Everyone knows them and just about everyone eats them, because they come in countless forms: the potato. But now the super tuber has been named the poisonous plant of the year 2022. The poisonous plant of the year is chosen every year by the special botanical garden in Hamburg-Wandsbek.
What many people don’t know is that potatoes can develop toxins. It is supposed to scare off predators in nature. If the potato receives too much light, it carries out photosynthesis and forms chlorophyll. This causes green spots to appear on the tuber. Because solanine is formed in the skin, the germination site and the tuber. This belongs to the toxic alkaloids and can lead to gastrointestinal complaints, headaches, shortness of breath and other symptoms if consumed.
Trick against green spots on potatoes
Potato farmer Heiner Vinnemann from Olfen also knows this. He has a large potato warehouse and the potatoes that are not uniform get his bulls. Green potatoes, however, are scarce. However, this is by no means a matter of luck, because the farmer has a trick so that the green spots do not form in the first place.
"We started using green light in our potato warehouse a few years ago," he says in an interview with the editorial team. This inhibits the production of solanine, because less photosynthesis is carried out by the potato due to the green light, and thus no more green spots are formed. And indeed, to find two small potatoes that still had slightly greenish spots, the farmer had to search quite hard in the warehouse. "As an alternative to the green light, you can just close the doors so it’s dark in the warehouse," Vinnemann said.
Optimal humidity is above 80 percent
So if you like your potatoes at home yellow, and not poisonous, you should store the tubers as dark and cool as possible. "But with a high humidity," adds the Olfen farmer. Optimal humidity for potatoes is over 80 percent. Only it must not be too high, then they can mold like all other foods.
The potatoes in Heiner Vinnemann’s large hall also enjoy a high level of humidity, with a system drawing in extra outside air for this purpose. "It ensures that they do not age so quickly and stay fresh for a long time," says Heiner Vinnemann. Potatoes with short and white shoots are also still edible, only with the long green shoots, one should throw away the tubers.
Potatoes often already green in the supermarket
If there are only small green spots on the tuber, they can be removed by cutting them away generously. Proceed in the same way if only small sprouts have formed. It is important to know that solanine is not destroyed by a normal cooking process, but only at temperatures above 240 degrees Celsius. Solanine content is lowest in predominantly large potatoes and newer varieties in relation to surface area. If your potato dish tastes strangely bitter, you should definitely not continue eating it.
Already in the supermarket you can make sure to buy potatoes without green spots. "But in the supermarkets, the potatoes are always under white LED light, when green light would be much better," says Heiner Vinnemann. "That’s something food retailers should think about," Vinnemann continued.