A study highlighting the dangers of sodium benzoate has put further pressure on the industry to reformulate products.

Research from Sheffield University concluded certain carbonated beverages containing the preservative could cause cirrhosis and degenerative diseases, such as Parkinson's.

The Grocer revealed in April that the FSA was reviewing an earlier study that linked sodium benzoate, or E211, to health problems in children.

"The food industry will say these compounds have been tested and are completely safe," said Professor Peter Piper, the author of the Sheffield report. "By the criteria of modern safety testing, the safety tests were inadequate."

MPs are calling for an urgent investigation into the effects of the preservative, which is also found in some sauces and pickles.

A spokeswoman for the FSA said that sodium benzoate was approved for food use after a long and careful process of evaluation.