What can't be a brain teaser?

You can't eat anything harmful to your health.

Usually raw and poisonous things. You can't eat anything that will cause physical damage and adverse side effects.

Germinated and blue potatoes are poisonous and can't be eaten. Fresh day lily (day lily) is poisonous and can't be eaten. Green beans and lentils that have not been fried thoroughly are poisonous and should not be eaten. The head of an old chicken (the head of a chicken more than 5 years old) is poisonous and unfit to eat. Stir-fried pork liver contains toxins and is not suitable for eating. Preserved eggs and popcorn contain a lot of lead and are not suitable for children. Burned food can't be eaten, and it is easy to get cancer. Rotten ginger is extremely toxic, which can cause liver cell necrosis and must not be eaten. Raw soybean oil contains benzene, which will destroy the hematopoietic system and is not suitable for consumption. Long-term boiling water contains nitrite, which is easy to cause cancer. Too hot food can't be eaten, and it is easy to burn the digestive tract and cause cancer. Immature soybean milk can't be eaten and is easy to be poisoned. Pickled food contains carcinogens and should not be eaten more. Kebabs and fish fillets contain carcinogens and should not be eaten more. Persimmon air service is easy to suffer from persimmon stones in the stomach, so don't eat them. Food additives, artificial vegetarianism, spices, essences, preserved eggs, instant noodles, lunch meat, fried foods, etc. are not edible.