Meals on Wheels has recalled its frozen meals in SA after a routine test revealed a roast lamb and vegetable meal was contaminated with the listeria bacteria.

All frozen Meals on Wheels meals have been recalled in South Australia after the listeria bacteria was found in a sample.

A routine test revealed a roast lamb and vegetable meal prepared at the Kent Town kitchen was contaminated, but there have not yet been any reports of illness connected to the meals.

Meals on Wheels chief executive Julie Bonnici said the meals in question pose minimal risk when they are correctly heated and served.

"Some of the affected meals were supplied as frozen meals, which have safe thawing and heating instruction on the meal lid and, if heated correctly, also pose low risk," she said.

"However, Meals on Wheels is taking the step of recalling all affected frozen meals currently with customers in South Australia that may pose a risk if not heated correctly after thawing."

The source of the contamination is now under investigation, as the organisation works to warn clients and recall up to 6000 meals.

A listeria infection can cause fever, headache, vomiting and decreased alertness.

Meanwhile, a major egg recall is under way after five people in Victoria contracted the salmonella virus.

Eggs produced by Victoria's Bridgewater Poultry have been recalled in four states, but only the Loddon Valley 600 gram variety was sold in South Australian supermarkets.