Tesco said the error only lasted a short time, but could not immediately confirm whether any birds from the affected batch were still on sale at its stores

The supermarket giant said this was a "completely unacceptable" mistake caused by a farmer accidentally giving his chickens the wrong feed.

The retailer said the error only lasted a short time, but could not immediately confirm whether any birds from the affected batch were still on sale at its stores.

Tesco issued the apology in response to tests carried out for The Times on corn-fed chicken sold by six supermarkets and upmarket department store food halls.

Scientists at the Department for Environment, Food and Rural Affairs (Defra) Central Science Laboratory in York found the Tesco chicken "was not in keeping with EU regulations", the paper reported.

All the other samples tested were found to have consumed enough maize to justify being sold as corn-fed.

According to Defra's website, the term "corn-fed" is generally understood to mean that the feed formula given during the greater part of the chicken's fattening period must contain at least 50 per cent maize.

Corn-fed chicken, which has a distinctive yellow colour, sells at a premium but has become increasingly popular in recent years as discerning consumers seek out better quality produce.

Source: Daily Mail