Are potatoes with a greenish spot poisonous or even edible?

Dangerous solanine in potatoes: Sort out green and strongly germinating tubers

The Federal Institute for Risk Assessment (BfR) reminds on the occasion of a poisoning case by a potato dish of a proper handling of potatoes. Green and highly germinating tubers should definitely be sorted out because they can contain the dangerous substance Solanin.

Poisoning case by a potato dish

Potatoes with shoots and green spots may contain the dangerous substance Solanin and should therefore be better sorted out. This is indicated by the Federal Institute for Risk Assessment (BfR) on the occasion of a poisoning case by a potato court. Depending on the amount absorbed, solanine may cause poisoning with symptoms such as dizziness, headache, stomach ache, nausea and vomiting, and scratching and burning in the throat. At a high dose, according to experts, the substance may even be fatal.

Potatoes with shoots and green spots should not be eaten. They could contain the substance Solanin, which can lead to poisoning. (Image: Rainer Fuhrmann / fotolia.com)

Do not eat up green and strong germinating potato tubers

Glycoalkaloids, including solanine as an important representative, are natural ingredients in the potato.

"From the last 100 years, only a few cases of poisoning by potato dishes are known and documented", explains BfR President Professor Dr. med. Dr. Andreas Hensel in a message.

"To avoid health risks, green and strong germinating potato tubers should not be consumed."

Storage and preparation of potatoes

In order to keep the intake of glycoalkaloids as low as possible, the BfR recalls the following usual recommendations in connection with the storage and preparation of potatoes:

Potatoes should be stored cool, dark and dry. Old, dried, green or strong germinating potatoes, as well as potato peels as snacks, which consist mainly of potato peels, are not suitable for consumption.

Green spots and so-called "eyes" in potatoes should be removed generously. If consumers want to eat the bowl, then only undamaged, fresh potatoes are suitable for this purpose.

Potato dishes should not be consumed if they have a bitter taste. Especially small children should not eat unpeeled potatoes.

Consumers should not use the cooking water of potatoes again. Frying fat for potato products should be changed regularly

Not insignificant dark figure

Glycoalkaloids are natural ingredients that are used in nightshade plants such. B. potatoes are included. They accumulate in particular in green, germinating and damaged potatoes as well as in potato peels.

The potato contains in particular the two glycoalkaloids α-solanine and α-chaconin. They serve the plant to ward off pests and pathogens.

In humans, slight poisoning is manifested by nausea, abdominal pain, vomiting and diarrhea, sometimes accompanied by fever.

In severe poisoning cases may also cause disturbances of consciousness, very rarely to complete loss of consciousness, as well as other disorders of brain function, respiration or the circulation.

Single fatal poisonings have been reported in the literature. However, over the past 50 years no deaths due to poisoning by glycoalkaloids have been reported.

In addition, only a few poisoning cases from the last 100 years are known and documented. Due to the non-specific symptoms, especially in the case of lighter poisonings, however, a considerable number of unreported cases could exist.

Glycoalkaloid content of table potatoes at less than 100 mg per kg fresh weight

On the occasion of a case of poisoning by a potato dish, in which a family fell ill in November 2015, after consuming a potato dish containing high levels of glycoalkaloids, the BfR assessed the consumption of glycoalkaloids via table potatoes.

On the basis of the current state of knowledge, the BfR derives a preliminary No Observed Adverse Effect Level (NOAEL) of 0.5 mg (mg) of glycoalkaloids per kilogram (kg) of body weight per day.

This corresponds to the highest dose at which no adverse health effects were observed. To avoid exceeding the NOAEL, the glycoalkaloid content in table potatoes should be less than 100 mg per kg fresh weight.

These recommendations are provisional given the current incomplete data.

So far, potatoes with a Glykoalkaloidgehalt of up to 200 mg per kg are generally classified as harmless.

In order to improve the data on the existing glycoalkaloid content in commercially available table potatoes, the BfR has initiated the conduct of appropriate investigations (food monitoring). (Ad)