29F-24 |
Inhibition of Listeria monocytogenes in fish and meat systems using GRAS plant extracts |
Y. T. LIN, R. G. Labbe, and K. Shetty. Dept. of Food Science, Univ. of Massachusetts, Amherst, Chenoweth Lab., Box 31410, Amherst, MA 01003-1410 Listeria species have been isolated from soil, decaying vegetable matter, silage, sewage, water, animal feed, fresh and processed meats, raw milk, cheese, slaughterhouse waste, and asymptomatic human and animal carriers. Due to their widespread occurrence, Listeria species have many opportunities to enter food production and processing environments. With their prevalence in food products any emerging outbreaks have received worldwide attention. Several food additives are used to extend food shelf life and delay or inhibit the growth of pathogenic microorganisms. Extracts of plants, particularly herbs and spices are rich in essential oil and secondary metabolites and possess antimicrobial activity. Some of these plant extracts are used in the aroma and flavor industry and classified as GRAS. We have developed a GRAS oregano and cranberry water extract for inhibiting Listeria monocytogenes. This provides the potential to develop a natural and consistently effective food-grade antimicrobial of plant origin against food-borne pathogens. Five concentrations of phenolics were optimized from oregano and cranberry extracts (0 mg/ml, 0.05 mg/ml, 0.1 mg/ml, 0.15 mg/ml, 0.2 mg/ml on phenolic basis) and evaluated for antimicrobial activity in market meat products (chicken, beef, seafood products). The growth of Listeria monocytogenes was effectively inhibited when phenolic content of mixed oregano and cranberry extracts reached 0.1mg phenolic/ml. The efficacy was further enhanced by using lactic acid, which is also considered GRAS. Use of these natural, food-grade antimicrobial ingredients will provide an additional protection beyond low temperature alone. Due to consumer interest in natural products and functional foods, a food-grade botanical ingredient with antioxidant properties would be a preferred choice for hurdle technology. These results show the antimicrobial potential of plant extracts to be antimicrobial, and when combined with lactic acid, can be used as a constituent of multiple-barrier food preservation systems.
Session 29F, Food Microbiology: Control of foodborne microorganisms by antimicrobials
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