Food Inspection and Food Safety Name: Name: Lu Xuehao: Student ID: 432084 19 Score: Abstract: As China is in the primary stage of socialism, the productivity level of food-related industries in China is far from developed Abstract: The national level, and food enterprises are not honest (especially private enterprises), with low food consumption value and poor safety awareness. For various reasons, food safety control has become a top priority. Mainly for food additives, toxins, harmful microorganisms and other ingredients that are harmful to human health or may be crucial to food testing. With the progress of science and technology, food testing will face more opportunities and challenges in the future. Key words: food safety, food detection, additives, toxins, pesticide residues, microorganisms, gene chip, immunological technology, instrumental analysis. There is no doubt that food is the most important thing for people. Food safety is related to everyone's health and affects the stable development and continuous progress of society. If food safety cannot be properly controlled, it will inevitably lead to serious personal safety accidents and social disorder, which will eventually affect the status and image of the ruling party and hinder the rapid development of social economy. It is imperative to implement high-quality food inspection and testing with high technology! 1 overview of food safety issues in China under the current situation, China has promulgated the Food Hygiene Law and the Agricultural Products Quality Safety Law to regulate food safety-related issues, and established food safety management regulations for governments at all levels in provinces, cities and regions. Since 20 10, the food safety situation in China has improved significantly compared with the past. In the first half of 20 10, the qualified rate was over 90%, which kept the high qualified rate of imported and exported food. However, because China is in the primary stage of socialism, the productivity level of food-related industries in China is far from that of developed countries, and food enterprises have a weak sense of integrity (especially private enterprises), a low level of food consumption value and a poor sense of safety. The food safety problem in China is still very serious due to various reasons, specifically: 1) The phenomenon of microbial contamination from food sources is serious. There is no doubt that the related diseases caused by pathogenic microorganisms are the primary problems facing food safety at present. As far as China is concerned, most food poisoning is caused by pathogenic microorganisms. The common pathogenic microorganisms in China are Salmonella, Enterohemorrhagic Escherichia coli and Listeria monocytogenes. Microbial contamination of food sources is increasing every year. 2) Fertilization and pesticides lead to food safety problems. There is no doubt that China is a big agricultural country. In the process of planting rice, wheat and vegetables, a large number of fertilizers, pesticides and growth regulators are used, which often pollute food at the source. Large-scale and large-dose use of chemical fertilizers and pesticides will lead to an increase in nitrate accumulation in food. Nitrite is the most important carcinogen in food published by the World Health Organization, and it does great harm to human body. At present, pesticide residues are also an important factor in food safety, and organic vegetables are the hottest topic at present. 3) Due to the lack of legal awareness and conscience of producers and operators, the problem of counterfeiting in food production and processing is prominent. 4) Abuse of food additives. In the process of food processing, it is inevitable to add various additives to meet the taste requirements of different people. However, illegal processing institutions randomly add preservatives, pigments and various chemical preservation substances, which leads to a great increase in food safety hazards, such as the melamine milk powder case and the gutter oil case reported by the media [1]. 1. 1 Food safety incidents frequently coexist with responsibilities and opportunities, and all links in the food industry chain attach great importance to safety and quality issues, including how to strengthen enterprises' own food safety awareness and moral concepts. With the promulgation and implementation of the Food Safety Law of People's Republic of China (PRC), the importance of food safety in the management of the food industry is increasingly apparent, which has aroused widespread concern from all walks of life. Food safety has become a hot topic in today's society. The level of food safety and quality inspection is an important link and technical support for establishing and perfecting China's food safety guarantee system. Food safety has attracted more and more attention from the whole people. Whether it is domestic food or imported food, there should be a set of operational testing and monitoring procedures. Especially when there is a problem with a certain food, the functional departments should immediately intervene in the investigation and produce convincing test results and evaluation reports with a scientific and fair attitude. This protects the interests of businesses and consumers. 