 50 g. It is very important 
that the weight be standardized within a reasonable range (10g) to maintain a 
constant surface area to volume ratio. Small samples, (20 g) as compared to large 
ones (75 g), will have larger surface area/volume ratio and, thus, will lose 
proportionally more fluids.  
3. Weigh cored sample to neatest 0.01 g on a balance.  
 
4. Suspend sample on a hook (S-hook or fish hook works well) and contain it in a 
plastic bag, freezer container, or wax-coated box. Insure that container does not 
touch the sample and that the humidity and airflow remain constant. The 
temperature needs to be constant (usually 2-4?C). It is important that the samples 
are fresh and not frozen.  
 
 
5. Keep sample at 4?C for 48 hr. Other times such as 24 or 72 hr are appropriate to 
insure differences in water holding capacity for a given test. However, the 48 hr is 
recommended and should be used when comparing results with other laboratories.  
 
6. After 48 hr, remove sample from hook, blot (do not squeeze) remaining surface 
fluids twice with paper toweling, and weigh to nearest 0.1 g. 
 
73 
 
 
7. Percentage drip is calculated by dividing loss in weight (due to drip) by initial 
weight x 100. Duplicate values should agree to < 10% 
 
8. For longissimus sample taken at 24 hr postmortem suspend for hr at 4?C the 
following % drip loss values serve as guidelines for establishing quality 
category*: 
a. RSE and PSE : > 6% 
b. RFN and DFD: < 6% (DFD mostly < 2%).  
*DFD = Dark, Firm, and Dry; RFN = Reddish-pink, Firm, and Nonexudative; RSE = 
Reddish-pink, Soft, and Exudative; PSE = Pale, Soft and Exudative.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
74 
 
 
Appendix B 
Marinade Uptake 
National Pork Producers Council Publication. 2000. Pork Composition and Quality 
Assessment Procedures. Des Moines, IA 
 
1. Remove external fat from muscle. Subsequently, grin meat through 6.4-mm (1/4-
inch) plate. Conduct all measurements in triplicate.  
 
2. Weigh and number 50 ml centrifuge tubes (without cap). Record the weight of 
tubes to second decimal place (0.01 g). 
 
3. Weigh 6.00 ? 0.01g of ground meat into each centrifuge tube. 
 
 
4. Add 10 ml of reagent bugger (3.5% NaCl = NaCl in 1 liter of water). 
 
5. Place scewcap on tightly and shake gently until samples break apart.  
 
6. Vigorously shake an additional 15 seconds. 
 
7. Put tubes in water bath for 30 minutes ?incubation? at 25?C. 
 
8. After incubation, centrifuge for 20 minutes at 3000 rpm (= 800 x g) 
 
9. Remove cap and put tube upside down to drain water for 5 minutes.  
 
10. Weigh samples and tubes (without screw cap), and record to the second decimal 
place (0.01 g). 
 
Marinade Uptake = 
(weight tube and meat, after incubation at 25?) ? (initial weight of tube and meat) / 6.00 g 
x 100 
 
75 
 
 
Appendix C 
Marinade Cook Loss 
National Pork Producers Council Publication. 2000. Pork Composition and Quality 
Assessment Procedures. Des Moines, IA 
1. Loosely cap drained tube an place rack of tubes into 80?C (preheated) water bath 
for 20 minutes (time sharply).  
2. Remove and drain cook-out water and completely cool samples to 20-22?C. 
3. Weigh the tube and meat (without screw cap) and record weight to 0.01 g. 
4. Discard tubes and sample 
Marinade Cook Loss = 
(weight tube and meat, after cooking) ? (initial weight of tube and meat) / 6.00 g x 100 
 
 
 
 
 
 
 
 
 
 
76 
 
 
Appendix D 
Thiobarbituric Reactive Substances Assay 
Wang, B., Pace, R. D., Dessai, A. P., Bovell-Benjamin, A., Phillips, B. 2002. Modified 
extraction method for determining 2-thiobarbituric acid values in meat with increase 
specificity and simplicity. J. Food Sci. 67:2833-2836. 
 
A. Solutions  
a. TCA Extraction solution  
7.5% (w/v) trichloroacetic acid  
0.1% (w/v) EDTA  
0.1% (w/v) Propyl Gallate  
b. 80 mM TBA solution  
1.15 g Thiobarbituric acid into 100 mL ddH2O  
 
c. Standard Solution  
Make a 1 mM solution by adding 240 ?L of tetraethoxypropane to 1L  
B. Standards  
a. Dilute 1mM stock solution to 80 nM /L  
b. Then make standards following the table below in individual tubes 
 
