A woman has died after eating at a Michelin-starred restaurant in the Spanish city of Valencia.

María Jesús Fernández Calvo, 46, is believed to have ordered a rice and morchella fungi dish at RiFF, which has now been closed to the public until an investigation has revealed the cause of death.

Eighteen other diners including her husband and 12-year-old son were made mildly ill.

Ms Calvo was reportedly celebrating her husband’s birthday. She died on Sunday morning after suffering diarrhoea and vomiting.

Regional health chief Ana Barceló sent her condolences to the family and said that an investigation was underway.

Do you know your mushrooms? Show all 8 1 /8 Do you know your mushrooms? Do you know your mushrooms? Oyster So subtle, these work best as part an assortment, and are a good choice to accompany fish. A splash of rice wine in the cooking enhances their flavour. The more flavourful king oyster, also known as eryngii, available in Waitrose assortments, has a big, fat stalk, which is delicious sliced thinly and sautéed in butter, and not overwhelmed by mixing with other varieties. Rex Do you know your mushrooms? Shiitake Something of a Marmite item, given their slightly rubbery texture, these work best in oriental dishes; try slicing into miso soup or stir-fries of beansprout and pak choi. They can be combined with other oriental varieties, including oyster mushrooms – which provide the good looks to complement shiitakes' rich flavour – and tiny enoki, which need separating from their clump before being cooked for a minute or less. Rex Do you know your mushrooms? Ceps The king of mushrooms has such a meaty flavour that it could substitute for beef in a vegetarian dish. Also known as penny buns, they are rarely seen in shops, but more available in the wild than commonly realised. Hunting for your own is safe, says Dan Grigg, executive chef at Langley Castle Hotel in Northumberland, who picks his own: “No poisonous mushrooms look similar to ceps, which grow close to trees and can also be found under low ground cover and bushes,” he explains. As ceps may conceal maggots within, cleaning with a toothbrush before a bath in warm salty water is strongly advised pre-cooking. They're also available as dried porcini, the Italian name for them, in supermarkets; when soaking to reconstitute, always save the water, which lends great depth to a mushroom risotto. Rex Do you know your mushrooms? Girolles A late-summer mushroom, these grow in Scotland and are sold by specialist retailers including Turnips and Paul Wheeler in Borough Market, some branches of Tesco, and online from Fine Food Specialists . Gloriously golden, with a peppery taste, they are perfect for adding colour to a dish of roast game, sautéed whole on their own, or combined with other small wild mushrooms such as chanterelles. Rex Do you know your mushrooms? Button Since chestnuts and portobello became commonplace, button mushrooms have fallen out of fashion. Yet nothing works so well in a coq au vin or other winey stew for aesthetic appeal. Button mushrooms should be trimmed of protruding stalks, briefly sautéed in butter and held back until 15 minutes before the end of cooking time, when they can be added to simmer with whole, sautéed pearl onions. Tiny chestnut mushrooms have recently surfaced in supermarkets to add a fuller flavour quotient. Rex Do you know your mushrooms? Chestnut This flavourful species is now as affordable and ubiquitous as the less tasty white ones, which inexplicably lead the market. Halve and sauté in butter to serve with steak, or add a splash of double cream and chopped tarragon and heap on buttered toast, perhaps with some whole white button and sliced yellow oyster mushrooms tossed in for visual and textural variety. Wet polenta or tagliatelle can be substituted for the toast. Rex Do you know your mushrooms? Morels Just when you think it's all over for mushrooms, in the spring along come fresh morels (available from Fine Food Specialists, which sells dried morels all year round). These mushrooms are delicious when combined with chicken pieces that have been sautéed with chopped shallots for 40 minutes, then stewed gently for a further 10 minutes with the morels, a touch of double cream and a sprinkle of chopped tarragon. Brilliant served on a bed of fresh pasta. Do you know your mushrooms? Portobello These are meatier than other varieties and a suitable shape for stuffing. Mix copious amounts of chopped parsley and garlic into breadcrumbs, pack into the cup, trim the stalks, season and dot with salted butter before baking. They're now also available in a smaller size, which is very good served whole as an accompaniment to beef or game. Rex

“We’ve conducted a primary inspection of the establishment and everything appears to be normal,” she told Las Provincias newspaper. “Analytical tests will now be carried out on the food products.”

Samples of ingredients from the restaurant have been sent to Spain’s National Institute of Toxicology and Forensic Science.

Morchella, or true morel, is popular in early spring. They are normally dried out and then well-cooked in order to destroy any presence of the toxin hydrazine.

However, there are several lookalike species known as false morels, which can be lethal.

Chef and owner of the restaurant Bernd Knöller said in a statement: “Regardless of the reason that may have caused this situation, I want to convey my deep regret for what happened, hoping that soon all these facts can be clarified.”

He added: “I have made the decision that the restaurant remains closed until the causes of what happened are established and the activity can be resumed with full guarantees for both staff and all customers.”