The first part of EFSA’s analysis of an EU-wide baseline survey on Listeria monocytogenes published today provides valuable insights into the presence of this bacteria in certain ready-to-eat foods (fish, cold meats and soft cheeses). The proportion of food samples exceeding the legal food safety limit was low. However, given the popularity of these foods and the severe implications that Listeria infections (listeriosis) can have on human health, overall vigilance regarding the possible presence of the bacteria in food is warranted. To prevent listeriosis, EU legislation lays down specific rules for food business operators including the need to follow good manufacturing practices, appropriate food hygiene programmes, and effective temperature control throughout the food chain. Experts highlighted the importance of these measures as well as proper storage of these foods in the home, keeping refrigerator temperatures low.
Although listeriosis is rare, the disease is often severe with high hospitalisation and mortality rates. In the EU about 1,470 human cases were reported in 2011, with a mortality rate of 12.7%. Listeriosis is usually contracted by eating foods that contain the Listeria monocytogenes bacteria such as fish, cold meats and soft cheeses. Ready-to-eat foods are often the source of listeria infections as their long shelf life is conducive to bacterial growth and these foods are usually consumed without any additional cooking.
Health effects associated with listeriosis range from mild flu-like symptoms, such as nausea, vomiting and diarrhea to more serious infections such as meningitis and other potentially life-threatening complications. People who are more susceptible to Listeria infections are the elderly, pregnant women, newborn infants and people with weak immune systems.
EFSA’s report shows that Listeria monocytogenes was found in 10.3% of fish, 2.1% of meat and 0.5% of cheese samples collected from supermarkets and shops. However, the EU food safety limit (100 bacteria per gram) was exceeded only in 1.7% of fish, 0.4% of meat and 0.06% of cheese samples.
EFSA’s experts recommend adherence to good hygienic practices throughout the food production, distribution and storage chain. In the home consumers are advised to keep the temperature of their refrigerators low in order to limit potential growth of Listeria should it be present in ready-to-eat foods.
In the second part of the study, expected to be finalised next year, EFSA will look at the risk factors for the presence of Listeria monocytogenes in the food categories concerned and the factors favouring its growth in fish.
- Ready-to-eat foods are foods intended by the producer for direct consumption without the need for cooking or other processing.
- National food safety agencies in the EU provide practical advice to consumers regarding food and kitchen hygiene and generally recommend that refrigerators are set between 0°C and 5°C, in line with advice provided by the World Health Organisation (see Five Keys for Safer Food).
 The survey on the prevalence of Listeria in certain ready-to-eat foods was carried out in 26 EU Member States and Norway from January 2010 to January 2012. It looked at the presence of Listeria monocytogenes bacteria in ready-to-eat fish products (packaged, hot-smoked or cold-smoked and cured fish), packaged heat-treated meat products (such as cooked sliced ham and cooked chicken fillet, and pâtés) and soft or semi-soft cheeses. Overall, EFSA examined results from 13,088 samples taken from supermarkets and shops across the EU. The survey was designed to assess prevalence and levels of listeria in ready-to-eat foods at EU level but results are not necessarily representative of the situation in each of the individual countries.
 This figure is taken from the European Union Summary Report on Trends and Sources of Zoonoses, Zoonotic Agents and Food-borne Outbreaks in 2011. There was no statistically significant increasing or decreasing trend in confirmed human cases of listeriosis observed at the EU level from 2008 to 2011. According to the EU Summary Reports available when the study was designed, an increasing trend in the notification rate of listeriosis cases was observed between 2002 and 2006.