Antibacterial Activity of Commercially Available Plant Extracts on Relevant Campylobacter Jejuni Strains Isolated from Both Human and Poultry

Food contaminated with bacterial pathogens is still a problem worldwide. Campylobacter jejuni causes over 99% of the foodborne infections associated with Campylobacter in the United States. This study involves the evaluation of commercially available plant extracts of oregano, green tea, hawthorn, and curcumin against four isolates of C. jejuni. In this study, four different strains of C. jejuni were used: one human strain (81176) and three poultry strains isolated from different stages of poultry processing including a pre-chilled chicken carcass (PRCC), a post-chilled chicken carcass (POCC) and a retail chicken carcass (RECC). Initial studies were first carried out in broth cultures to determine the general effectiveness of the extracts. The study then was carried out on chicken breast meat to determine the effect of the plant extracts in marinades. Cell counts were determined at intervals of 0, 2, 6 and 24 hours and bacterial viability was determined using different concentrations of the above extracts. Both oregano and green tea extracts were found to be antibacterial even at low concentrations in broth cultures and killed all bacteria in 24 hours. But as marinades on chicken breast meat, the extracts were found to be effective only at higher concentrations. No significant differences were found in the antibacterial effects of the extracts on different C. jejuni strains. These results demonstrate that commercially available plant extracts such as oregano and green tea have the potential to reduce and/or eliminate C. jejuni in chicken meat. Combinations of plant extracts have to be explored to resolve the problem of the high concentration required to inhibit C. jejuni strains in meat.