Green food is a general term for non-polluting, safe and high-quality nutritious food. Green food originated in China in the early 1990s. Its development is based on the sustainable use of resources and environment. Starting from improving the agricultural ecological environment, it realizes the integrated quality management of pre-production, mid-production and post-production of agriculture to improve agricultural products. Quality and added value. The development of green food can not only meet the growing material needs of the people, but also an important symbol of agriculture's progress towards modernization. It is an important part of China's agricultural product quality and safety certification system. In order to ensure the specific quality of green food without pollution, safety and quality, in the production process of green food, it is required to implement the quality control of the whole process from the land to the table, and strictly limit the use of chemical substances in the production process. Therefore, it is especially important to analyze the main pollution factors and ways of green food production process and to formulate corresponding control measures to ensure the quality of green food products. 1 Definition and connotation of green food Green food refers to non-polluting safe, high-quality and nutritious foods that are produced according to the principle of sustainable development and produced according to specific production methods and approved by specialized agencies. Green foods are classified into AA grade and A grade 2, and AA grade green foods are prohibited from using any chemical synthetic substances in production, which is equivalent to organic foods. A limited amount of chemically synthesized substances are allowed in the production of Class A green foods. 2 Main pollution factors, pollution pathways and control measures in the production process of green food In the production process of green food, pollution mainly comes from four aspects: First, industrial waste pollutes farmland, water source and atmosphere, causing pollution of green food raw material producing areas, which leads to accumulation of harmful substances in crops; second, with agricultural production The use of chemical fertilizers, chemical pesticides and other chemical products has increased, some harmful chemical substances have been absorbed into agricultural products through the absorption of crops; the third is secondary pollution of airborne bacteria in food production and processing, secondary cross infection of hand bacteria, some The improper use of chemical pigments and chemical additives increases the harmful substances in foods; the fourth is microbial contamination caused by improper storage and processing. Among them, the first step in the production of green food is the production and cultivation of crops. The pollution in this link is the key to the final product not meeting the green food standards. 2.1 Main pollution routes In the production and cultivation of crops, the main sources of pollution are pesticides, heavy metals, nitrates, and harmful microorganisms. The main ways of pollution are: 1 Seed treatment: including pollution caused by seed cleaning, disinfection, coating and other processing links. 2 Fertilization medication: In the process of crop cultivation, due to improper use, type, and dosage, pesticides (such as insecticides, fungicides, herbicides) and chemical fertilizers are used for pollution. 3 Irrigation: The irrigation water for crops is polluted by industrial wastewater and domestic sewage, mainly heavy metals (mercury, lead, cadmium, copper, arsenic) and organic benzene. 2.2 Control measures for major pollution 1 Choose the appropriate place of production. The ecological environment conditions of the place of production are one of the main factors affecting green food products. At the beginning of the development of green food products, in-depth investigation of the environmental quality status (including soil, water quality and atmosphere) around the production area should be conducted to provide a scientific decision-making basis for the establishment of green food production areas. The green food producing areas should choose to avoid the bustling cities, industrial areas and traffic routes in areas with fresh air, pure water, uncontaminated soil and good agricultural ecological environment. The specific requirements are: there should be no air pollution sources around the place of origin and production areas, especially the upper air outlets must not have pollution sources, such as chemical plants, cement plants, garbage dumps, industrial and mining waste slag yards, etc., and there should be no toxic gas emissions and soot and dust. Production water should not contain pollutants, especially heavy metals and toxic and hazardous substances. It is necessary to choose clean and pollution-free areas of surface water and groundwater, and away from factory mines that are prone to water pollution. For the requirements of the soil, the production area should be located in the area where the soil background value is normal, there is no metal or non-metallic mine around, and there is no pesticide residue in the soil. At the same time, soil fertility indicators should be considered, and areas with high soil organic matter content should be selected. For areas where the natural background value of certain elements in the soil is high (such as radioactive elements, high background areas of heavy metal elements), such elements can not be used as green food producing areas because they can accumulate through plants and harm humans through the food chain. 