The Centre for Food Safety warns consumers not to eat a batch of Midwest Pride potato salad, suspected to be contaminated with Listeria monocytogenes. Retailers have been told to stop selling the product.

American authorities say the affected pre-packaged (1lb) product containers carried lot number 7057018A, with an April 2, 2007, expiry date. The centre is seeking more information and is monitoring the situation.

Listeria symptoms include fever, headache, vomiting and diarrhoea, but its effect on pregnant women, babies, the elderly and people with lowered immunity can be severe, and include miscarriage and meningitis.