The German Federal Institute for risk assessment (BfR) said green and strongly germinating potatoes should not be consumed to avoid health risk.
Glycoalkaloids, of which solanine is an important derivative, are natural ingredients of the potato, but ingestion of high amounts can lead to poisoning.
Illness after eating potato-based dishes
In November 2015, cases of illness were observed in a family related to the consumption of potato dishes.
Investigations revealed the potatoes had a content of glycoalkaloids at 236 milligrams (mg) per kilogram (kg). Specifically, the glycoalkaloids α-solanine (141 mg per kg) and α-chaconine (95 mg per kg).
BfR advice
- Potatoes should be stored in a cool, dark and dry place
- Old, dried up, green or strongly germinating potatoes and potato peels as snacks consisting of potato peelings, are not suitable for consumption
- Green parts and so-called “eyes” should be removed
- If consumers also want to eat the skin, only undamaged, fresh potatoes are suitable
- Potato dishes should not be eaten if they have a bitter taste
- Small children in particular should not eat unpeeled potatoes
- Consumers should not reuse the water in which potatoes have been boiled
- Deep-frying fat for potato products should be replaced regularly
Potato salad had a slightly lower glycoalkaloid content of 124 mg per kg.
Until now, potatoes with a glycoalkaloid content of up to 200 mg per kg had been considered safe.
Based on available knowledge, the BfR has set a provisional NOAEL (No Observed Adverse Effect Level) of 0.5 mg of glycoalkaloids per kg body weight and day.
The glycoalkaloid content in table potatoes should be no higher than 100 mg per kg fresh weight.
Properly cultivated, harvested and stored potatoes usually have a glycoalkaloid content of 20 to 100 mg per kg but examinations have occasionally shown levels of over 200 mg per kg of potatoes.
Previous cases and symptoms
BfR said only a few cases have been documented in the last 100 years but poisonings may go unreported due to the non-specific symptoms.
The most recent data for Germany from Bundesamt für Verbraucherschutz und Lebensmittelsicherheit (BVL) food monitoring in 2005 found only one (271 mg per kg) of 222 potato samples had a glycoalkaloid content above 200 mg per kg.
In Canada in 1984, 61 cases of poisoning among schoolchildren and the workforce of a school were reported after eating baked potatoes with a glycoalkaloid content of about 500 mg per kg.
Consumption of green, sprouting or damaged potatoes can lead to poisoning.
Consumers can perceive a bitter taste and a burning sensation in the mouth. Cases of minor poisoning cause symptoms such as nausea, stomach-ache, vomiting and diarrhoea, sometimes accompanied by fever.
In severe cases, which are rare, loss of consciousness can occur, along with disturbances in brain function, breathing and impact on the cardiovascular system.