But they added that previous studies have pointed to a wide range of responses to stress that can trigger drinking.

BBC: Genes may drive stressed-out drinkers

The union says the company has failed to act on a range of staff concerns which include stress, unachievable targets and widespread use of agency workers.

BBC: BT workers go on strike

Steve Wearne, a director at the FSA, said it had called an urgent meeting "of a range of suppliers" on Monday where it would "stress again the responsibility of all food businesses to ensure the food that they sell contains what it says on the label".

BBC: Food Standards Agency calls contamination meeting