Two-thirds of store-bought chickens in the US harbour salmonella and or campylobacter bacteria, the leading causes of food borne disease in the country, a consumer group has claimed.

US consumer group Consumer Reports has claimed to have measured contamination in store-bought chickens since 1998.

This year's survey acknowledged that the figure was a "modest" improvement over 2007's survey.

However, tests still revealed that campylobacter was in 62% of the chickens, salmonella was in 14% and both bacteria were in 9%. Only 34% of the birds tested were clear of both pathogens.

A spokesperson for the group insisted that the latest findings emphasise the need for governmental regulation of the poultry industry.

"The federal government has paid much lip-service to improving food safety, but it is yet to regulate chicken production. Our latest survey again highlights the need for intervention."

According to the Centre for Disease Control and Prevention, 3.4m Americans are infected by salmonella and campylobacter from chicken and other food sources.

"This high level of contamination is clearly unacceptable," the Consumer Reports spokesperson insisted.

Responding to the report, the National Chicken Council (NCC) - which represents US chicken manufacturers - insisted that "chicken is safe".

"Like all fresh foods, raw chicken may have some microorganisms present, but these are destroyed by the heat of normal cooking. Consumers are encouraged to follow the safe handling and cooking instructions printed on every package of fresh meat and poultry sold in this country," the NCC said.