2 Select crop varieties that are resistant to pests and diseases and have strong resistance. Due to the specific standards and production regulations of green foods, the application of fertilizers and pesticides must be limited in production. Therefore, when selecting crop varieties to take into account high-yield and high-quality traits, attention should be paid to the selection of varieties resistant to pests, diseases, and high light efficiency to reduce or avoid the occurrence of pests and diseases, thereby reducing the application and pollution of pesticides. When introducing seeds, the characteristics of the varieties should be considered in connection with the cultivation conditions. For example, vegetables have strong enrichment ability for various heavy metals, and more pesticides and fertilizers are generally applied in the production process. Coupled with the short growth cycle of vegetables, pesticide residues, nitrate accumulation and heavy metal pollution and other harmful substances in their products pose a greater threat to human health, such as 80% of the nitrates ingested by the human body. Vegetables, therefore, it is necessary to select suitable soil conditions for production according to the rich ability of different vegetable varieties for heavy metals and nitrates. For example, spinach, Chinese cabbage and other leafy vegetables with strong ability to enrich heavy metals should be planted in areas with high fertility to reduce the input of fertilizer. 3 Apply organic fertilizer, less prudent application of chemical fertilizer. Green food production requires organic fertilizers to minimize or eliminate chemical fertilizers. Organic fertilizer is a total nutrient fertilizer, which not only has long fertilizer efficiency, but also increases the organic matter of the soil and improves soil fertility. Organic fertilizers generally include manure, manure, compost, green manure, biogas fertilizer, cake fertilizer, crop straw and other farmyard manure, as well as humic acid fertilizers and microbial fertilizers. When making and using organic fertilizers, pay attention to the harmless treatment, such as high temperature reactor, biogas fermentation, etc. In the production of green food, try to control and reduce the use of chemical fertilizers, especially nitrogen fertilizers. In addition to the use of trace elements and potassium sulfate, calcined phosphate, AA grade green food production does not allow the use of other chemical synthetic fertilizers. In the production of A-grade green food, a limited amount of chemical synthetic fertilizer is allowed, but the use of nitrate nitrogen fertilizer is prohibited. When chemical fertilizers must be used, they should be used in combination with organic fertilizers in a nitrogen ratio of 1:1, and the final use time must be applied 30 days before crop harvesting. 4 Promote integrated prevention and control of pests and diseases. In the production of green food, comprehensive prevention and control is of great significance. "Integrated prevention and control" is based on agro-ecology as a theoretical basis. Starting from the overall situation of agricultural production, comprehensive use of various control measures to create an ecological environment that inhibits the breeding of pests and diseases, is conducive to crop growth and the proliferation of various natural enemies, and maintains agro-ecology. The balance of the system. The main prevention measures are as follows: Agricultural measures: By selecting excellent varieties resistant to pests and diseases, rational crop layout, clean field, rational rotation, intercropping, timely weeding and weeding, deep ploughing, etc., can effectively reduce the occurrence of pests and diseases. Physical and artificial control. Use physical factors or mechanical, artificial and other measures to control pests and diseases, such as artificial capture, light color trapping, mechanical weeding, artificial weeding, and high frequency electricity, microwave, laser and so on. Biological control: generally refers to the method of controlling the number of harmful organisms by beneficial organisms, that is, using natural enemies to control pests and diseases. Chemical control: In the production of green foods, pesticides should be used to control pests and diseases, and pesticides of biological and mineral sources should be preferred. When the above methods are not enough to control pests and diseases, high-efficiency, low-toxic, low-residue chemical pesticides can be used. In general, the relevant provisions of the Guidelines for the Use of Pesticides for Producing Green Foods should be followed. It is strictly forbidden to use highly toxic, highly toxic, high-residue or tri-toxic (carcinogenic, teratogenic, mutagenic) pesticides, and strictly control the application rate and safety interval according to the requirements of national standards. 3 Main pollution pathways and control measures in the processing of green food products In the process of food processing, from raw materials into finished products to finished products, it can be generally divided into three main links: raw materials and auxiliary materials processing, production processing and product packaging. Contamination of raw materials, use of additives, improper production processes, poor hygiene, and contamination of machinery and equipment may cause contamination of the final product. Therefore, every step and process of processing must be strictly controlled to prevent secondary pollution during the processing. 