29F-16 |
Antioxidant and antimicrobial activities of selected natural extracts |
J. AHN1, I. U. Gruen2, and A. Mustapha1. (1) Department of Food Science, University of Missouri, 256 Eckles Hall-Stringer Wing, Columbia, MO 65211, (2) Dept. of Food Science, Univ. of Missouri, Columbia, 256 Eckles Hall - Stringer Wing, Columbia, MO 65211
Lipid oxidation and microbial contamination have always been a great concern to the meat industry. The growing concern for meat quality and safety has led to the use of natural extracts. Natural extracts containing polyphenolic compounds are known to retard lipid oxidation and inhibit microbial growth. The objective of this
research was to investigate the antioxidant effects and antimicrobial
activities of selected natural extracts in a raw meat system. Natural extracts of grape seed (ActiVin™), pine bark (Pycnogenol®), and rosemary were used. Lipid oxidation was estimated by thiobarbituric acid reactive substance (TBARS) analysis. Surface color of raw beef was expressed by the L*, a*, and b* coordinates. Listeria monocytogenes, Salmonella Typhimurium, and Escherichia coli O157:H7 were cultivated in trypticase soy broth supplemented with 0.1% yeast extract prior to use. Endpoint and descriptive screening methods with slight modifications were used to test the antimicrobial activities of selected natural extracts. The experiment was designed as a randomized complete block design, and all analyses were performed with duplicate for three replicates. ActiVin™ most effectively retarded lipid oxidation in raw beef during refrigerated storage, followed by Pycnogenol® and rosemary. ActiVin™ (1%) and rosemary (1%) showed the highest a* and b* values, respectively. All three pathogens were inhibited by ActiVin™ and Pycnogenol® for 12 h in an agar dilution test. The maximum reduction rate was 0.44 CFU/h on L. monocytogenes treated with 1% Pycnogenol®. ActiVinTM and Pycnogenol® showed bactericidal effects against L. monocytogenes. Antimicrobial activity depended on the initial numbers of pathogens and concentration of natural extracts. L. monocytogenes, S. Typhimurium, and E. coli O157:H7 were reduced by 1.24, 1.33, and 1.08 CFU/g, respectively, during the refrigerated storage of raw beef with 1% Pycnogenol®. These results suggest
that the use of natural extracts may be a useful approach to control
lipid oxidation and microbial contamination and hence provide an improvement in
meat quality and safety.
Session 29F, Food Microbiology: Control of foodborne microorganisms by antimicrobials
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