The antimicrobial activity of two phenolic acids against foodborne Escherichia coli and Listeria monocytogenes and their effectiveness in a meat system

Abstract

Ready-to-eat meats are susceptible to pathogenic contamination during their production, distribution, and sale. This study evaluated the antimicrobial effects of two phenolic acids (caffeic and ferulic acids) against foodborne pathogens in cold-cut meat at low-temperature conditions. The individual and combined antibacterial activities of caffeic and ferulic acids against Escherichia coli O157:H7 ATCC 43888 and Listeria monocytogenes ATCC 7644 were determined by diffusion disk assay in broth media and cold-cut meat. Broth media and meat samples already inoculated with E. coli and L. monocytogenes were treated with caffeic acid, ferulic acid, and their combination at the concentrations of 150 ppm and 200 ppm and stored at 4°C. Microbial growths were monitored at 0, 24, 48, and 72 h. Caffeic acid at 200 ppm exhibited a zone of inhibition of 12.33 mm on E. coli, and ferulic acid revealed a zone of inhibition of 11.00 mm on L. monocytogenes. The combination of caffeic ferulic acid at a concentration of 200 ppm was most effective against E. coli, demonstrating a synergistic effect over 72 h at 4°C in both broth media and meat. For meat samples, the combination of caffeic acid and ferulic acid exhibited a log reduction of 3.63 CFU/g at 150 ppm and 2.51 CFU/g at 200 ppm against E. coli O157:H7 at the end of cold storage. Caffeic acid alone exhibited an overall log reduction of 2.48 CFU/g at 150 ppm and 2.75 CFU/g at 200 ppm against L. mono-cytogenes. These results indicate the ability of caffeic and ferulic acids, individually and in combination, to reduce pathogenic contamination and improve safety of cold-cut meats.