Evaluation of Lactic Acid and Sodium Metasilicate against Pathogens of Concern on Fresh and Deli Meats
Type of Degreedissertation
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Lactic acid and sodium metasilicate have been used in meat processing facilities as antimicrobial compounds. Their uses vary from carcasses rinses to ready to eat product applications at a variety of concentrations and temperatures. Utilizing these antimicrobials in different stages during meat processing may assist in the reduction of the risk of pathogenic microorganisms. The purpose of this study was to determine optimum concentrations and temperatures of application of lactic acid and sodium metasilicate for pathogen reduction on beef bottom round muscles. Using this information, optimal concentrations and temperatures were then applied to fresh pork and processed deli meats in addition to fresh beef. Four consecutive studies were conducted. In the first study, lactic acid (LA) was applied at 1, 2, 3, and 4% (LA1, LA2, LA3, and LA4) and sodium metasilicate (SM) was applied to fresh beef bottom rounds at 2, 3, 4, and 5% (SM2, SM3, SM4, and SM5) levels. In the next study, LA4 (v/v), SM4 (w/v), the combination of the two solutions (LASM), and distilled water (control) were applied to fresh beef bottom rounds at 4, 25, and 60 °C. During the third study, LA4, SM4, and distilled water were applied to fresh beef and pork lean muscle and roast beef, ham, and turkey deli meats that were manufactured at the Lambert Powell Meat Laboratory without the use of antimicrobial solutions. All data were analyzed using the PROC MIXED procedure of SAS and Tukey pairwise comparisons, where appropriate (P > 0.05). LA and SM reduced (P < 0.05) the bacterial load of all the meat samples. Temperature of application had no effect (P > 0.05) on bacterial counts in any of the treatments. LA or SM alone were more effective (P < 0.05) in reduction of microbes than when used together (LASM). The control treatment resulted in higher microbial counts regardless of inoculum or species than either the LA or SM treatments (P < 0.01). Treatments including a hot water dip decreased the bacterial load of samples in comparison to those that did not receive the post packaging lethality treatment (P < 0.01). Regardless of hot water dip treatments, there were no differences among treatment groups in regards to microbial counts (P > 0.73). SM4 and LA4 were determined to be the lowest concentrations most effective against all microorganisms. Meat processors can apply LA or SM at refrigeration temperatures with the same benefits as applying them at a higher temperature. Both lactic acid and sodium metasilicate can be applied to fresh beef and pork as an effective hurdle technology in the fight for food safety. Treating deli meats with lactic acid or sodium metasilicate did not reduce L. monocytogenes loads. However, adding a post-packaging lethality treatment was able to minimize overall microbial contamination.