Reduction of Listeria monocytogenes in Deli Meat using Enterococcus faecium J19 and Lactobacillus sakei L15

Abstract

Listeria monocytogenes is a major food safety concern in ready-to-eat (RTE) meats, particularly deli hams, due to its psychrotrophic growth and persistence in food-processing environments. Control measures such as treatments or chemical agents already used by the industry following established regulations, such as sodium diacetate, show efficiency, but do not align with the increasing consumer demand for clean-label products. In this study, the antimicrobial potential of two lactic acid bacteria (LAB) strains molecularly charaterized by the International Center for Food Industry Excellence (ICFIE), Enterococcus faecium J19 (GenBank Code: PHUR00000000) and Lactobacillus sakei L15 (GenBank Code: SCIF00000000), was evaluated against L. monocytogenes on deli ham slices stored under retail-simulating conditions (4 °C). Treatments were applied by surface spraying, and microbial counts were monitored over 21 days. Results demonstrated that both have significant antilisterial effects, with J19 showing the greatest inhibitory activity compared to sodium diacetate (blank) and control treatments. The activity was attributed to bacteriocin production during the stationary phase of the bacterial growth curve and to the ability of LAB to survive under refrigeration. Practical considerations include the potential for alternative application methods, such as immersion or incorporation into edible films, which may enhance efficacy. Limitations include the evaluation of a single inoculation level, a relatively short storage period, and the absence of combined treatments, which previous studies suggest may produce either antagonistic or synergistic effects. Results support the use of LAB as clean-label protective cultures to enhace microbial safety and extend the shelf life of RTE meats.