Approximately 1 in 200 people in the UK are allergic to peanuts, and evidence suggests this figure is increasing.

While some people develop only minor symptoms, others can go into anaphylactic shock, putting their lives in danger. Approximately 10 people a year die in this way.

The only safe option for these people is to avoid eating peanuts, but this is not always very easy, as processed foods may become contaminated by nuts during the manufacturing process.

This new test is a small but important step forward in our work to protect people who are affected by food allergy Dr Andrew Wadge

Now scientists working for the Food Standards Agency (FSA) have developed a test which can detect even the tiniest amount of peanut in food products.

The test, developed at the Central Science Laboratory in York, is so sensitive that it can detect traces of peanut as small as one part in 10 million.

It can also distinguish peanuts from other types of nuts, even within processed products.

This means that in the future manufacturers should be able to say for sure if their product contains even a few parts per million of peanut.

Uncertain

At the moment, manufacturers are often unsure whether or not their products actually contain allergens as a result of contamination from another production line, or through contamination of raw ingredients.

Because of this uncertainty, they use phrases on the products, such as 'may contain', to warn those people with allergies.

Dr Andrew Wadge, acting director of food safety policy at the FSA, said: "This new test is a small but important step forward in our work to protect people who are affected by food allergy.

"Further research is needed to explore whether the test can be adapted to detect other common food allergens.

"However it is hoped that the work could lead to the development of a process that food businesses will be able to use in their production methods."

The test, known as PCR, works by detecting peanut DNA in food products.

It was tried out on a small number of food products found in sale on shops such as biscuits, cakes, chocolate and sausage.

Eating out

David Reading, director of the Anaphylaxis Campaign, told BBC News Online the test would be very welcome - mainly because it might help to reduce people's anxiety levels.

However, he said: "Even with a test such as this we would still urge people to be very vigilant, and never to take anything for granted."

Mr Reading said the biggest problem for people who suffer from peanut allergy was ordering food in restaurants without realising it contained nuts.

Martin Paterson, deputy director of industry body the Food and Drink Federation, said: "A reliable and practical test method could help manufacturers to assess risk but cannot eliminate the possibility of adventitious contamination, which has to be addressed by good manufacturing practices."

The Anaphylaxis Campaign runs a helpline on 01252 542029.