Biological or chemical substances originally added or artificially added to foods that have acute or chronic hazards to human health is the so called food contamination.
Classification of food contamination
- According to the nature of the source, food contaminationis divided into biological contamination, chemical contaminationand radioactive contamination.
(1) Biological contamination of food includes microorganisms, parasites and insects, toxic biological tissues, and insects. The main contamination is microbial contamination, which is more harmful, especially bacteria and bacterial toxins, mold and mold toxin.
(2) The source of chemical contamination is complex and various. For example, ① Pollutants from production, life and environment, such as pesticides, harmful metals, polycyclic aromatic hydrocarbon compounds, N-nitroso compounds, dioxins, etc. ② From the production, processing, transportation, storage and sales of tools, containers, packaging materials and coatings and other materials into the food materials, monomers and additives and other substances. ③ Substances generated during food processing and storage, such as harmful alcohols and aldehydes in alcohol. ④ Abuse of food additives.
(3) Radioactive contamination: the man-made radionuclide contamination in the environment mainly comes from the following aspects: nuclear explosion, discharge of nuclear waste, accidents. Radionuclides in the environment can be transferred to food through the food chain. The main transfer pathways are: transfer to aquatic organisms, to plants, and to animals. Harm to human body caused by radioactive contamination of food include long-term irradiation effects of low-dose radiation on various tissues, organs and cells in the human body after ingestion of contaminated food. It shows damage to the immune system and reproductive system, as well as carcinogenic, teratogenic and mutagenic effects.
- According to the way of food contamination, it is classifiedas:
1). Endogenous contamination
(1) Endogenous contamination
(2) Endogenous biological contamination: Livestock and poultry are infected with zoonotic diseases (meat, eggs, and milk are contaminated); Livestock and poultry are infected with inherent diseases, and their resistance decreases to cause secondary infections. During the life of livestock and poultry, some microorganisms are contaminated, and the decline in the resistance of livestock and poultry causes these microorganisms to infiltrate into muscle, liver and other parts, causing meat contamination.
(3) Endogenous chemical contamination
(4) Endogenous radioactive contamination
2). Exogenous contamination
Exogenous biological contamination: food processing, transportation, storage, sales, cooking and other processes due to non-compliance with operating procedures, resulting in contamination by microorganisms, etc. (1) through water contamination (2) through air contamination (3) Contamination through soil (4) Contamination during production and processing (5) Contamination during transportation / storage (6) Contamination by vector pests
Exogenous chemical contamination: Food is contaminated by toxic chemicals during processing, transportation, storage, sales, cooking, etc. The affected link include: (1) air (2) water (3) soil 4) transportation (5) production and processing
Characteristics of food contamination
Food is becoming more and more contaminated, and chemical contamination is the main cause.
When pollutants are transferred from one organism to another, the concentration can be continuously accumulated and increased, which is the so-called bio-accumulation effect, and even the slight contamination process can cause serious harm to the human body after bio-accumulation.
The hazards caused by food contamination today are more common than chronic toxicity, in addition to acute toxicity. Due to a small amount of human exposure for a long time and a long biological half-life, food contaminants have played a role in DNA in the body.
The harm of food contamination to the human body
- Affect the sensory characteristics of food;
- Cause acute food poisoning;
- Cause acute and chronic hazards to the body;
- Teratogenic, mutagenic and carcinogenic effects on humans.
- The hazards of biological contamination: cause animal food corruption and deterioration; human infectious diseases; microbial poisoning.
- Harm of chemical contamination: acute, chronic poisoning; mutagenicity; teratogenic and carcinogenic.