One in five supermarket chickens is contaminated with campylobacter, according to an investigation – spurring claims of "scaremongering" by a retail consortium.

The study involved poultry bought from nine of the UK’s major supermarkets by the Which? consumer group.

As well as 18% of the samples containing campylobacter, 17% of them were contaminated with listeria, with salmonella present in 1.5% of the 192 chickens tested.

Whole chickens and chicken portions – standard, free range and organic, and all reared in the UK – were tested.

Sky News contacted all nine of the supermarkets tested in the survey. Most of them referred us to the British Retail Consortium (BRC).

The BRC’s food director Andrew Opie said: "Which? is scaremongering. Campylobacter is completely killed by normal cooking so providing people prepare chicken properly and follow sensible hygiene practices they’re at no risk."

There’s always a risk; especially with cross-contamination in home and food service kitchens.

In 2009, the UK Food Standards Agency (FSA) found (in a similar but not directly comparable test) that 65% of chickens were contaminated with campylobacter at the point of sale.

FSA said that tackling campylobacter was a “key issue” but warned that, despite the reduction in contamination, seasonal variations made it difficult to assess the merits of the decline.

Campylobacter was responsible for over 371,000 cases of food poisoning, including 88 deaths in the UK in 20009.

Which? executive director Richard Lloyd said: "We want to see the risk of contamination minimised at every stage of production, because for far too long consumers have been expected to clean up mistakes made earlier in the supply chain."

British Poultry Council chief executive Peter Bradnock said: "This report makes it clear that chicken is a safe and healthy product when properly cooked. These welcome findings show a big reduction in campylobacter presence on chicken, demonstrating the effectiveness of the biosecurity measures being taken by producers and processors against this naturally occurring bacteria."

Lidl issued a separate statement to Sky News saying: "All farms used to produce our fresh poultry range are members of the Assured Food Standards scheme for poultry, commonly known as the Red Tractor scheme, and are subject to independent third-party audits.

So what.

And journos repeated bad UK food safety advice to cook chicken until the juices runs clear: color is a terrible indicator of food safety in eat. Use a tip-sensitive digital thermometer and stick it in.