Combined application of phenolic acids and essential oil components against Salmonella Enteritidis and Listeria monocytogenes in vitro and in ready-to-eat cooked ham

Abstract

Essential oil components (EOCs) show great potential for substitution of classic synthetic preservatives in the food industry, but their intense flavor at high concentrations hinders the commercial use. When combined with phenolic acids (PAs), however, the amount of EOC needed to inhibit microbial growth can be significantly reduced. In this study, we aimed to assess the effects of several combinations of EOCs and PAs on the growth of foodborne pathogens and, thereafter, evaluate the best combination in sliced ham, a highly susceptible product to bacterial contamination in retail shops. Most combinations showed additive effects in vitro against a 4-strain cocktail of Salmonella Enteritidis and a Listeria monocytogenes strain culture. The most effective combination, cinnamaldehyde (CINN) and 2-hydroxycinnamic acid (HCA), was evaluated in ready-to-eat (RTE) cooked ham. A package system based in filter papers was designed for continuous delivery of cinnamaldehyde (CINN) and 2-hydroxycinnamic acid (HCA) into the meat matrix. The treatment showed no significative effects in pathogen populations, instrumental color or pH throughout shelf life. Storage time exerted statistical influence in pH, but values remained as expected for ham. L. monocytogenes population varied through storage time, probably due to the psychrotrophic nature of this species.