FSA News, 22 August 2002
Tin levels in canned foods are lower than five years ago and are well within
regulatory limits, according to a Food Standards Agency survey.
Of the canned fruit and vegetables and tomato-based products tested, 99.5% contained tin concentrations below 200 milligrams per kilogram (mg/kg). This is the maximum legal amount of tin that can be present in canned foods.
A total of 400 different samples were tested between December 2000 and August 2001.
Relatively high levels of tin were found in some samples when canned fruit and vegetable products were last surveyed in 1997, and tomato products in 1999.
In the latest survey, only two products were found to contain levels of tin above the legal limit: one sample of gooseberries and one of spaghetti in tomato sauce. Manufacturers and suppliers voluntarily withdrew these affected batches from store shelves after the Agency notified them. They also issued notices in stores and the national press asking consumers to return the products.
Most foods contain very low concentrations of tin. Canned foods may contain higher levels because the tin coating used to protect the steel body of the can from corrosion can slowly transfer into food. No long-term health effects are associated with consuming tin. But it can cause stomach upsets such as nausea, vomiting, diarrhoea, abdominal cramps and bloating in some sensitive people at levels above 200 milligrams per kilogram.
Most of our dietary intake of tin (94%) comes from canned fruit and vegetables.
Reducing tin levels in canned foods
The Agency has worked with the food industry and enforcement officials to find out the causes of tin contamination in canned foods and to minimise the likelihood of high levels.
It commissioned the survey to get up-to-date information on tin levels in canned food and to see if moves to reduce tin levels were having any effect. The survey confirms that introducing cans that are fully lacquered on the inside to contain acidic foods has helped to control and reduce tin levels.
The 200 milligram per kilogram limit is supported by the Committee on Toxicity
of Chemicals in Food, Consumer Products and the Environment (COT). This committee
gives the FSA and other Government departments independent expert advice on
chemical safety in food.