UK organic certification body the Soil Association has responded with a note of caution to reports last week that a government-funded study had found free-range and organic chickens are twice as likely as battery hens to be contaminated with the food-poisoning bacteria campylobacter.
"Professor Humphrey's [Tom Humphrey, Bristol University] has not yet been completed, peer-reviewed or officially published. The strains of campylobacter collected have not yet been identified so it is impossible to know whether the organic chickens tested contained strains of campylobacter capable of causing food poisoning," said Richard Young, the policy advisor to the Soil Association.
"Humans, chickens and all animals have large numbers of bacteria in their intestines, most of which are not just harmless but are essential to health. Most strains of campylobacter cannot cause food poisoning," he added.
According to the Soil Association, at least one scientific study has demonstrated that chickens which contain large numbers of the non-pathogenic strains of campylobacter are much better able to withstand infection from pathogenic (disease causing) strains.
"Even if further research establishes that some organically reared chickens carry pathogenic strains of campylobacter the Soil Association believes that the lower use of antibiotics in organic poultry farms will make it less likely that such strains are resistant to antibiotics," continued Richard Young.
"The survey was undertaken at an abattoir and we understand that his (Young's) scientists did not visit any organic farms. Further work is required to check that the findings are representative of organic flocks and, if they are not, to establish how the contamination occurred."
"The Soil Association acknowledges that not enough is known about campylobacter and that there is insufficient information on the public health risks associated with different farming systems. More government-funded work is needed," he concluded.
Selected findings from the campylobacter research were presented at a Food Standards Agency meeting on 6 November by Tom Humphrey, Professor of Food Safety at Bristol University.