Listeria monocytogenes in Retail Delicatessens: An Interagency Risk Assessment—Risk Mitigations

Abstract

Cross-contamination, improper holding temperatures, and insufficient sanitary practices are known retail practices that may lead to product contamination and growth of Listeria monocytogenes. However, the relative importance of control options to mitigate the risk of invasive listeriosis from ready-to-eat (RTE) products sliced or prepared at retail is not well understood. This study illustrates the utility of a quantitative risk assessment model described in a first article of this series (Pouillot, R., D. Gallagher, J. Tang, K. Hoelzer, J. Kause, and S. B. Dennis, J. Food Prot. 78:134-145, 2015) to evaluate the public health impact associated with changes in retail deli practices and interventions. Twenty-two mitigation scenarios were modeled and evaluated under six different baseline conditions. These scenarios were related to sanitation, worker behavior, use of growth inhibitors, cross-contamination, storage temperature control, and reduction of the level of L. monocytogenes on incoming RTE food products. The mean risk per serving of RTE products obtained under these scenarios was then compared with the risk estimated in the baseline condition. Some risk mitigations had a consistent impact on the predicted listeriosis risk in all baseline conditions (e.g. presence or absence of growth inhibitor), whereas others were greatly dependent on the initial baseline conditions or practices in the deli (e.g. preslicing of products). Overall, the control of the bacterial growth and the control of contamination at its source were major factors of listeriosis risk in these settings. Although control of cross-contamination and continued sanitation were also important, the decrease in the predicted risk was not amenable to a simple solution. Findings from these predictive scenario analyses are intended to encourage improvements to retail food safety practices and mitigation strategies to control L. monocytogenes in RTE foods more effectively and to demonstrate the utility of quantitative risk assessment models to inform risk management decisions.

Genetic diversity and profiles of genes associated with virulence and stress resistance among isolates from the 2010-2013 interagency Listeria monocytogenes market basket survey

“…Following the 2003 FDA-FSIS risk assessment and several other product-specific risk assessments to evaluate the impact of interventions [5,6,36], FDA and FSIS issued regulations and guidance on risk-based Listeria control [1,[37][38][39][40][41]. The food industry, working with academia, also developed guidance for risk-based Listeria control and made changes to industry practices [42][43][44][45][46].…”

Closing gaps for performing a risk assessment on Listeria monocytogenes in ready‐to‐eat (RTE) foods: activity 3, the comparison of isolates from different compartments along the food chain, and from humans using whole genome sequencing (WGS) analysis

“…The first is linked to cross-contamination at retail level. It has been recently shown that cross-contamination at retail is of major importance for L. monocytogenes (Pouillot et al, 2015;Gallagher et al, 2016). Yet cross-contamination probably concerns products of the same food category, e.g.…”

Food-Borne Disease Prevention and Risk Assessment

“…Extensive testing and observations of worker behavior showed that these deli meats tended not to contain added inhibitors; resident L. monocytogenes were present in niches in equipment and spread through cross-contamination from food contact and non-food contact surfaces; and there was lack of adequate sanitation; inadequate temperature control; and inappropriate glove/hand issues. This information was used to create a "virtual deli" model and to generate six baseline situations and 22 scenarios by the U.S. Department of Health and Human Services; Center for Food Safety and Applied Nutrition, Food and Drug Administration and the U.S. Department of Agriculture Food Safety and Inspection Service [24][25][26]. Overall, the virtual deli model indicated that the greatest risk was from contamination present in an incoming chub of a product that permitted growth of Listeria.…”