Effect of organic acids and plant extracts on Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella Typhimurium in broth culture model and chicken meat systems.

Foodborne illness due to consumption of products contaminated with Salmonella Typhimurium (S.T.), Listeria monocytogenes (L.m.), and Escherichia coli O157:H7 (E.c.) results in many deaths and significant economic losses each year. In this study, acetic (AA), citric acid (CA), lactic acid (LA), malic acid (MA), and tartaric acid (TA) and grape seed (GS), green tea (GT), bitter melon seed (BMS), rasum, and fenugreek (FG) extracts were investigated as inhibitors against S.T., L.m., and E.c. in both broth-culture and meat systems. Brain Heart Infusion solutions containing 18.7, 37.5, and 75.0 mM organic acids and 5, 10, 20, and 40 mg/mL extracts were challenged with approximately log 6 CFU/mL S.T., L.m., and E.c. A pH-adjusted control was included to determine pH effect on exhibited antibacterial activity. For the meat system, 1 to 2 g chicken breast pieces were vacuum-infused with CA/MA/TA acid at 75 and 150 mM and GS and GT at 3000, 6000, and 9000 ppm in a partial factorial arrangement. GT and GS showed considerable activity in broth-culture. All organic acids were effective in broth-culture at 75 mM after 24 h (P < 0.05). CA and TA were effective at 37.5 mM. CA/MA/TA at 150.0 mM were the most effective in the meat system, reducing E.c., L.m. and S.T. by >5, >2, and 4-6 log CFU/g, respectively, although all organic acids showed some antibacterial activity at 75.0 and 150.0 mM. These findings demonstrate the effectiveness of organic acids and plant extracts in the control of S.T., L.m., and E.c. O157:H7.