89D-24 |
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V. C.-H. WU1, X. Qiu2, and A. A. Bushway1. (1) Dept. of Food Science & Human Nutrition, Univ. of Maine, 5735 Hitchner Hall, Orono, ME 04469-5735, (2) Food Science and Human Nutrition, 5735 Hitchner Hall Cranberry contains various bioactive compounds such as proanthocyanidins, flavonols, benzoic acid and other phenolics which have antioxidant activities and potential health benefits. Previous studies have indicated these compounds, especially phenolics, have antimicrobial activities. We investigated the antimicrobial effects of cranberry concentrate on four foodborne pathogens, Escherichia coli O157:H7, Listeria monocytogenes, Salmonella Typhimurium , and Staphylococcus aureus in both water and growth media. Cranberry concentrate at five concentration levels (0, 2.5, 5.0, 7.5, and 10% w/v) were prepared in distilled water (DW) in order to study its killing effect, and in Brain Heart Infusion (BHI) broth for the suppressive effect. Pathogen cocktail was inoculated (4 log CFU/ml) in both DW and BHI at each concentration level and incubated at 7oC and 21oC. Pathogen counts were made for the DW at 0, 1, 5, 7, and 24 hr, and for the BHI on days 0, 1, 3, and 5. Results from the DW experiments showed that while no reduction of pathogens was observed in pure DW (0% treatment) at 7oC or 21oC, killing effects on four pathogens started at 1 hr in 10% and at 7 hr in 2.5, 5.0, and 7.5% concentrate. At 24 hr, no pathogens were recovered from the 10 % treatments. Both S. Typhimurium and L. monocytogenes, were reduced to non-detectable level at 5 hrs in 10% cranberry concentrate at both 7oC and 21oC. BHI data indicated that the growth of all pathogens tested was reduced compared to the negative control at both temperatures. No colonies were observed for S. Typhimurium at 10 % after 5 days at both 7oC and 21oC. The cranberry concentrate has significant killing and suppression effects on the foodborn pathogens tested. Based on various heath benefits and antimicrobial effects, cranberries may be considered for potential food applications, such as food preservatives.
Session 89D, Food Microbiology: Antimicrobial effects on foodborne microorganisms
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |