Food Safety Focus (17th Issue, December 2007) – Food Incident Highlight

Listeria monocytogenes and Mussels

The Centre for Food Safety (CFS) appealed to retailers on 25 November to stop selling certain lots of frozen mussel meat from New Zealand (NZ) due to the suspected contamination with Listeria monocytogenes . The alert was made after the CFS was informed by the NZ authority of a product recall as the bacterium was detected in samples of frozen mussel meat processed in NZ and the products suspected to be contaminated had been exported to Hong Kong .

Although listeriosis is uncommon in Hong Kong and the symptoms of infection are rare in healthy individuals, the elderly, the newborn, pregnant women and people with weakened immunity are particularly at risk. The bacteria exist naturally in soil and water and consequently exist in many raw foods. Cooking can kill the bacteria. However, they tend to grow in refrigerated food that is contaminated and therefore one must be careful when handling cooked food to prevent re-contamination.

People of the susceptible groups should avoid consuming high risk food such as chilled ready-to-eat foods and refrigerated foods. They include unpasteurised dairy products, soft cheeses, cold cuts, pate, prepared salads, smoked and raw seafood.

Illustration: A sample of the frozen mussels that are affected by the recall