Europe?s food safety agency has recommended that baby food manufacturers change the lids on their jars as soon as possible because of cancer concerns over a chemical found in some food packed in bottles and jars.

The chemical, semicarbazide, has been found in very small quantities in certain foods packaged in jars with metal lids incorporating plastic vacuum seals, a type of packaging used worldwide for more than 20 years.

Semicarbazide, or SEM, belongs to a family of chemicals known to cause cancer in animals. One study has shown it can cause tumors in mice. No human studies have been conducted. The European Food Safety Authority is the first organization to have taken a close look at the risks posed by the chemical.

Although the amount in food is uncertain and its human health effects unknown, scientists investigating on behalf of the European food agency concluded that the danger is very slight.

A baby?s estimated daily intake of SEM, based on the concentrations found in the infant food, was at least 40,000 times less than the dose given to the mice in the tumor study.

Experts believe it would be prudent to reduce the presence of semicarbazide in baby foods as swiftly as technological progress allows. It is also recommended the industry change the lids for other products, after baby foods have been tackled.

Bottled foods found to have the semicarbazide included fruit juices, jams, sterilized vegetables, pickles, baby food, mayonnaise, mustard, sauces and ketchup. Baby food had by far the strongest concentrations, probably because the contact between the food and the seal is more significant ? the jars are small but the cap still has to be big enough to fit a spoon in.