Ready-to-Eat (RTE) Food Contaminated with Listeria monocytogenes

Listeria monocytogenes and Health

Q1. What is Listeria monocytogenes?
Listeria monocytogenes (LM) is a bacterium commonly found in soil and water.  LM can be easily destroyed by cooking but can survive and multiply even at refrigerator temperature (0oC - 4oC).  Eating food contaminated by LM may result in listeriosis.
What types of food are at higher risk?
Refrigerated ready-to-eat food with a long shelf life (greater than five days) such as smoked salmon, smoked ham, deli meats, etc. are high risk food items with respect to listerosis.
Who are at risk populations?
Most healthy individuals do not develop symptoms or only have mild symptoms like fever, muscle pain, headache, nausea, vomiting or diarrhoea when infected.  However, severe complications such as septicaemia, meningitis or even death may occur in newborns, elderly and those with a weaker immune system.  Although infected pregnant women may just experience mild symptoms generally, the infection of Listeria monocytogenes may cause miscarriage, infant death, preterm birth, or severe infection in the newborns.

Advice to the Trade

Q4. How could the trade ensure the food safety of their food products?
The trade should maintain good hygiene and food handling practices in food manufacturing plants, food premises and retail establishments.  Moreover, they should avoid post-cooking contamination of ready-to-eat food particularly those with long shelf life.