89D-30 |
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S. A. IBRAHIM1, W. M. Brown, Jr.1, and C. W. Seo2. (1) Food Science & Nutrition, North Carolina A&T State Univ., Dept. of Human Environment & Family Sciences, 171-B Carver Hall, Greensboro, NC 27411-1064, (2) Food Science & Nutrition Program, North Carolina A&T State Univ., Dept. of Human Environment & Family Sciences, 171-B Carver Hall, Greensboro, NC 27411-1064 Escherichia coli O157:H7 is a leading cause of bacterial food borne outbreaks and is responsible for approximately 73,500 cases of food borne illness per year. The presence and survival of E. coli on/in red meat during storage continues to be a public health concern. Numerous studies have shown that chemical washing can effectively decontaminate red meat carcasses. But, because of the possible undesired chemical reactions affecting the quality of the meat, other treatment alternatives may be preferred. Recent research has shown that Lactobacillus reuteri has antimicrobial effect against pathogenic bacteria including E coli O157:H7. The objective of this study was to determine if immersing E. coli inoculated meat sample in a Lactobacillus reuteri supernatant would significantly affect the survival and growth of E. coli O157:H7. Cube steak samples (100g) were inoculated individually with different strains of E. coli O157: H7 (944, 380, E0019, cider, F4546, H1730) to achieve a final inoculum level of 2 log cfu/ml. The meat samples were then refrigerated for 12 hr at 4oC to allow time for the bacterial cells to adhere on the meat surface. The samples were then washed with a lactobacillus supernatant (200ml) for two min and then placed in sterile bags and stored for 37oC. Samples were withdrawn at 0, 12, 24 and 48hr sampling periods and the appropriate dilutions were plated on included trypticase soy agar (TSA), sorbitol MacConkey agar (SMAC), and Eosin methylene blue agar (EMB) to determine populations of bacteria during the storage period. Our results showed that in control meat samples, the population of E. coli O157:H7significantly increased from the initial level of 2.00 log cfu/g to 7.1 to 8.0 after 2 days. In the treated samples, the microbial population reached 5.6- 6.1 log cfu/g. The treated meat samples showed reduced bacterial populations by 1.2 to 1.9 log CFU/g. These results suggest that a lactobacillus supernatant has potential as an antimicrobial agent and should be investigated further as a food additive to increase the biosafety of consumable food products.
Session 89D, Food Microbiology: Antimicrobial effects on foodborne microorganisms
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |