Antibacterial Activity of Commercially Available Plant Extracts on Selected Campylobacter jejuni Strains.

摘要

Campylobacter jejuni is recognized as a leading cause of foodborne illness worldwide with approximately 850,000 cases per year in the United Sates. A total of 18 species of Campylobacter have been identified worldwide to date. Foodborne transmission of C. jejuni is mainly through the consumption of unpasteurized milk, contaminated poultry meat and water. C. jejuni can survive in very diverse environments under stressful conditions in human and animals which is different from the specific conditions and media required in laboratory experiments. There has been increased research in recent years to identify naturally occurring antibacterial agents to control and eliminate C. jejuni on poultry. This study involves the evaluation of commercially available plant extracts of oregano, green tea and hawthorn to reduce /eliminate C. jejuni on poultry. Four isolates of C. jejuni, one human and three poultry isolates were used in this study. Research was done in broth culture to determine the effects of these extracts at different concentrations on the 4 isolates using cell counts at regular intervals of 0, 1, 2, 4 and 24 hours post-treatment. Results indicated that oregano and green tea were the most antibacterial and killed all the bacteria in broth culture in 24 hours at all concentrations tested. No significant differences were observed on the action of each of these plant extracts on the different isolates. Hawthorn was not successful in killing any of the strains of C. jejuni in 24 hours and no significant difference in cell counts post-treatment was observed compared to the control. The effects of these plant extracts then were tested as marinades on chicken breast fillets. The results showed that higher concentrations were required in the meat model study as compared to broth studies to completely kill all the bacteria. In the marinade studies, oregano was found to be the most effective, killing all 81176 and PRCC isolates in 2 hours and all the POCC and RECC C. jejuni isolates in 6 hours. The extracts of green tea and hawthorn tested were unsuccessful in killing the C. jejuni isolates within 24 hours at all tested concentrations. The results of this study indicate the potential of using oregano extracts as antimicrobial against C. jejuni on poultry.