3.1 Main pollution pathways in the processing of green food products 3.1.1 Contamination of raw materials Raw materials for green food processing, including agricultural and forestry products, livestock and poultry products, aquatic products and processing water, etc., may result in the enrichment or residue of pesticides and heavy metals caused by harmful substances, pathogenic microorganisms or raw materials due to improper production and storage. The product does not meet the green food standard. For example, the grain product produces aflatoxin due to mildew during storage and transportation; the juice product uses the spoiled fruit raw material to make juice, and the mold causes the fruit juice to produce bacillus toxin. 3.1.2 Pollution of the geographical environment and plant of the production enterprise The pollution sources around the site environment of the production enterprise, such as the site located in heavy industrial areas or residential areas, may cause pollution to the production of the products. The scientific and reasonable layout of the company's workshop layout, supply and discharge system, sanitary conditions and management system are also important factors to ensure production is free from pollution. 3.1.3 Secondary pollution control of hand bacteria According to the research results of Shanghai Kangjiu Environmental Protection Technology Co., Ltd., which specializes in food sterilization technology research and development and equipment manufacturing, hand disinfection is a simple and negligible link, which is basically ignored. There are many opportunities for bacteria, viruses, and dirt to come into contact with the outside world, and it is easy to be soiled. There are about 800,000 bacteria in a pair of unwashed hands. At present, most enterprises have defects in hand disinfection methods. They are soaked and disinfected with peroxide disinfectant or chlorine-containing disinfectant. It is necessary to continue to soak for 3 minutes to achieve the expected sterilization effect, but the staff are concentrated at work, mostly It can symbolically share a basin of disinfection and water immersion. The disinfection time is not guaranteed, and many people use it repeatedly. Eventually, the concentration of disinfection water is not enough to become a source of pollution. After washing hands, use a common towel to wipe hands. The pollution is more serious. It can be described as a thousand miles. The embankment was destroyed by the ant colony. It is recommended to install NCL-Q8 automatic sensor hand sterilizer. For example, 75% medical alcohol is used as the disinfection medium process: “Induction soap machine washing hand – faucet washing – Inductive drying – Inductive hand disinfectionâ€; Other disinfectant is used as disinfection The medium flow is: “Induction of soap machine washing hands – faucet washing – inductive hand disinfection – inductive dryingâ€; it is recommended to choose the first method, because there is no residue in the hands after the alcohol is volatilized. 3.1.4 Pollution caused by production processes and equipment In the processing of green food products, attention must be paid to the continuity and rationality of the process. If the production process is out of line or the interval between processes is too long, the exposure of raw materials, semi-finished products and finished products to the air for a long time will increase the chance of pollution; If the production equipment is backward or unsuitable for the process technology, it will not reach the effective temperature, time, etc., or the process technology is unreasonable, it will cause pollution to the product; if the process of leaching vegetable oil by organic solvent, the residual amount of solvent or solvent The toxic substances such as polycyclic aromatic hydrocarbons exceed the hygienic standard; the processing equipment uses copper, lead, zinc, ceramics and other materials, which are easily contaminated by the dissolution of lead and arsenic under acid, alkali, high temperature and high pressure conditions. 3.1.5 Contamination caused by improper use of chemical synthesis additives Food additives are chemically synthesized or natural substances added to foods to improve the color, aroma, taste, shape, nutritional value of foods and the need for preservation and processing. Green food processing focuses on the safety of additives. The additives mainly include preservatives, antioxidants, enzyme preparations, nutritional supplements, flavoring agents, coloring agents, and the like. For example, if alum is added as a thickener and stabilizer in the production of fans, preservatives such as sodium benzoate and nitrite are used in food processing because of their chronic toxicity or "three-way (carcinogenic, teratogenic, mutagenic) effects. "Does not meet the requirements of the green food standard. 