Which food is said to have caused the 1951 'Pont-Saint-Esprit mass poisoning'?

The 1951 Pont-Saint-Esprit mass poisoning, also known as French: 'L'affaire du pain maudit', occurred 15 August 1951, in the small town of Pont-Saint-Esprit in southern France. More than 250 people were involved, including five deaths.

It began in a quiet village where two bakeries tended to the inhabitants’ daily need for bread. The summer of 1951 was unusually wet, and that year’s rye crop was expected to fall short. In August of that year, one of the village bakers received a supply of strangely gray flour, but with the government strictly controlling flour distribution, he had no other means of making that morning’s baguettes and proceeded to bake and sell his wares as usual.

Over the course of a few weeks, 'le pain maudit' (the cursed bread”) wreaked havoc. Within 48 hours, some 230 villagers became violently ill. Initially their reactions to the bread resembled severe food poisoning, with people experiencing nausea and vomiting accompanied by days of insomnia. It was reported that many were experiencing wild hallucinations, convulsions and swollen limbs that felt as if they were burning, causing extremely erratic behavior. Five otherwise healthy people died.

The rash of disturbing actions pointed to ergotism, epidemics of which have been recorded since ancient times. It thrives on rye under certain climate conditions. Lysergic acid, the active component in the fungus, was used to create LSD, which later became a popular recreational drug during the 1960's.