When you think about mushroom poisoning, the first to come to mind are the death cap and fly agaric mushrooms. Many people don’t know that edible mushrooms can also cause gastrointestinal problems. Consuming spoiled mushrooms, preparing them incorrectly or, for certain mushrooms, consuming alcohol at the same time, can result in symptoms of poisoning. In addition, mushrooms are difficult to digest.
A study by Tox Info Suisse determined that symptoms in adults arise most frequently after consuming edible mushrooms.
Edible mushrooms: unpleasant gastrointestinal symptoms
Tips for safe mushroom preparation – avoid gastrointestinal symptoms
Savoury Mushroom Skillet Foto: razieh bakhtom auf unsplash
Mushrooms are rich in protein and highly perishable: Proper storage and reheating of leftovers
Mushrooms will spoil especially quickly if they are stored in plastic bags or are not refrigerated. You can even find examples of mushrooms beyond their optimal freshness in retail. Gastrointestinal symptoms such as abdominal pain, nausea, vomiting and diarrhoea can be caused by consuming spoiled mushrooms. These symptoms usually occur within 4 hours of eating the mushrooms.
Cultivated button mushrooms and other cultivated mushrooms can be stored in the refrigerator for several days. Wild mushrooms need to be prepared and eaten within 24 hours. Otherwise you need to freeze them. Heating up leftovers of mushroom dishes is fine within 24–48 hours. However, only if the leftovers have been cooled quickly and stored in the refrigerator.
Do not eat any raw mushrooms
On their website, the Swiss association of official mushroom control bodies (Vapko) recommends that you do not eat raw mushrooms. Even the popular button mushroom can cause gastrointestinal problems in sensitive people when consumed raw.
Stick to the cooking times and blanch if needed
The majority of mushrooms need to be cooked for at least 10 minutes, some species even need 20 minutes or to be blanched in advance. Before cooking the mushrooms further, the cooking water must be poured away. If you don’t do this, there is a risk of vomiting and diarrhoea 1–4 hours after your meal.
Mushroom species with a specific preparation method (list not exhaustive):
Cooking time at least 20 minutes
- Dotted stem bolete (Neoboletus erythropus)
- Blusher mushroom (Amanita rubescens)
- Bay bolete (Imleria badia)
- Olive brittlegill (Russula olivacea)
Blanch, throw away cooking water
- Honey fungus and dark honey fungus (Armillaria mellea and ostoyae)
- Clouded funnel cap (Clitocybe nebularis)
This mushroom is no longer on the official Vapko edible mushroom list.
The extremely popular parasol mushroom (Macrolepiota procera) is particularly trick to prepare correctly:
This impressive, gilled mushroom has a cap size of up to 25 cm and is also commonly called giant parasol. Another name could be due to its cooking method: Schnitzel mushroom. The cap features a tough, hard centre, which is often not cooked for long enough, in comparison to the soft, almost fluffy flesh forming the edges of the cap. Cutting the cap in half can help. The cooking time depends on the method. Before eating, you should check that all parts of the cap are cooked through.
Mushrooms and alcohol: Coprine syndrome
Some mushrooms result in outbreaks of sweating, rashes and circulatory problems when consumed together with alcohol. The culprit could turn out to be a glass of wine or a cough syrup containing alcohol (even 3–4 days after actually eating the mushrooms). We call this coprine syndrome. The common ink caps (Coprinus atramentarius) or the freckled dapperling (Echinoderma asperum) are known culprits.
Prevention
- Always have your mushrooms checked by a mushroom inspection body. The mushroom inspection body will also advise you on the correct storage and preparation and has useful mushroom foraging tips.
- Follow Vapko’s recommendations for eating mushrooms.
- Clean mushrooms thoroughly before preparing and make sure you know how to cook them properly.
- Generously cut away any bite marks and reject any spoiled mushrooms – even if it pains you to do so.
- Use mushrooms that are as fresh as possible.
- Keep leftovers of mushroom dishes in the refrigerator, never at room temperature.
Action in the event of gastrointestinal symptoms after eating mushrooms
Mushrooms not checked by a mushroom inspection body
- Contact Tox Info Suisse immediately.
Mushrooms checked by a mushroom inspection body
- Ensure a sufficient intake of fluids.
- Children, the elderly, and those with pre-existing medical conditions should seek medical attention for anything more than mild symptoms.
Further information
Additional articles on the topic by Tox Info Suisse:
Expert articles:
Updated October 2024