A report by a consumer group in the U.S. has found that most of the chicken sold in grocery stores could contain bacteria that cause foodborne illnesses.
The group Consumer Reports says it found that 83% of the chickens they tested had one or two of the main bacteria which cause food-borne diseases and says this figure is up 34% from 2003.
However the study has come in for some pretty harsh criticism; the U.S. Agriculture Department (USDA) has referred to it as "junk science", and has questioned the report's methodology saying the study is flawed.
According to Consumer Reports, tests carried out on 525 chickens showed most of the poultry had campylobacter or salmonella.
The chickens included some from leading brands Perdue, Pilgrim's Pride and Tyson Foods, and were purchased at supermarkets, mass retailers, gourmet shops, and natural food stores in 23 states last spring.
Jane Halloran, a policy director for Consumers Union, which publishes Consumer Reports says it demonstrates a very significant deterioration in food safety.
A spokesman with the U.S. Agriculture Department's Food Safety and Inspection Service says the report did not return to all the stores used in the 2003 report and has not stated what type of salmonella was found; it seems one very common strain, Salmonella Kentucky, does not make people ill.
The new report "Dirty Birds", blames the rise in bacteria in chicken to an increase in the presence of the campylobacter bacteria, which can be carried by birds without them becoming ill, but causes diarrhea in people.
Of the chickens tested 81 percent of them were positive for the pathogen, up from 42 percent in 2003.
Consumer Reports says paying more for a chicken which is organic or antibiotic-free chicken, does not increase your chances of getting one free of illness-causing bacteria.
Salmonella causes diarrhea, headache and fever in people and is one of the most frequently reported causes of food-borne illness in the United States.
The USDA says 11.4 percent of 8,000 broiler samples through September of this year tested positive for salmonella, which if it held for the remainder of the year would be down from 16.3 percent in 2005.