Peanut allergy is on the increase

Approximately one 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.

Food engineers have found that the maturation, curing and roasting of peanuts increases their potential for triggering anaphylactic shock.

And they believe modification of these processes may make them safer.

It assumes that the native nut contains nothing which would cause an allergic reaction Dr Pamela Ewan

However, it is also likely to make them considerably less tasty.

The processing procedure is designed to create sugars and proteins that give roasted peanuts their distinctive flavour.

However, New Scientist magazine reports that a team from the US Department of Agriculture's Southern Regional Research Center in New Orleans has discovered these same sugars and proteins are the very substances that are likely to trigger anaphylactic shock.

The processing procedure involves three stages.

The first, maturation, simply involves leaving the peanuts to ripen in the field.

This is followed by curing, which involves dehydrating the nuts by warming them to between 35 and 70�C.

Finally, they are roasted at around 160 �C for about 20 minutes.

Tests

At each of these stages, the researchers tested the nuts to assess how likely they were to trigger an allergic reaction.

They found each step of the process created compounds made up of both proteins and carbohydrates that are thought to cause the problem.

They believe that simple modifications, such as curing below 60C, could reduce the production of these compounds, and thus reduce the risk of triggering anaphylactic shock.

The key will be to achieve this without losing too much of the flavour.

Dr Pamela Ewan, a consultant allergist at Addenbrooke's Hospital, Cambridge, told BBC News Online: "Theoretically this might work, but it would be a patchy business and it assumes that the native nut contains nothing which would cause an allergic reaction, which I don't know is correct."

Dr Ewan said other researchers were working to modify the structure of the protein in peanuts thought to trigger most cases of allergic reaction.

However, she said this might not work, as other proteins were also thought to be implicated.

A third method under development was to create an antibody to neutralise the allergic response before it could take hold.

The results will be published in the Journal of Agricultural and Food Chemistry.