39 ISSN 1120-1770 online, DOI 10.15586/ijfs.v33i1.1933 P U B L I C A T I O N S CODON P U B L I C A T I O N S CODON The antimicrobial activity of two phenolic acids against foodborne Escherichia coli and Listeria monocytogenes and their effectiveness in a meat system Oluwatosin Ademola Ijabadeniyi a *, Austin Govender a , Omotola Folake Olagunju a , Ajibola Bamikole Oyedeji b * a Department of Biotechnology and Food Technology, Durban University of Technology, Durban, South Africa; b Department of Biotechnology and Food Technology, Faculty of Science, University of Johannesburg, Gauteng, South Africa *Corresponding Authors: Oluwatosin Ademola Ijabadeniyi, Department of Biotechnology and Food Technology, Durban University of Technology, S9 Level 1, Steve Biko Campus, Durban 4000, South Africa. Email: oluwatosini@dut. ac.za; Ajibola Bamikole Oyedeji, Department of Biotechnology and Food Technology, Faculty of Science, University of Johannesburg Doornfontein Campus, P.O. Box: 17011, Gauteng 2028, South Africa. Email: jibanky2@gmail.com Received: 21 July 2020; Accepted after revision: 14 December 2020; Published: 1 February 2021. © 2021 Codon Publications OPEN ACCESS PAPER Abstract Ready-to-eat meats are susceptible to pathogenic contamination during their production, distribution, and sale. Tis study evaluated the antimicrobial efects of two phenolic acids (cafeic and ferulic acids) against foodborne pathogens in cold-cut meat at low-temperature conditions. Te individual and combined antibacterial activities of cafeic and ferulic acids against Escherichia coli O157:H7 ATCC 43888 and Listeria monocytogenes ATCC 7644 were determined by difusion 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 cafeic 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. Cafeic 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. Te combination of cafeic-ferulic acid at a concentration of 200 ppm was most efective against E. coli, demonstrating a synergistic efect over 72 h at 4°C in both broth media and meat. For meat samples, the combination of cafeic 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. Cafeic 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. Tese results indicate the ability of cafeic and ferulic acids, individually and in combination, to reduce pathogenic contamination and improve safety of cold-cut meats. Keywords: antibacterial activity; cafeic acid; ferulic acid; cold-cut meat; E. coli; L. monocytogenes Introduction Cold-cut meat products such as ham are one of the most commonly consumed ready-to-eat products. Tey are often in sliced forms and used as fllings for sandwiches and similar foods. Tey are manufactured from raw pork and/or beef and characterized by physical and biochem- ical changes that occur during curing (Marušić et al., 2014). In most modern cold-cut meats, nitrites (either sodium nitrite or potassium nitrite) are employed during curing to prevent bacterial growth and survival and enhance safety and storage stability. However, owing to the toxicity of nitrites, some country regulations spec- ify maximum allowable contents in the fnal product (Campion et al., 2017). Tis indulges public health con- cern because, under certain conditions, nitrites in meat can react with degradation products of amino acids, forming nitrosamines, which are known carcinogens Italian Journal of Food Science, 2021; 33 (1): 39–45