The Consumers Union said the figure was an improvement from the 80 per cent found in tests in 2007 but "still far too high." It urged the government to issue stricter food-safety rules. The group began testing for bacteria in store-bought chicken in 1998, according to The Vancouver Sun.

Salmonella, the most common cause of food-borne illness, was found in 14 per cent of the chickens and campylobacter, the No 2 cause, was in 62 per cent. Nine percent of chickens contained both bacteria. Consumers Union bought the chickens at 100 retailers in 22 states last spring.

The Agriculture Department, which is in charge of meat safety, reported a salmonella rate of 5 per cent in its samples taken at packing plants from 1 April - 30 June. Its researchers say cold water baths and other antimicrobial can reduce the presence of campylobacter to 11 per cent.

A USDA spokesman said salmonella levels are down sharply from 16 per cent in 2005 due to its meat safety programmes and a similar pathogen reduction programme "will be launched soon" for campylobacter.

Consumers Union said it tested the chickens later in the retail chain than USDA and pointed to other studies that found high levels of campylobacter at processing plants. It said USDA should set maximum limits on campylobacter contamination.

"Consumers still need to be very careful in handling chicken, which is routinely contaminated with disease-causing bacteria," said Dr Urvashi Rangan, Director of Technical Policy at Consumers Union.

"Chicken is safe. Like all fresh foods, raw chicken may have some microorganisms present, but these are destroyed by the heat of normal cooking," said the National Chicken Council, a trade group.

Like the consumer group, the chicken council urged home cooks to refrigerate or freeze raw meat, cook it to at least 165 degrees Fahrenheit (74 degrees Celsius) and to promptly store leftovers.