There is no discernible difference in salmonella levels between free-range, organically produced poultry and conventionally produced birds, an Agricultural Research Service scientist has found.

ARS microbiologist J. Stan Bailey of the Poultry Microbiological Safety Research Unit at the Richard B. Russell Research Center in Athens, Georgia, examined 110 processed free-range chickens from three organic producers and found that about 25% of the chickens tested positive for salmonella. Chickens raised conventionally had about the same levels.

Bailey, who presented his findings recently at the annual meeting of the American Chemical Society, in Philadelphia, said the decision to purchase free-range chickens should therefore not be based on the belief that such a chicken is microbiologically superior.

Salmonella, an intestinal parasite that can cause diarrhoea, fever and abdominal cramps, is commonly transmitted by undercooked or uncooked foods. According to the US Centers for Disease Control and Prevention, about 40,000 cases of salmonella infection are reported in the US each year. However, many milder cases are not diagnosed or reported, so the actual number of infections may be up to 30 times greater.

The Agricultural Research Service is the chief scientific research agency of the US Department of Agriculture.