Routine tests on cans of tomatoes sold under the Asda, Princes, Safeway and Tesco brand names showed levels of tin, which can cause vomiting and diarrhoea, exceeded statutory safety limits
The Ministry of Agriculture, Fisheries and Food (Maff) said affected batches had been removed from supermarket shelves and urged customers who had recently bought tinned tomatoes to contact their retailer.
Concerns were heightened when the Co-op announced that it had recalled cans of its own-label spaghetti in tomato sauce that its own tests found to contain unacceptable levels of tin. It said that the product originated at the same factory in Italy as one of the affected brands of canned tomatoes. Jeff Rooker, the Food Safety minister, sought to reassure the public by saying the food industry had taken a responsible attitude. "We are putting the information in the public domain, in line with Maff's commitment to openness and transparency in every area," he said.
The supermarkets yesterday declined to name the canning factories that supplied the contaminated tomatoes.
Steel food cans are lined with a thin layer of tin because the metal does not corrode. A Maff spokesman said that in some batches the average level of tin found in the tomatoes was 279 milligrams per kilogram, with one tin registering 293 mg/kg. The statutory limit is 200 mg/kg.
The problem arose last month when Safeway alerted Maff to the results of tests it had done on its own brand of tinned tomatoes.
Maff's Joint Food Safety and Standards Group issued a warning to environmental health officers, whose tests showed the problem was more widespread. "Maff will carry out an extensive survey of tin in canned tomato products to obtain further information. The results of the survey, including the brand names of products tested, will be made publicly available," Maff said.
Safeway said it was alerted to the problem a month ago when it identified tin levels above the approved limits in its 400g own-brand cans. It removed the products from the shelves and put up posters in all of its 473 stores asking customers to return them. The company said yesterday the action was a "purely precautionary measure".
It said that the tomatoes, if eaten in large quantities, could cause stomach upsets. "Safeway would like to stress that incidences such as this are extremely unusual," it said.
Asda, which has 223 stores, withdrew all 400g tins of its Asda hand-picked plum tomatoes on Wednesday, after Maff tests revealed one batch contained levels of tin above the 200mg limit. "Further testing failed to replicate those results. But as a responsible retailer we withdrew the product from stores when we found out as a precautionary measure," said Asda.
The brands identified with high levels of tin are Safeway canned chopped tomatoes in tomato juice (400g), Tesco Italian premium chopped tomatoes (400g), Princes chopped tomatoes in tomato juice (480g) and Asda hand- picked plum tomatoes (400g).