Abstract: Listeria monocytogenes is a foodborne human pathogen responsible for severe listeriosis and poses a great threat to human health. Hence, controlling the growth of L. monocytogenes plays an important role in the prevention of food contamination. Listeria innocua is often studied experimentally as a substitute strain for L. monocytogenes. In order to better maintain the sensory properties and nutrients of foods and extend their shelf life, this study explored the antimicrobial effect and possible mechanism of high pressure processing (HPP) combined with lauroyl arginate ethyl ester hydrochloride (LAE) on L. innocua. The feasibility of applying the combined treatment as a preservative was also investigated in ham. The results showed that 12 mg/L LAE treatment for 60 minutes had a potent antimicrobial effect on L. innocua, achieving a bacterial reduction of 3.12 (lg (CFU/mL)). Under the combined action of HPP and LAE, the surface morphology of bacterial cells became more wrinkled and sunken, and intracellular contents leaked out, suggesting a severe change in cell membrane permeability. The combined treatment of HPP at 350 MPa for 5 min with 12 mg/L LAE reduced L. innocua count by 4.87 (lg (CFU/mL)), which was 3.25 and 3.54 (lg (CFU/mL)) higher than that achieved using HPP and LAE treatments alone, respectively, suggesting a synergistic antimicrobial effect. Such synergistic antimicrobial effect was also observed on ham inoculated with L. innocua. This study could provide a theoretical reference for controlling the contamination of foodborne pathogens in ready-to-eat meat products.

Key words: high pressure processing; lauroyl arginate ethyl ester hydrochloride; combined antimicrobial effect; Listeria innocua; membrane permeability