C. Sample preparation and extraction procedure  
a. Mince meat sample and weigh out 5 g  
b. Place meat into a 50 mL centrifuge tube and add 15 mL TCA Extraction 
solution 
mg / kg TEP  TEP (?L)  TCA (?L)  Pipette Setting  
0  0  2000  1000 x 2  
2  50  1950  975 x 2  
4  100  1900  950 x 2  
6  150  1850  925 x 2  
8  200  1800  900 x 2  
10  250  1750  875 x 2  
20  500  1500  750 x 2  
30  750  1250  625 x 2  
77 
 
 
c. Homogenize meat for 20-30 sec using a blender 
d. Place lid back on centrifuge tube 
e. Centrifuge at 1,500 x g for 15 min  
f. Remove from centrifuge and filter through No. 4 Whatman paper  
D. Incubation and Reading  
a. Load 96-well microplate  
b. Each sample should be loaded in triplicate with 125 ?L / well (See diagram 
below for details) 
 1 2 3 4 5 6 7 8 9 10 11 12 
A 0 0 0 A A A I I I Q Q Q 
B 2 2 2 B B B J J J R R R 
C 4 4 4 C C C K K K S S S 
D 6 6 6 D D D L L L T T T 
E 8 8 8 E E E M M M U U U 
F 10 10 10 F F F N N N V V V 
G 20 20 20 G G G O O O W W W 
H 30 30 30 H H H P P P X X X 
 
c. After sample are loaded, pipette 125 ?L of TBA Solution into each well  
d. Incubate for 130 min at 40o C  
e. Remove plates from incubator and read at 540 nm on plate reader 
 
 
 
 
 
78 
 
Appendix E 
Fatty Acid Methyl Esters 
O?Fallon, J. V., Busboom, J. R., Nelson, M. L., Gaskins, C. T. 2007. A direct method for 
fatty acid methyl ester synthesis: Application to wet meat tissues, oils, and feedstuffs. J. 
Anim. Sci. 85:1511-1521. 
 
A. Solutions and Chemicals  
a. Hexane  
b. Methanol (MeOH)  
c. 10 N KOH  
d. 24 N H2SO4  
 
B. Direct Fatty Acid Methylation  
a. Mince meat sample and weigh out 1 g  
b. Place 1 g meat into a 16 mL screwtop tube  
c. Add 5.3 mL of MeOH, 0.7 mL of KOH and standard to meat sample in tube. 
Place cap on tube and place in water bath at 55o C. If waterbath has a shaker attachment, 
turn shaker attachment on to desired setting. If there is no shaker attachment, vortex 
samples for 5 s every 20 min. Incubate for 90 min.  
 
d. After incubation, place samples in cold tap water and allow to cool to below 
room temperature.  
 
e. After cooling, add 0.58 mL of 24 N H2SO4. Mix tube by inversion and make 
sure K2SO4 precipitate is present. Place tube back in water bath and incubate for 90 min 
at 55o C. If there is no shaker attachment, vortex samples for 5 s every 20 min.  
 
f. Repeat step d.  
g. After cooling, add 3 mL of hexane and vortex for 5 min.  
h. Centrifuge tubes for 5 min at 1,500 x g.  
i. Remove hexane layer and place in fatty acid vial.  
j. Place fatty acid vials in freezer until time of analysis 
 
79 
 
Appendix F 
Trained Sensory Evaluation Form 
 
 
Juiciness 
 
Tenderness 
 
Flavor Intensity 
 
Off Flavor 
Intensity 
 
Off Flavor 
Descriptor 
8= Extremely 
Juicy 
8= Extremely 
Tender 
8= Extremely 
Intense Pork 
8= Extremely Off 
Flavor 8= Metallic 
7= Very Juicy 7= Very Tender 7= Very Intense Pork 7= Intense Off Flavor 7= Salty  
6= Moderately 
Juicy 
6= Moderately 
Tender 
6= Moderately 
Intense Pork 
 
6= Very Off 
Flavor 
6= Livery 
 
5= Slightly Juicy 5= Slightly Tender 5= Slightly Intense Pork 5= Moderate Off Flavor 5= Grassy  
4= Slightly Dry 4= Slightly Tough 4= Slightly Bland 4= Modest Off Flavor 4= Bitter  
3= Moderately 
Dry 
3= Moderately 
Tough 
3= Moderately 
Bland 
3= Small Off 
Flavor 
3= Bloody 
 
2= Very Dry 2= Very Tough 2= Very Bland 2= Slight Off Flavor 2= Rancid  
1= Extremely Dry 1= Extremely Tough 1= Extremely Bland 1= No Off Flavor 1= Other -     Explain 
 
Sample 
Number 
Initial 
Juiciness 
Sustained 
Juiciness 
Initial 
Tenderness 
Sustained 
Tenderness 
Pork 
Flavor 
Intensity 
Off 
Flavor 
Intensity 
Off Flavor 
Descriptor 
        
        
        
        
        
        
        
Name  Date Project