100A-18 |
Efficacy of common sanitizers on pathogen biofilms on stainless steel surface |
T. KIM1, T. C. Chen2, and J. L. Silva1. (1) Food Science and Technology, Mississippi State University, Mississippi State, MS 39762, (2) Poultry Science, Mississippi State University Biofilms formed on food equipment and food contact surfaces are very difficult to remove and are proven sources of product contamination. Much work is needed to discern individual pathogen biofilm formation and resistance to sanitizers. Objective of this study was to investigate the efficacy of commonly used sanitizers on selected pathogen biofims on stainless steel surface. Biofilms of Listeria monocytogens, Escherichia coli O157:H7, and Salmonella typhimurium on stainless steel(SS, type 304) surface were prepared separately by incubating SS chips (2 x2 cm2) in tryptic soy broth containing suspended pathogen cells at 37 °C for 3 and 6 days. The incubated SS chips were washed with sterile phosphate buffer saline to remove unattached cells and treated with 10, 30, and 50 ppm of chlorine, quaternary ammonium(quats), and peroxyacetic acid solutions separately for 1 min. Total pathogen counts on the treated and untreated biofilms were achieved by swabbing the SS surfaces with sterile cotton swabs. Experiments were quadruplicated and data were statistically analyzed. Regardless of pathogen type, counts on 6-day biofilms were higher than those of the 3-day biofilms. No apparent difference in sanitizing efficacy was observed among biofilms by the three selected sanitizers at 10 and 30 ppm. No pathogens were isolated from biofilms treated with the tested sanitizers at 50 ppm, except on 6 day S. typhimurium biofilms treated with quats. In general, 6-day biofilms were more resistant than their 3-day counterparts. Common sanitizers used at 50 ppm effectively destroyed Escherichia coli O157:H7, and Salmonella typhimurium biofilms except for quats on 6-day S. typhimurium biofilms.
Session 100A, Food Microbiology: General II
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