1.2 Exposing loopholes in domestic food testing. Food testing is the last pass to enter and exit the market, but it may exist in name only or in name only in some places, exposing the existence of "short legs" in food testing. Many enterprises in China have poor detection ability, low detection sensitivity and backward detection technology. Food safety problems mainly focus on traditional detection items such as excessive microorganisms, excessive residues of agricultural and veterinary drugs, excessive food additives, excessive toxic and harmful substances, and detection of harmful organisms. Vulnerabilities in food safety supervision need to be prevented urgently. At present, although China has established a food supervision system composed of quality inspection, industry and commerce, food and drug supervision, medical and health departments, the working systems of the above departments have been stylized to some extent, and it is difficult to find problems by notifying in advance or letting merchants take the initiative to send them for inspection before inspection. It is reported that the current food safety supervision system implements subsection supervision, involving agriculture, forestry, fishery, quality supervision, industry and commerce, health, food and medicine, entry-exit inspection and quarantine and other departments. Food inspection institutions are scattered, low-level redundant construction and repeated testing, and testing information cannot be shared. Therefore, the integration of "testing plan, testing funds, testing information and testing ability" has become the top priority of food safety work, but there is no ready-made experience for reference. 1.3 food safety control has become a top priority. With the development of economy, chemical fertilizers, pesticides and veterinary drugs are widely used in agricultural production. The earth's ecological environment is being destroyed like never before, and the food quality and safety are threatened, which in turn threatens human health and safety? In addition, the application of chemical additives and transgenic technology has also increased people's concerns about food safety. Therefore, food safety control has become a top priority. Food safety involves the key detection technology and laboratory detection ability of food-borne hazards. There are two obvious trends in food safety and hygiene control in developed countries: first, the limited value of safety and hygiene indicators is gradually decreasing; Second, the detection technology tends to be high-tech, serialized, fast and portable. Therefore, in China's 11th Five-Year Plan, improving the self-inspection and self-control ability of enterprises, strictly implementing the food safety market access system of food production enterprises, starting with the necessary conditions for enterprises to ensure the quality and safety of "vegetable basket" products, and adopting supervision measures such as production license and factory compulsory inspection are listed as one of the development goals? In promoting food export, we should supervise the whole process from farms, planting bases and other producing areas to export departure, help and urge export production enterprises to produce and manage according to the requirements of importing countries, and ensure the quality of export products. For imported food, it is necessary to use food safety control techniques and methods, increase testing efforts, ensure that imported food meets national safety and health requirements, greatly improve China's food quality and safety guarantee system, and comprehensively improve the quality level of China's food industry. 2 main contents of food testing 2. 1 detection of food additives food additives refer to chemical substances or natural substances added to food to improve the quality, color, aroma and taste of food and meet the needs of preservation and processing technology. At present, there are 14000 kinds of food additives found all over the world. By the end of 1999, there were l587 kinds of food additives allowed in China. Food additives are the basic raw materials of food industry, which play a vital role in food production technology, product quality, safety and hygiene. However, illegal use, abuse and excessive use of additives will bring great harm to food quality, safety and health and the health of consumers. There are more and more kinds and quantities of food additives, which have more and more influence on people's health. With the continuous improvement and development of research, it has been found in recent years that additives that were originally considered harmless may still have various potential hazards such as slow toxicity, carcinogenicity, teratogenicity and mutagenicity, which cannot be ignored. Food processing enterprises must strictly abide by the hygiene standards of food additives, strengthen hygiene management, standardize, rationally and safely use additives, ensure food quality and protect people's health. The analysis and detection of food additives have played a very good role in supervising, ensuring and promoting food safety. For example, nitrate and nitrite are the most commonly used color developers in meat production. Under the action of microorganisms, nitrate is reduced to nitrite, which is produced by lactic acid in muscle. Nitrite is extremely unstable and can be decomposed into nitroso, which combines with myoglobin in muscle tissue to produce bright red nitroso myoglobin, which makes meat products show good color. But nitrite is the precursor of nitrosamine, which is a carcinogen, so accessory pigments such as sodium ascorbate or sodium ascorbate and nicotinamide is often used in processing to reduce the amount of nitrite used in meat products. China's "Hygienic Standard for Food Addition" (GB 2760- 1996) stipulates that the maximum dosage of nitrite in pickled meat, canned meat and meat products is 0. 