Tesco, Sainsbury’s and Marks & Spencer have launched inquiries into chicken supplies after an exposé of alleged hygiene failings in the poultry industry.

A five-month Guardian investigation claims to have exposed flouting of strict hygiene standards that prevent the contamination of chicken in factories and farms.

Measures have been put in place to prevent chicken being contaminated with the potentially fatal campylobacter bug, which the Guardian claims is now present in two-thirds of chicken sold in the UK.

The Food Standards Agency (FSA) has reportedly decided to shelve a commitment to name and shame supermarkets and processors for their campylobacter rates after a “pushback” from industry.

The Guardian claims the decision to suppress communication of the results came from Number 10 after fears it would cause a health scare.

The investigation focused on two of the UK’s largest poultry processors, 2 Sisters Food Group and Faccenda.

Factories owned by the two companies supply Tesco, Asda, Sainsbury’s, Aldi, M&S, KFC and Nando’s.

The campylobacter bug is killed by thorough cooking, but is still said to make 280,000 people in the UK ill and cause 100 deaths each year.