A tin of beans, a loaf of bread, and a quick blood test

After moving into dry-cleaning, pharmacies and coffee shops, supermarkets have now decided to include the services of a doctor's surgery. Safeway is offering to test shoppers for up to 150 allergies, including those for bee and wasp stings, dog and cat hairs, pollen, peanuts and house dust mites.

This is the latest move in the increasingly fierce competition between the big supermarket chains. Nurses will be joining shelf-stackers and checkout staff in five selected stores, in London and the Home Counties, to take blood samples which will be sent away to be analysed.

Customers will be charged pounds 12.99 for a single-allergy test, carried out in consulting rooms attached to the stores' pharmacies, and pounds 16.99 for a multiple. The trial will last six months and will be extended if it is successful.

"It's all about extending into other areas," explained a Safeway spokeswoman. "Of the core products in supermarkets, 60 per cent of lines are the same. Customer service is becoming increasingly more important. So we brought in self scanning, creches, coffee shops - and now this."

However, there are concerns that such tests are best left to doctors. "In my opinion an investigation of an allergic reaction in a patient should take place where the full clinical history is known, rather than blanket testing in a store," said Dr Sheila Powell, consultant dermatologist at Churchill Hospital, Oxford. "The question also arises which tests are more reliable and less reliable. If you have a problem you should talk to your doctor who can do an investigation if it is appropriate."

And Erik Brown, publicity officer of the Anaphylaxis Campaign, said: "The kind of people who tend to be aware of allergies are the educated middle-classes who recognise it and do something about it. I don't think this test is going to have much impact on a sprawling council estate. At pounds 17 it's not exactly a social service."