Roasted peanuts are more likely to trigger an allergic reaction than raw peanuts, according to a new study.

An Oxford University research team says chemical changes caused by dry roasting processes may prime the body’s immune system, sparking future allergic reactions, BBC News reported.

The study, published in the Journal of Allergy and Clinical Immunology, exposed mice to peanut proteins through the skin and stomach.

The mice exposed to dry roasted samples had a much stronger immune response than mice given the raw versions. An immune response is triggered when the body is fighting something foreign.

Researchers believe the high temperatures used to roast the nuts may be responsible for the chemical changes that prompt allergic reactions.

“This is the first time, to our knowledge, that a potential trigger for peanut allergy has been directly shown,” Professor Quentin Sattentau, lead researcher said, according to BBC News.

The scientists say more research is needed to determine if humans react the same way.

“However our research is at an early stage and we think that it would be premature to avoid roasted peanuts and their products until further work has been carried out to confirm this result,” Sattentau said.

Click for more from BBC News.