15g/kg, the maximum dosage of sodium nitrate is 0.5g/kg, and the residue (calculated by sodium nitrite) in canned meat and meat products should not exceed 0.05g/kg. Nitrite can be determined by naphthyl ethylenediamine hydrochloride method. Nitrate can be precipitated by protein. After the fat is removed, the sample extract passes through a cadmium column to reduce nitrate ions into nitrite ions. 2.2 Properties and detection methods of common toxins and several typical toxins in food In daily life, we come into contact with foods produced by different companies and different places every day. But in recent years, food quality problems often appear in China. Five years ago, the industrial dye Sudan red was found in KFC's chicken wings. Subsequently, the problem salted egg was found to contain the industrial dye Sudan red. Illegal businessmen feed pigs with lean meat essence, so that the pork they eat contains lean meat essence harmful to human heart. Malachite green is used to raise fish in the market, which makes fish contain harmful substance malachite green. Melamine was illegally added to Sanlu milk powder last year. Food safety not only happens in China, but also often happens around us. In 2007, a serious food poisoning incident occurred in Zhuhai College of Jinan University, and many teachers and students were unwell. Students often get gastroenteritis because they eat unclean food. Unsafe food is also flooding the market. Therefore, people have to pay attention to food quality. Common toxins in food include mycotoxins, natural animal toxins and natural plant toxins. Among them, the common mycotoxins in food are aflatoxin, penicillin, Trichosporon, zearalenone, patulin, penicillin island and other mycotoxins. Common natural animal toxins include toxins in animal liver, tetrodotoxin, clam toxin, spirochete toxin and histamine. Common natural plant toxins include cyanosides, hemagglutinin, saponins, solanine, colchicine, gossypol and poisonous mushrooms. For example, aflatoxin is a Xie's product of Aspergillus flavus and Aspergillus parasiticus, which mainly exists in moldy peanuts, grains, nuts and rice, and aflatoxin is often contained in edible oil and other products. It is a group of compounds with similar chemical structure and the same toxic group produced by Aspergillus flavus and Aspergillus parasiticus. At present, 18 species have been isolated and identified, mainly aflatoxins B 1, B2, G 1, G2, and hydroxylated metabolites B 1 and B2 in vivo, such as B 1, M2, etc. B 1 is a derivative of dihydrofuran oxynaphthone, which contains a difuran ring and an oxynaphthone (coumarin). The former has an alkaline toxic structure, and the latter is related to carcinogenesis. The harm of aflatoxin to human health is mainly due to people eating food contaminated by aflatoxin. There are two ways, one is to ingest plant food contaminated by aflatoxin (mainly B 1), and the other is to enter aflatoxin (mainly M 1) in milk or dairy products (including cheese and milk powder) through feed. The lethal dose of aflatoxin B 1 is 0. 36 mg/ kg body weight, which belongs to the extremely toxic range (the lethal dose of animals is 10 mg/ kg, and its toxicity is 68 times greater than that of potassium cyanide 10 and arsenic). The poisoning caused by aflatoxin B 1 mainly damages the liver, leading to hepatitis and cirrhosis [Therefore, the detection method of aflatoxin is extremely important in food detection. The detection methods of aflatoxin B 1 at home and abroad mainly include thin layer chromatography, enzyme-linked immunosorbent assay, high performance liquid chromatography and fluorescence spectrophotometry. Aflatoxin B 1 in feed was purified by immunoaffinity column, and the fluorescence detection method of high performance liquid chromatography [6] was studied, which provided a simple and feasible method for monitoring aflatoxin B 1 in feed. 2.3 Harmful microorganisms in food In the modern food industry, there are many harmful microorganisms that seriously endanger the quality of food and people's health, and even cause some serious diseases. With the rapid development of economy, there is an increasing demand for various foods, and there are more and more food poisoning incidents caused by harmful microorganisms. The traditional detection methods, such as non-selective and selective enrichment, growth method, serological identification, etc., although accurate, are laborious and time-consuming, and generally take 4-7 days to complete. In addition, the low pollution level of pathogenic bacteria, the "harm" of bacteria after food processing and the interference of other food components all limit the traditional detection methods. Therefore, it is necessary to find pathogenic bacteria in time and control pollution and its possible harm to human health. With the development of molecular biology technology, many food workers can seek faster and more effective methods to detect pathogenic bacteria, so as to improve sensitivity and significantly reduce detection time. Among them, PCR is one of the most effective and widely used detection methods [7]. Analysis of the development direction of food safety testing With a case of smoking poisonous peppers and vermicelli with sulfur, processing meat stuffing with sick and dead pork, processing braised pork with poppy shells, and inferior milk powder causing big-headed dolls, melamine and Sudan red to be exposed by the media, one important question is before us: How to effectively strengthen food safety testing? What is the trend of food safety testing technology? In order to ensure food safety in China, the government initiated and implemented a series of major measures to build a food safety guarantee system: formulated a series of laws and regulations related to food safety, issued a series of national and industrial standards related to food safety, and initially established a food safety guarantee system in China with food safety testing technology and instruments as its technical support. 3. 