A Michelin-starred restaurant in Spain has closed while authorities investigate the death of a woman who ate a dish of mushrooms that can be poisonous if not carefully cooked.

María Jesús Fernández Calvo, 46, ordered a rice and morchella fungi dish at RiFF restaurant in Valencia on Saturday.

The optician was celebrating her husband’s birthday at the eatery known for ‘innovative’ cuisine alongside their 10-year-old son.

She died on Sunday morning after bouts of vomiting and diarrhea.

Eleven more customers who ate at Riff on Saturday, including Ms Fernandez Calvo’s husband and son, came down with similar symptoms, Valencia’s medical authority has revealed.

However, it will not be possible to confirm whether she died from poisoning or asphyxiation from particles of vomit in her lungs until an autopsy is carried out.

“We will have to wait...before we can determine whether it was the ingestion of a food that directly caused her death, or whether it prompted a state that led to this fatal outcome,” said regional health chief Ana Barceló on Wednesday.