Listeria monocytogenes (Lm) is an environmental zoonotic pathogen with a high level of human mortality. It is found in soil and water and animals can carry Listeria monocytogenes without appearing ill.
Lm has been found in a variety of raw foods, such as uncooked meats and vegetables, as well as in processed foods that become contaminated after processing. Lm is killed by heating; however contamination may occur after cooking but before packaging. Lm can easily become established in the factory environment since chilling and general good levels of hygiene reduce the number of competitors, and wet conditions can encourage its survival and growth.
Legal limits have been set at EU level for Listeria monocytogenes in food and areas used for the manufacture of ready to eat (RTE) foods are required by EU law to be swabbed for the organism, although swabbing for Listeria spp as an indication of the presence of Lm is confirmed by FSA as being acceptable.
Specific Lm strains appear to persist in the environments of food production areas over time. Lm control strategies therefore need to address the control and eradication of persistent strains to reduce the risk of finished product contamination from environmental sources. However, Lm is likely to be consistently reintroduced into processing plants from a variety of sources, including personnel, equipment, and raw materials and control strategies must take account of this.
This guidance aims to provide pointers for the practical management of Lm, both in its prevention of entry to a factory and in dealing with its establishment, thereby minimising risk to the consumer and to your business. The guidance is not exhaustive but is designed to assist in identifying key issues to be addressed.