1 Trend of gene chip detection technology Earlier, Anthony et al. established a method to quickly detect food safety performance by measuring the content of pathogenic microorganisms in a short time. After blood culture, 158 samples were tested, and its effective qualified rate reached 80%. Carl et al. introduced the gene detection method for four kinds of bacteria (Escherichia coli, Shigella dysenteriae, Salmonella typhi and Campylobacter jejuni), which greatly improved the detection accuracy, saved the detection time and had strong operability. The main method is to separate related pathogenic microorganisms or other microorganisms from water and food, and compare the characteristics of related bacteria with the standard strains of Salmonella, Shigella and Escherichia coli, so as to obtain the pathogenic factors of related microorganisms. Compared with conventional detection methods and PCR detection methods, gene chip detection technology can detect a wide range of bacteria, the qualified rate is 99%, and the detection time is greatly shortened. Generally speaking, the detection time of gene chip technology is four hours, while the traditional PCR technology takes eight hours. The development of gene chip detection technology has greatly changed the related concepts of food safety detection, especially the food safety detection before transgenic. Because from the current situation, the safety of genetically modified food is controversial, and there is no universal detection method at present, but gene chip detection technology can accurately detect genetically modified food. By analyzing the current general gene reports and various gene-specific fragments, we can make [8] chip samples, and then simply hybridize them with the detected food, so as to accurately judge the characteristic performance of genetically modified food. 3.2 Immunology technology Immunology technology uses the direct reaction between antigen and antibody, combined with immune related technologies to detect bacteria. The advantage of immunology technology is that bacteria can be directly selected without separation, and bacteria can be directly screened through immunization. Because there are many reactions between antigen and antibody, immunological methods are not uniform. At present, in food safety detection, immunomagnetic bead separation, immunoassay reagent strip, immunolatex reagent, immunoenzyme technology, immunodepth method or immunochromatography are often used. Immunoassay has very high accuracy, and the detected food can be detected in a short time after enrichment, and what is more prominent is that the reaction time between antigen and antibody is quite short. Immunomagnetic bead separation method can quickly collect and concentrate a large number of trace bacteria in food and analyze their harmfulness, which can effectively prevent food poisoning caused by TDH-positive Vibrio parahaemolyticus. Colloidal gold immunochromatography can accurately detect Salmonella, and immunochromatographic test strips can be effectively formed by placing antibodies to prevent the related harm of such bacteria, which provides a good prospect for the current food safety detection [9]. 3.3 Development trend of pesticide residue detection technology At present, most chromatographic pesticide residue detection adopts selective detectors: electron capture detector (ECD), nitrogen and phosphorus detector (NPD), flame photometric detector (FPD), fluorescence detector, mass spectrometry detector (MSD) and immune detector developed in recent years. ECD is mainly used to detect organochlorine, chrysanthemum and other halogen-containing pesticides with very high sensitivity. NPD is mainly used to detect organophosphorus and carbamate pesticides containing nitrogen and phosphorus. FPD mainly detects organophosphorus pesticides; Fluorescence detector is mainly used for derivatization detection of carbamate pesticides in liquid chromatography. In recent years, with the development of pesticide industry, the verification technology of pesticide residue detection needs to be re-recognized. MSD is the most commonly used technology for verification analysis and can also be used for quantitative analysis, but it is expensive and requires high technology. Since the appearance of capillary column, two-dimensional chromatography has developed rapidly. By using two different instruments or one instrument with two columns (different polarities), two channels and two detectors, two sets of information can be obtained simultaneously by one sampling. This method was first used for qualitative detection by FDA in the United States and European countries. This method is more suitable for the reality of China and has broad application prospects. Liu Changwu and others developed a two-dimensional chromatographic method for rapid detection of dozens of pesticides. The United States reported the qualitative and quantitative detection of hundreds of different types of pesticides in about 1h by using rapid scanning technology. Instrumental analysis technologies such as chromatography have higher requirements for detection technicians and instruments, but they can be used for qualitative and quantitative analysis of pesticide residues with high detection sensitivity, and can detect several or even hundreds of known and unknown pesticides, and provide scientific, accurate and fair detection data as arbitration basis. As a laboratory rapid detection technology, it can be combined with on-site rapid detection technology to give full play to their respective advantages and strengthen supervision and management. 