Food Safety Focus (195th Issue, October 2022) – Article 4

Risk of Listeria Infections in High-risk Population

Listeria monocytogenes (LM) has been found in both locally manufactured and imported chilled food from time to time. LM can multiply in foods that are stored chilled at 4°C or below for extended period. This is an issue in ready-to-eat foods like cold cuts, smoked or raw seafood, soft cheeses, prepared and stored salads, unpasteurised milk and its products, as they are usually not cooked or reheated before consumption. Susceptible populations, including the elderly and immunocompromised, can suffer serious health consequences such as septicaemia, meningitis and encephalitis when infected. Infected pregnant women can transmit LM to their foetuses, leading to miscarriage, stillbirth, premature birth or serious illnesses in newborn babies.

To reduce the risk of LM infection, susceptible populations should (1) consume freshly prepared hot food where possible; (2) reheat chilled food until it is hot all the way through (core temperature reaches at least 75°C); and (3) avoid high-risk foods or cook them thoroughly before consumption, even if they are presented as part of a dish.