Supermarkets and food producers in the United Kingdom have faced criticism after it emerged that more than seven in 10 fresh chickens on sale across the country are contaminated with campylobacter.

Six percent of packaging also tested positive for the presence of the food poisoning bacteria.

The Food Standards Agency (FSA) tested 1,995 samples of fresh whole chilled chickens sold at U.K. supermarkets and smaller independent stores and butchers. The government body found variations between retailers but said that none are meeting the end-of-production target for reducing campylobacter.

The bug is the most common form of food poisoning on both sides of the Atlantic, with poultry the source of most cases.

Commenting on the new report, Steve Wearne, FSA director of policy, said: "These results show that the food industry, especially retailers, need to do more to reduce the amount of campylobacter on fresh chickens. Although we are only half-way through the survey, 18 percent of birds tested had campylobacter over 1,000 cfu/g, the highest level of contamination, and more than 70 percent of birds had some campylobacter on them. This shows there is a long way to go before consumers are protected from this bug."

Testing by the FSA will continue until February 2015, with a total of 4,000 samples planned to be examined.

The industry and retailers have taken steps recently to tackle campylobacter and that action may not be reflected in the most recent figures, the FSA noted.

For example, Marks & Spencer and its supplier, 2 Sisters Food Group, have developed an integrated program of interventions along the food chain to reduce levels of campylobacter. Another retailer, Asda, and its supplier, Faccenda, are conducting trials of an innovative new steam technology called SonoSteam. And various retailers, including The Co-operative Food, have introduced 'roast in the bag' chickens which help limit cross-contamination by minimising the handling of the raw chicken in the home.