by JAMES CHAPMAN, Daily Mail

Organic chickens are three times as likely as battery birds to be infected with a food poisoning bug which can cause paralysis and even death, tests suggest

A study by Danish scientists of 22 organic flocks found all of them were contaminated with the campylobacter bug, compared to a third of those kept in batteries.

The bacterium has replaced salmonella as the biggest cause of food poisoning in the UK, although it is destroyed by thorough cooking. Some 54,000 cases were reported in Britain last year.

The findings, published in the journal Letters in Applied Microbiology, will alarm the millions of people who have switched to organic produce because they believe it is healthier than intensively-produced food. Dr Karl Pedersen, who led the study at the Danish Veterinary Laboratory in Aarhus, said the findings were 'unwelcome news', adding: 'The difference is far higher than we expected.'

He believes organic birds are more likely to become infected because they can roam outside and come into contact with the infected faeces of wild animals.

Organic chickens are also kept alive for twice as long as intensively reared birds, so they have more time to become infected, he said.

The findings offer even stronger evidence than a study by the UK's Food Standards Agency which examined chickens from supermarkets and butchers and found campylobacter in 51 per cent of intensively-reared birds, 61 per cent of organic birds and 68 per cent of free-range birds.

Patrick Holden, director of the Soil Association, which promotes organic farming, questioned whether conditions in Danish flocks would be the same as in Britain. 'Because of variation in organic farming standards across the EU it would be difficult to use this research to make a judgment on the situation in the UK,' he said.

'The standards we insist on for poultry given the Soil Association mark includes low-stocking densities which make the spread of campylobacter more difficult.

'It is also possible antibiotics used in non-organic poultry in the Danish research suppressed the detection of infection.'