Control of foodborne pathogens on ready-to-eat roast beef slurry by ε-polylysine

This study evaluates the antimicrobial effectiveness of ε-polylysine against Escherichia coli O157:H7, Salmonella typhimurium and Listeria monocytogenes in laboratory media and roast beef slurry. ε-Polylysine supplemented laboratory media and roast beef slurry were inoculated with three-strain cocktails of each pathogen and survival was periodically monitored using conventional spread plating. Inoculated laboratory media was stored at room temperature (22 °C) for 48 h, and inoculated roast beef slurry was stored at 4 °C for up to 7 days. Maximum log reductions in laboratory media/roast beef slurry were 6.01 ± 1.43/3.81 ± 0.37, > 7.82 ± 0.05/5.23 ± 0.08, and 4.58 ± 0.86/5.83 ± 0.48 for E. coli O157:H7, S. tyhimurium, and L. monocytogenes, respectively. Injured cells were produced as a result of exposure to polylysine. This study confirms the effectiveness of polylysine against pathogens in laboratory media, and demonstrates its potential as a novel antimicrobial agent in complex food matrix such as roast beef.