First, the definition of poison, under the condition of daily contact, a small dose of chemical substances can interact with organisms chemically or physico-chemically, resulting in damage to the metabolism, function and morphological structure of tissues and cells in the body.
1. In medicine, substances that are formed in organisms (including animals, plants, bacteria and fungi, etc.) and can damage other organisms are called biotoxins, which are called toxins for short.
2. Chemical poisons synthesized artificially.
These two kinds of substances belong to the category of big poisons. There is no absolute boundary between poison and non-poison.
There is a famous saying: "All substances are poisons, nothing is not poisons, the only difference is their dosage".
In a sense, there are no absolutely toxic or nontoxic substances in nature, such as arsenic, mercuric compounds, snake venom, etc. As we all know, poisons can be used as drugs for clinical treatment of some diseases if they are used below the toxic dose. However, if the oxygen we depend on enters the body at a high concentration than normal, oxygen poisoning will also occur.
Second, the ability of poisons to cause damage to the body is called toxicity.
What we usually see as "highly toxic" and "low toxic" actually refers to the toxicity of poisons. According to the WHO acute toxicity classification standard, the toxicity classification of poisons is as follows:
1, highly toxic: toxicity grade 5; Adult lethal dose, less than 0.05g/kg body weight; Total lethal dose of 60 kg adults, 0. 1 g.
2. High toxicity: the toxicity grade is 4; Adult lethal dose, 0.05 ~ 0.5g/kg body weight; 60 kg adult lethal total, 3 grams.
3. Moderate toxicity: toxicity grade 3; Adult lethal dose, 0.5 ~ 5g/kg body weight; Total lethal dose of 60 kg adults, 30 g.
4. Low toxicity: toxicity grade 2; Adult lethal dose, 5 ~15g/kg body weight; Total lethal dose of 60 kg adults, 250 g.
5. Slight toxicity: toxicity classification 1 grade; Adult lethal dose, greater than15g/kg body weight; The total lethal dose of 60kg adults is greater than1000g.
Therefore, whether food is toxic or not depends mainly on the amount of toxins and toxicants in it, which requires advanced instruments to accurately detect. Even if we detect the amount, we don't know his ability to hurt an individual, because everyone's physique is different and their resistance is different.