Effect of Concrete Sealant on Survival of Foodborne Bacteria in Processing Environments

Abstract

Concrete sealants have been frequently used in the food industry to increase durability of concrete and decrease maintenance costs. In an attempt to associate these desirable properties of topical concrete sealants to a necessity in the food industry (reducing and controlling microbial levels), BioSealed for Concrete™ was created. This study was then designed to determine the efficacy of this product to prevent bacterial attachment, colonization, and antimicrobial effect against multiple microorganisms (Salmonella, Listeria, Clostridium and Bacillus) on concrete. Cement blocks were divided into four different treatment groups: A) No Biosealed application, B) Biosealed applied before inoculation, C) Biosealed applied after inoculation, or D) Biosealed applied before and after inoculation. The cultures were prepared by inoculating microorganisms into individual brain and heart infusion broth (BHI) and incubating them at their optimum growth temperature for 24 h. Cement blocks were inoculated by submerging in BHI broths containing one of the bacteria tested and incubated for 24 h (ca. 109 CFU/ ml). External surfaces of the inoculated blocks were swabbed using sterile swabs and placed in 10 mL peptone water (PW). The cement blocks were broken in half and interior surfaces were swabbed to determine bacterial levels. A completely randomized design was used to assign concrete blocks to the four treatment groups. Three replications of this experiment were performed and averages of the survival populations (log10 CFU/ sq. cm) of various bacteria were analyzed using analysis of variance (ANOVA) with SAS PROC GLM procedures (2002-03 SAS 9.1 Institute, Gary, NC). Statistical significance was reported at a P-value of less than or equal to 0.05 (P<0.05). BioSealed for ConcreteTM proved to be a potent antimicrobial with immediate bactericidal effects that has potential to facilitate biofilm removal. Results from this study indicate that BioSealed for ConcreteTM can be used as an alternative in food processing plants that have persistent and recurrent biofilm problems. Although antimicrobial capabilities of BioSealed for ConcreteTM were shown in this study, its use should not be substituted for good manufacturing practices and/ or efficient cleaning and sanitizing procedures. The factors required for biofilm formation are still unknown, and although some progress has been made in this area, understanding the full mechanism of colonization to inert surfaces is a key factor on the process of attempting to prevent its occurrence.