SEVEN in 10 of chickens sold in the UK are infected with the potentially deadly campylobacter bug, it was revealed today.

Campylobacter contamination of fresh shop-bought chickens has significantly increased since August, with every major retailer failing to meet targets to reduce the food poisoning bug.

The Food Standards Agency (FSA) said the cumulative results from the first two quarters of its year-long survey of fresh chickens found 70% tested positive for the presence of campylobacter, up from 59% in August.

Almost a fifth of all chickens (18%) tested positive for the bug above the highest level of contamination, or 1,000 colony forming units per gram (cfu/g), and 6% of packaging tested positive - up from 4% in August.

The FSA also named rates among retailers for the first time, revealing that Asda sold the highest percentage of chickens contaminated with campylobacter at 78%, with 28% showing the bug above the highest level of contamination and 12% of packaging testing positive.

Almost three-quarters of chickens (73%) sold by the Co-operative tested positive, followed by Morrisons, Sainsbury's and Waitrose (69%), Marks & Spencer (67%) and Tesco (64%).

Individual figures for the discounters Aldi, Lidl and Iceland were not reported because their market share was based on 2010 figures and deemed too small, but the overall rate of campylobacter contamination among all retailers other than the major supermarkets was 76%.

The FSA said Tesco was the only major retailer which had a lower incidence of chicken contaminated with campylobacter at the highest level compared with the industry average.

Asda was the only major retailer with a higher incidence of contaminated chicken.

However, the FSA said the results suggested that none of the retailers was achieving the joint industry end-of-production target for reducing campylobacter.