Peanut PCR test

The Food Standards Agency commissioned this work to see if a test could be developed that would detect very small traces of peanuts in commercial food products. It is part of the Agency's ongoing research programme that aims to increase our knowledge and understanding of food allergy and intolerance and protect allergic consumers.

The test shows that it is possible to detect very small traces of peanut (down to 100ng or 1 part in 10 million) in some commercial foods.

The PCR technique is not new. However the new Peanut PCR test has further developed the technique to detect foods causing allergic reactions.

PCR (Polymerase Chain Reaction) is a sensitive test that can be used to detect very small amounts of DNA. The technique has been used to detect GM material in foods or to determine food authenticity such as which species meat samples come from.

Central Science Laboratory (CSL), an analytical laboratory based in York.

Food allergy is a very serious problem for some people and eating even very small amounts of the food to which they are allergic can cause serious adverse reactions (anaphylactic shock) and even death. Therefore it is very important that if peanuts are present in a complex food consumers can be warned about this.

Currently some manufacturers use a phrase like 'may contain nut traces' if they are not certain that their products do not contain nuts. However widespread use of these labels can restrict the choice of foods available to those people with peanut allergy.

The Agency is already discussing with industry ways to reduce the use of labels such as 'may contain'.

The use of this test could help to reduce to need for such labels but at present it has only been developed to detect traces of peanuts. There are other foods that cause allergic reactions, including tree nuts (such as walnut, hazel nut, Brazil nut etc.) and shellfish, and the test would have to be extended to detect these other allergens as well.

The test needs to be developed further to ensure that it works effectively in a other types of foods but in principle its use in unprocessed foods should be possible.

At the moment the test has only been developed to detect peanuts but it could be adapted further to detect other allergens.

Approximately 1 in 200 people are allergic to peanuts, although there is some evidence to suggest that this figure is increasing.

For some people adverse reactions to foods can be mild with tingling of the lips, swelling in the mouth and skin rashes. However for other people the reactions can be very severe with extreme swelling in the mouth and throat, difficulties in breathing, drop in blood pressure, loss of consciousness and even death.

The Agency has an extensive research programme on food allergy and intolerance to improve knowledge and understanding of these conditions and so that we can better protect the interests of consumers with food allergies.

The Agency provides general information to consumers with questions about food allergy and intolerance but we advise anyone who thinks they have an allergy or intolerance to discuss this with their doctor and to have a proper diagnosis. We also tell enquirers about organisations such as the Anaphylaxis Campaign and the Coeliac Society who provide information for consumers.