As a foodborne pathogen, Listeria monocytogenes raises concern to food producers worldwide. Along with its ability to succeed in harsh environments, it can co-live with other bacteria in polymicrobial biofilms that cause cross-contaminations events. Paradoxically, little is known about the transfer of L. monocytogenes from polymicrobial biofilms to food products. The present work aims to model transfer events from two L. monocytogenes-positive contamination foci – L96 and L168 – found on surfaces from the seafood and meat industry, respectively. Polymicrobial biofilms were grown in low-nutrient medium under static conditions for 72 h. To simulate successive contaminations events, up to 25 contacts (with 20 replicates each) were made between each biofilm and smoked salmon slices. Bacterial transfer data were expressed as transfer rates. Kruskal-Wallis and Dunn’s test grouped contacts in four groups significantly different (p = 0.05). The density distributions of these groups were displayed and fitted to Weibull, Normal and Gamma models. The outcomes give insight about the transfer ability of mixed biofilms containing L. monocytogenes, which can help quantify the risk of contamination in the food industry

Symposium on Listeria monocytogenes in Foods: recent advances and outstanding questions, 24th-25th May 2023, Dublin

No