A lady called who just bought a bag of potatoes from a grocery store. Every potato in the bag is green under the skin. Even when you cut the potato in half you can see green roots. She should not eat the potatoes. She has the option of throwing them out or returning them to the store for a refund.
Many plants contain small amounts of naturally occurring toxic chemicals.
For example, two commonly eaten foods, the potato and the tomato, come from the nightshade family. The nightshade family is known to contain toxic compounds called alkaloids. The alkaloid in the potato is solanine. In the United States, healthy potatoes contain 1 to 5 milligrams of solanine per small potato. Solanine is produced as the potato gets old or is exposed to light.