UK – A recent study conducted by scientists from the Quadram Institute and the UK Health Security Agency sheds light on the persistence of Listeria monocytogenes bacteria in ready-to-eat (RTE) food production environments, despite adherence to sanitation best practices.

This research, led by Dr. María Díaz, M.Sc., Ph.D., aims to better understand the factors contributing to L. monocytogenes persistence following a fatal foodborne illness outbreak in 2019 linked to RTE hospital food.

The study focused on an RTE food factory with a history of recurrent L. monocytogenes detection in certain non-food-contact areas.

Over a ten-week period, researchers sampled the factory’s preparation and production areas before and after cleaning.

Genetic sequencing of cultured samples revealed stable populations of bacteria coexisting with L. monocytogenes, indicating adaptation to the factory environment despite implemented food safety controls.     

Dr. Díaz highlights the need for new strategies to alter entire bacterial populations to eliminate L. monocytogenes from facilities fully.

While cleaning remains crucial for reducing bacterial load and cross-contamination, stable bacterial populations persist regardless of sanitation efforts. Additionally, significant differences in bacterial populations between areas with different temperatures suggest highly adapted environments within the facility.

Advancing understanding of microbial communities

The findings contribute to a better understanding of microbial communities and L. monocytogenes survival in RTE facilities, informing the validation of cleaning methods and the development of new strategies for pathogen inactivation.

Dr. Díaz will present her data at the 2024 Microbiology Society Annual Conference, providing insights into microbial dynamics and potential interventions to enhance food safety practices.

Continued research will explore methods to disrupt stable bacterial populations and improve cleaning efficacy in RTE facilities.

Advancing our understanding of microbial behavior and environmental adaptation will help scientists enhance food safety protocols and mitigate the risk of L. monocytogenes contamination in RTE products.

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