TV chef Antony Worrall-Thompson has defended his claim that a little bit of dirt in food does no harm.

A row erupted yesterday when Michael Mackenzie, director general of the Food and Drink Federation, accused him and Sir Terence Conran of encouraging poor hygiene by suggesting that "dirt is healthy". But Mr Worrall-Thompson, of Shiplake, near Henley, stood by his belief that the "good earth" contained minerals and that the nation's obsession with being squeaky clean was having a detrimental effect on our immune systems.

"That's not saying that my restaurants are not absolutely clean," the father-of-two added. "Obviously, we wouldn't break the rules on hygiene. But we have got to ask ourselves why there is so much food poisoning, allergies and food intolerances. I think compared with all the chemicals and antibiotics pumped into our food, a little dirt in your organic vegetables is not going to hurt you."