3.1.6 Contamination caused by improper packaging of products In the food packaging process, because the packaging technology and packaging materials can not meet the requirements of the processing technology, such as poor sterilization technology, insufficient packaging barrier and sealing, the microbes in the food exceed the standard, or the packaging materials contain toxic substances, such as packaging patterns. Polychlorinated biphenyls that may be contained in the ink are easily absorbed by foods such as fats and oils; lead in ceramic containers, and chloroolefin monomers in polyvinyl chloride plastic packaging may also cause pollution to food. 3.2 Control measures for major pollution in green food processing The processing of green food products should adopt advanced scientific techniques to maximize the preservation of the natural properties, nutrition and original flavor of the food, and avoid secondary pollution during processing. 3.2.1 Strict testing of raw and auxiliary materials, strict management of production process Green food processing raw materials should first have food-grade quality. The main raw materials must come from the raw material base certified by green food. The auxiliary materials such as salt and sugar should have a fixed supply source, and a report issued by the authority according to the green food standard inspection will be issued. As a common raw material in processing, processing water must be tested to meet the sanitary standards of drinking water in China. Fresh, clean, mildew-free, non-toxic substances (such as pesticides and heavy metal residues), high-quality raw materials, especially fruits and vegetables should be used. Only when they are fresh, have the highest vitamin content and the best nutritional flavor, so as to ensure processing. Good quality food. Green food manufacturers should strictly follow the design requirements of food factories, scientifically and rationally select the site, design workshop warehouse and other facilities, strictly manage the sanitary management of the processing process, avoid environmental pollution to production and secondary pollution of product processing. 3.2.2 Adopt advanced processing technology and equipment Green food processing must be based on its own characteristics, using appropriate new technologies, new processes and advanced equipment to improve the quality of green food. The use of advanced processes and equipment can control pollution from two aspects: First, to ensure the continuity of the processing. The various processes in the production process are compact and reasonable, which can shorten the processing cycle, avoid secondary pollution and loss of nutrients in food; in the cooling, inner packaging and filling areas, purchase food dynamic disinfection equipment, this equipment is harmless to the human body, In the case of people working, the bacteria in the air environment are simultaneously killed to avoid secondary pollution. Shanghai Kangjiu Environmental Protection Technology Co., Ltd. is the sole manufacturer of this equipment. The second is to strictly control the production process parameters. Advanced process technology usually sets the scientific processing time, temperature, speed and pH parameters under the premise of maximally retaining the nutritional content of food, which is beneficial to reduce pollution and improve product quality and hygiene. The advanced technologies that can be used in green food processing are: biotechnology, such as enzyme engineering, fermentation engineering; membrane separation technology; freeze drying technology; hand sterilization technology; vacuum processing technology; aseptic packaging technology; air dynamic disinfection technology; Extraction technology; low temperature concentration technology and so on. For example, the "NICOLER food dynamic disinfection machine" can solve the problem of secondary pollution of bacteria in the cooling, inner packaging and filling workshops. The use of physical sterilization and aseptic packaging in the production of fruit juice beverages can reduce the damage to nutrients and achieve the purpose of no preservatives and no pollution. With the continuous development of science and technology, green food processing can use computer control technology to make the food processing process more specialized, intensive, continuous and automated, to better control the production process and reduce pollution. However, the advanced technology must conform to the processing principle of green food. For example, green food is strictly prohibited from genetic engineering technology, and it is strictly forbidden to use radiation or microwave processing. 3.2.3 Reasonable use of food additives The use of additives in green food processing is a key to the ability of products to meet green food standards. When processing green foods, enzyme preparations, nutritional supplements, etc. generally meet national standards, while preservatives, antioxidants, pigments, and flavors are very strict. If additives must be used in processing, the appropriate types and dosages must be selected in strict accordance with the Guidelines for the Use of Green Food Additives. AA grade green foods are prohibited from using any chemically synthesized food additives in production. Grade A green foods are only allowed in production. Limited use of limited chemical synthetic food additives, the maximum allowable use is 60% of the maximum use of ordinary foods, because the maximum use of food additives in the GB2760-1996 standard is the upper limit without side effects, as long as it is achieved in actual production. The effect is sufficient. Therefore, the maximum use amount of chemical synthetic additives in the A-grade green food is reduced to a large extent, reflecting the safety of the green food.