Not wasting food is a virtue, and many people are used to saving leftover dinner for the next day. However, some foods, if consumed overnight, may pose health hazards.
Overnight Tremella Fungus
Tremella soup is a high-nutritional health supplement, but its nutritional value decreases and harmful substances are produced after being left overnight.
This is because both cultivated and wild tremella fungus contain high levels of nitrates. When left for a long time after cooking, bacteria will break down the nitrates, reducing them to nitrites.
Nitrites oxidize the body's normal hemoglobin into methemoglobin, causing it to lose its ability to carry oxygen and resulting in a deficiency of normal blood-forming function.
Overnight Tea
Due to the long time it has been left, overnight tea has most of its vitamins depleted. Moreover, proteins and sugars in the tea become nutrients for bacteria and mold to grow, which is why it is generally considered undrinkable.
Overnight Eggs
If an egg is not fully cooked, eating the uncooked yolk overnight, especially if stored improperly, can easily lead to bacterial growth, causing gastrointestinal discomfort, bloating, etc. However, if the egg is fully cooked and properly sealed and stored at a low temperature, it is generally fine.
Tea eggs are typically boiled twice; the first time to cook them through, and the second time after cracking the shells and adding tea and other ingredients, so they are definitely fully cooked. However, semi-cooked eggs with a runny yolk should not be eaten overnight.
Overnight Leafy Green Vegetables
Some leafy green vegetables contain high levels of nitrates. When left for a long time after cooking, bacteria break down the nitrates into nitrites, which are carcinogenic and cannot be removed by reheating. Therefore, if you plan to cook extra food to reheat the next day, you should try to cook fewer stem and leaf vegetables and choose gourds instead.
In addition, all seafood and fish are not suitable for overnight consumption. Fish and seafood can easily produce protein degradation products overnight, which can damage liver and kidney function.