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Are potatoes with a greenish spot poisonous or edible?


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

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

Potato dish poisoning case

Potatoes with shoots and green spots can contain the dangerous substance solanine and should therefore be better sorted out. This is indicated by the Federal Institute for Risk Assessment (BfR) on the occasion of a poisoning event by a potato dish. Depending on the amount ingested, solanine can lead to intoxication with symptoms such as dizziness, headache, stomach pain, nausea and vomiting as well as scratching and burning in the throat. In high doses, the substance can even be fatal, according to experts.

Do not eat green and strongly germinating potato tubers

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

"Only a few cases of poisoning from potato dishes have been known and documented in the last 100 years," explains BfR President Professor Dr. Dr. Andreas Hensel in a message.

"In order to avoid health risks, green and strongly 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 reminds of the following usual recommendations in connection with the storage and preparation of potatoes:

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

Green areas and so-called "eyes" in potatoes should be removed generously. If consumers want to eat the skin, only uninjured, fresh potatoes are suitable.

Potato dishes should not be consumed if they have a bitter taste. Young children in particular should not eat unpeeled potatoes.

Consumers should not reuse potato boiling water. Frying fat for potato products should be changed regularly

Not inconsiderable number of unreported cases

Glykoalkaloids are natural ingredients that are found in nightshade plants such as. 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-chaconine. They are used by 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 cases of poisoning, additional disturbances in consciousness, very rarely until complete loss of consciousness, as well as further disorders of brain function, breathing or circulation can occur.

Individual fatal poisonings have been reported in the literature. However, no deaths from glycoalkaloid poisoning have been reported in the past 50 years.

In addition, only a few cases of poisoning from the past 100 years are known and documented. Due to the non-specific symptoms, especially in the case of minor poisoning, there could be a not inconsiderable number of unreported cases.

Glyco-alkaloid content of table potatoes with less than 100 mg per kg fresh weight

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

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

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

In view of the current incomplete data situation, these recommendations are to be regarded as provisional.

So far, potatoes with a glyco-alkaloid content of up to 200 mg per kg have generally been classified as harmless.

In order to improve the data situation with regard to the existing glycoalkaloid contents in commercially available table potatoes, the BfR has suggested carrying out corresponding tests (food monitoring). (ad)

Author and source information

Video: Is it Okay to Eat Green Potatoes? (August 2020).