3.4 Detection technology of genetically modified food There is no unified definition of genetically modified food at present. It can be understood as food containing or processed by genetically modified organisms. Genetically modified food can also be a mixture of many different genetically modified organisms and non-genetically modified organisms. At present, genetically modified foods mainly come from genetically modified plants. The safety of genetically modified products has always been the focus of attention of countries around the world and international organizations such as the United Nations. In 2000, the United Nations adopted the Biosafety Protocol, which was recognized by most countries in the world and came into effect. One of the most important measures in the Protocol is to test the genetically modified products to determine their types and whether they are approved or licensed, so as to prevent some risky genetically modified products from spreading at will and causing irreparable losses. Generally speaking, there are three detection methods for genetically modified foods: (1) nucleic acid detection method, including polymerase chain reaction (Fxj~PCR), ligase chain reaction (LCR, fingerprint RFLP, AFLP and RAPL, etc.) and probe hybridization method. (2) protein detection methods, including protein one-dimensional electrophoresis, protein two-dimensional electrophoresis, [1 1]western hybridization analysis and ELISAl(3) enzyme activity detection methods. Gene chip technology can solve the problem of detecting a large number of genes, and it is a more effective and faster detection method, especially for Qualcomm. Gene chip, also known as DNA microarray, refers to a segmented array of DNA formed by regularly arranging and fixing many specific oligonucleotide fragments or gene fragments on a support as a probe. After hybridization between the chip and the fluorescently labeled gene of the sample to be tested according to the principle of base pairing, the surface of the chip is scanned by a laser focused fluorescence detection system, and the sample information can be obtained. The detection chip of genetically modified products developed in China can basically be realized: determine whether it is a genetically modified product, what kind of genetically modified product it is, and whether it is a genetically modified product approved by China. At present, the developed chip can detect genetically modified crops that have been approved for commercialization at home and abroad: soybean, corn, rape, cotton, potato, tobacco, tomato, papaya, zucchini, sweet pepper and so on. General gene loci including promoter, terminator, screening gene and reporter gene are used to screen whether it is a transgenic product, and species-specific target genes including insect resistance, herbicide resistance, male sterility and fertility, restorer gene and variety-specific boundary sequence are used to determine which transgenic variety it is. 3.5 The trend of instrumental analysis With the continuous development of social economy, countries are gradually reducing the limit value of safety and hygiene indicators in food safety and hygiene control, which puts forward higher requirements for food safety detection technology. On the one hand, food safety detection technology tends to be high-tech, serialized and intelligent, which makes the detection instruments develop into complex instrument systems with high sensitivity and high selectivity, and the combination of analytical methods has become a hot spot in instrument analysis; On the other hand, the miniaturization and portability of on-site detection instruments are developing in the direction of specialization, rapid measurement, automation, intelligence and informationization. New dynamic analysis and nondestructive testing methods with high sensitivity and high selectivity and multi-parameter testing technology have become the development trend of testing technology. Biomimetic sensing technologies such as biosensor technology, biochip technology and electronic nose will surely play an increasingly important role. Therefore, there are five main trends in the rapid detection of food at present: (1) Due to the application of high technology, the detection ability is constantly improved and the detection sensitivity is getting higher and higher, and the ultra-trace analysis level of residues has reached10-7g; (2) Under the premise of ensuring the detection accuracy, the shorter the time required for food detection, the better. The detection speed is accelerating, and the use of intelligent chips, high-speed electronic devices and detectors greatly shortens the food safety detection cycle; (3) With the continuous improvement of selectivity, efficient separation and segmentation, and the use of various chemical and biological selectivity sensors, it is possible to directly determine the selectivity of pollutants in complex mixtures; (4) Due to the application of microelectronic technology, biosensor and intelligent manufacturing technology, detection instruments are developing towards miniaturization and portability, making real-time, on-site, dynamic and rapid detection a reality. At present, the products of food safety rapid detection technology on the market are mostly imported products or (5) products produced by foreign technologies, and the detection cost is very high. It is the general trend to localize the testing products, and to research and produce the fast food safety testing technology products with independent intellectual property rights in China. In view of China's special national conditions, the application of many rapid detection technologies in grass-roots units in China is still at the qualitative or semi-quantitative level, and the application of easy-to-use miniaturized instruments is the development trend of rapid detection technologies at present and in the future. In addition, food samples are complex and diverse, and the pretreatment is cumbersome and time-consuming. At the same time, the rapid detection method was established, and the sample pretreatment method was further improved, and a suitable small pretreatment device was developed. 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