Peanuts are one of the most common foods that trigger allergies in people, but a new study suggests the problem is not the peanuts but the dry-roasting process.

Researchers from Oxford University and the University of Pennsylvania injected mice with samples of peanut protein from nuts that were either raw or dry roasted. The mice that got the dry-roasted samples mounted a much more vigorous immune system response than the mice that got raw samples, according to a study in the Journal of Allergy and Clinical Immunology. An intense immune system reaction is a sign of an allergy.

The researchers followed up by feeding the mice various types of peanut extract. Again, the mice that had already been exposed to dry-roasted peanut protein had a greater immune response than the mice exposed to raw peanuts. All of the experiments seemed to suggest something in the dry-roasting process turned harmless peanuts into allergy-inducing comestibles. - L. A. Times