29F-8 |
Antimicrobial effect of fruit extracts on foodborne pathogens in liquid medium |
S. KIM, Animal Sciences and Industry, Kansas State University, Call Hall 202, Manhattan, KS 66506 and D. Y. C. Fung. Numerous antimicrobial compounds are naturally present in plant sources. Extracts from fruits have been reported to possess antimicrobial properties. Seven kinds of fruit extracts were determined on antimicrobial effect against four foodborne pathogens, Escherichia coli O157:H7 ATCC 35150, Salmonella enteritidis USDA-FSCS 15060, Listeria monocytogenes ATCC 19115, and Staphylococcus aureus ATCC 25178, in Nutrient broth (NB) medium. Each fruit extract in powder form (Blueberry, Cranberry, Elderberry, Concord Grape, Red Raspberry, Strawberry, Red Sour Cherry, OceanSpray Co., Lakeville, MA) was dissolved in 10 ml NB tubes to make fruit solution of 5% (w/v). The cocktail of 24 h-culture of the four pathogens was inoculated into fruit solutions at 5 log cfu/ml. After incubation at 35°C for 0, 3, 6, 12, and 24 h, samples were serially 10-fold diluted. The proper diluent was spread-plated on PCA and pathogen-specific agar in duplicate. After incubation at 35°C for 24-36 h, viable cell counts were obtained. The experiment was replicated three times. For total pathogenic bacteria on PCA, Cranberry and Strawberry showed >5 log reduction and Blueberry, 4.5 log reduction, compared to the control at 24 h. Strawberry showed the highest antimicrobial activity against E. coli O157:H7 on MSA by 6.7 log reduction; Cranberry, 5 log reduction; and Blueberry, 4.3 log reduction at 24 h. Both Cranberry and Strawberry showed the highest microbial reduction against S. enteritidis on XLD by ca. 6.4 log reduction and Blueberry, 4.6 log reduction at 24 h. In both L. monocytogenes on MOX and S. aureus on BP, Blueberry, Elderberry, Concord Grape, Red Raspberry, Red Sour Cherry showed 3-4 log reduction, while Cranberry and Strawberry did ca. 5 log reduction at 24 h. In conclusion, Cranberry and Strawberry extracts at 5% showed the highest activity against all test cultures in BHI medium.
Session 29F, Food Microbiology: Control of foodborne microorganisms by antimicrobials
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