Cross-contamination of ready-to-eat meat products during slicing step in the retail market: risk of Listeria monocytogenes

Abstract

Cross-contamination of ready-to-eat meat products during slicing at retail level: risks related to Listeria monocytogenes. Cross-contamination of foods with undesirable microorganisms, caused by direct or indirect contact with contaminated surfaces and handlers, can bring serious consequences for consumers, especially in relation to Listeria monocytogenes, which causes foodborne illness with high severity and mortality rates (20 to 30%), especially in immunocompromised individuals. Foods with higher risk in relation to L. monocytogenes are those ready-to-eat, kept under refrigeration and with long shelf life, which favor the growth of this pathogen. The thermal processing of foods is usually sufficient to eliminate this organism, but cross-contamination after thermal processing can result in increased risk to health. Considering the impact on public health of ready-to-eat products that become contaminated with L. monocytogenes in retail, this project proposes to evaluate the transfer of this pathogen (cross contamination) during slicing of roast beef, a product of wide acceptance by consumers in Sao Paulo. A manual slicer, like those used at retail for slicing cold cuts (cheeses, meat products, etc.) will be experimentally infected with L. monocytogenes by slicing a roast beef sample contaminated with the pathogen, verifying how this contamination is transferred to products that are sliced afterwards. The experimental contamination will be in two levels: 108 CFU/g (high level) and 104 CFU/g (low level), and the monitoring the populations of L. monocytogenes in the slices will be done by culture-dependent (ISO 11290-2:1998) and culture-independent (qPCR) techniques. This work is inserted in a collaborative project with researchers from the Danish Technical University in Copenhagen, Denmark (FAPESP Project-DCSR 2012/50535-5 Meat safety: an innovative modellling approach to evaluate microbial pathogen transfer and cross-contamination from farm to fork - meat-cross-con). It is also inserted in the RIDC-FoRC (FAPESP Project 2013/07914-8 Food research center), tuned with the objectives of Pillar 3 (food safety and quality). (AU)