The UK's thousands of household pets may be playing a major part in spreading food poisoning, a food safety expert has warned.

Professor Hugh Pennington is proposing a new study to investigate the sources of campylobacter, the most common type of the bug.

Until now chickens have been assumed to be the main cause of campylobacter - which causes food poisoning in about 500,000 people in the UK each year.

But Professor Pennington said dogs, pet and wild birds, cattle and other animals could also be spreading the bacteria into the human food chain.

People shouldn't be obsessed about this kind of thing... It's basically a question of commonsense

Prof. Hugh Pennington

"We know campylobacter in chickens is a cause of food poisoning - but we do not know if it really is the major cause," said Professor Pennington.

"We cannot be confident, in fact, that chickens are the main source.

"Pets are certainly in the frame of our proposed investigation.

'Fingerprint' bug

"We need to look at the role of pets in spreading campylobacter and see how big a part they play. We just don't know at the moment.

"There are a lot of people looking at how to type campylobacter, how to fingerprint it, so that we can answer this question - how important dogs are.

"People shouldn't be obsessed about this kind of thing. There are many advantages to having dogs. It's basically a question of commonsense."

Prof. Pennington: "Answers needed"

Professor Pennington, from Aberdeen University, said there was no vaccine against campylobacter.

He plans to apply for money from the government and the poultry industry to fund the �250,000 study.

Campylobacter causes stomach upsets and other minor illness for a couple of days in most cases.

But in some people it can lead to severe complications.

Professor Pennington will give evidence on the threat posed by campylobacter to the House of Lords Science Select Committee on 16 July.