Eating out can often be a difficult experience for people with food allergies but researchers now have produced something that could help with that.

Scientists have developed what they call a new “portable allergen-detection system” that looks like a keychain and they say it could help prevent trips to A&E.

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Reaction to food allergies can range from a mild rash to life-threatening anaphylaxis.

Allergy food.
(Margouillatphotos/Getty Images)

Most people manage their condition by avoiding allergens such as nuts, fish, eggs or other products that cause a reaction, but this is not always possible as food can be mislabelled or cross-contaminated.

Researchers Ralph Weissleder, Hakho Lee and their colleagues wanted to develop something that was more consumer-friendly, so they created the $40 (£30) portable device which they called the integrated exogenous antigen testing (iEAT).

The device comes in two parts – an electronic keychain reader for sensing allergens that wirelessly communicates the results to a smartphone and a handheld gadget to extract allergens.

Peanut allergy.
(Professor25/Getty Images)

The researchers say the prototype was able to detect five allergens in less than 10 minutes – “one each from wheat, peanuts, hazelnuts, milk and egg whites, at levels even lower than the gold standard laboratory assay”.

Conventional methods require extensive lab tests which can be slow.

Food allergy keychain.
(The American Chemical Society)

Tests on restaurant food samples showed allergens in unexpected places, like, for example, gluten in salad and an egg protein in beer.

The prototype has been designed to detect five allergens but the researchers say the device could be expanded to test for additional compounds, including other allergens and non-food contaminants such as pesticides.

The research is published in the journal ACS Nano.

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