Scientists have found that two thirds of chickens in UK supermarkets are contaminated with E.coli.
The study from Public Health England and the Department for Environment, Food and Rural Affairs (Defra) claimed that 78 per cent of chickens sold in high streets in England contained an antibiotic-resistant E.coli strain. This figure dropped to 53 per cent in Scotland and 41 per cent in Wales.
Read more: Your bagged salad is a Salmonella risk
The appearance of resistant strains of E.coli in chicken has been blamed on the fact that chicks are fed antibiotics - meaning they are only affected by resistant strains of the bug. Health experts said this would make it more difficult to treat anyone who becomes ill from the bug.
Dr Mark Holmes, reader in microbial genomics at Cambridge University, told the Daily Mail: "People do get food poisoning and every time someone falls ill, instead of just getting a food poisoning bug they might also be getting a bug that is antibiotic-resistant.
"If they end up developing sepsis or a urinary tract infection they may well find they have a bug that is resistant to the first-choice antibiotic. By the time they get on to the right antibiotic the bug could be out of control. It can even lead to death."
The study comes after supermarket salad bags were found to be a breeding ground for Salmonella, which could attach to salad leaves and could not be washed off.