The Use of Selected Phytochemicals to Control Listeria monocytogenes; Practical Applications in Food Safety

Abstract

Listeria monocytogenes is an important foodborne pathogen found in minimally processed foods, such as dairy products. To improve detection methods, phytochemicals were screened against L. monocytogenes and L. innocua. Efflux pump inhibitors promoted the growth for L. monocytogenes strain (FSL-J1-031) over L. innocua strain (2007-663). When tested against multiple strains of Listeria there was no clear differential effect observed. Aiming to control L. monocytogenes, biofilm growth kinetics of 2% Milk Fat pasteurized milk at 4°C was investigated, with a mature biofilm-forming at 74 h. Preformed biofilms were exposed to 20 phytochemicals in vitro with carvacrol, thymol, eugenol, coriander essential oil, and tea tree essential oils removing between 89% and 97% of the biomass. When tested in dispensing pumps, phytochemicals reduced biomass by 17% (thymol) and 32% (thymol) with mechanical force. Further research is needed to identify natural antimicrobial agents and techniques that are more effective for controlling L. monocytogenes.