89D-1 |
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Y.-T. LIN, Y.-I. Kwon, R. G. Labbe, and K. Shetty. Dept. of Food Science, Univ. of Massachusetts, Amherst, Chenoweth Lab., Box 31410, Amherst, MA 01003-1410 Staphylococcus aureus is a gram-positive bacterium usually appearing in pairs, or grape-like clusters. Some strains are able to producing a heat-stable protein toxin that causes foodborne illness in humans. Staphylococcal food poisoning is caused by ingesting staphylococcal toxin in contaminated food. The most common symptoms of staphylococcal food poisoning are nausea, vomiting and abdominal cramping and recovery takes 2-3 days. Many naturally occurring phenolic compounds found in dietary and medicinal plants such as herbs and fruit extracts have been shown to possess antimicrobial activities against common types of food poisoning agents, such as Listeria monocytogenes and Staphylococcus aureus. To screen phenolic antimicrobial profiles we have developed a novel two layer screening method. In this method, a bottom layer of plant tissue culture medium allows elicitation of phenolics from clonal lines that can migrate to the top bacterial lawn layer spread on a bacterial growth medium. The presence of antimicrobial diffusion is indicated by an inhibition zone in the bacterial medium around the inserted clonal line. This approach allows the isolation of clonal lines that contain high antimicrobials specific to S. aureus. Plant clonal tissue cultures from various single seed origins were developed in this study. Specific clonal lines investigated were oregano, rosemary, basil, tea tree, St. John′s wort and spearmint. The results indicated that oregano and rosemary had the highest inhibitory activity against S. aureus based on the extended zone of inhibition in the 2-layered plate assay. This study shows the potential of using specific bacteria as a screening target to isolate high antimicrobial producing lines and utilizing these high antimicrobial producing lines to target specific food-borne pathogens. This also offers a novel approach to couple antioxidant-enriched benefits of plant with antimicrobial effectiveness and which can be considered as ″generally regarded as safe″ (GRAS).
Session 89D, Food Microbiology: Antimicrobial effects on foodborne microorganisms
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |