89D-11 |
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O. Z. MUTAMBA1, S. A. Ibrahim1, C. W. Seo1, M. M. Salameh1, and H. Yang2. (1) Food Science & Nutrition Program, North Carolina A&T State Univ., Dept. of Human Environment & Family Sciences, 171-B Carver Hall, Greensboro, NC 27411-1064, (2) Dept. of Human Environment & Family Sciences, North Carolina A&T State Univ., 161 Carver Hall, Greensboro, NC 27411 Foodborne illness resulting from the consumption of contaminated food products with pathogenic bacteria has been of great concern to public health. Controlling pathogenic bacteria would reduce foodborne outbreaks and assure consumers a continuing safe, wholesome and nutritious food supply. The antimicrobial properties of organic acids have been well documented. In addition, copper sulfate has been shown to have some antimicrobial activities against and may have great potential as an antimicrobial agent. The objective of this study was to investigate the effect of lactic acid alone or in combination with caffeine and copper on the survival and growth of Escherichia coli O157: H7 in laboratory medium. Five strains of E. coli O157: H7 (F4546, 944, cider, E0019, H1730) were used in this study. Batches of LB broth with 0.1% lactic acid alone or in combination with 0.25% caffeine and 500ml of cupric sulfate were prepared and sterilized at 121° C for 15minutes. Individual strain of E. coli O157: H7 was inoculated into the sterilized LB broth and incubated at 37° C for 24 hours. Growth was monitored by measuring turbidity using a spectrophotometer (OD 610nm) every two hours. This experiment was replicated four times in a randomized block design. When used alone, lactic acid reduced the growth of E. coli 0157:H7. Lactic acid in combination with caffeine caused total growth inhibition of E.coli 0157:H7. When copper was used alone, little or no growth inhibition was observed, however, combination of lactic acid and copper caused significant growth inhibition when compared to lactic acid alone or the control samples. When copper was combined with caffeine only, the inhibition of growth was similar to that of lactic acid alone. The combination of all three chemicals, lactic acid, caffeine and copper did not further inhibit the growth of E.coli 0157:H7. Our results show that lactic acid in combination with caffeine or copper can be used as anitmicrobial agents in the preservation of food to inhibit the growth of E.coli 0157:H7.
Session 89D, Food Microbiology: Antimicrobial effects on foodborne microorganisms
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |