■Ground oil event playback In September 2011, the public security departments in Zhejiang, Shandong, Henan and other places cracked a series of cases involving the use of waste oil to produce edible oil for the first time, destroying the “ditch oil†criminal network involving 14 provinces, one set of fishing and coarse The black industrial chain of the waste oil in the six links of refining, reselling, deep processing, wholesale and retail has surfaced. The police have evidence that the waste oil produced by Jinan Green Bio-Energy Co., Ltd. has flowed into the grain and oil wholesale markets in Henan, Shandong and Hebei. As a result, the rumors that the “ditch oil†flowed to the table were confirmed. “You must have eaten the waste oil.†He Dongping, a professor at the School of Food Science and Engineering at Wuhan Institute of Technology, told reporters that his other identity is the head of the Oil and Fats Working Group of the National Grain and Oil Standardization Committee. According to his estimation, the amount of waste oil that returns to the table every year in China is 2 to 3 million tons. The total amount of animal and vegetable oil consumed by the Chinese in a year is about 22.5 million tons. That is to say, according to the ratio, if you eat 10 meals, there may be one touch of waste oil. What is the main component of the waste oil? What is the harm to the human body? How to detect the waste oil? As a professional media in the domestic bio-industry, China Biomaterials Network has made special reports on this. ■The main components of the waste oil Fast Shipping Laser Distance Sensor Hi there, Fast Shipping Laser Distance Sensor,Serial Laser Distance Sensors,USB Laser Distance Sensors,RS232 Laser Distance Sensors Chengdu JRT Meter Technology Co., Ltd , https://www.cdlaserdistancesensor.com
On March 20, 2010, the law enforcement officers of the Food Inspection Branch of the Food and Drug Administration of Xi'an City found that there was a water-recovery oil recovery device at the Chongqing Fatma Rotten Hot Pot Xi'an Head Office. The on-the-spot bill also indicated that the hot pot restaurant was suspected of recycling the waste oil. Accordingly, the Food Inspection Branch of the Food and Drug Administration of Xi'an was suspected of recovering the secondary use of the water-repellent oil, violating the Food Safety Law, and ordered the store to suspend business for rectification. The incident caused a denunciation of the waste oil across the country, but so far the trench oil has not disappeared.
â–ª Preliminary analysis
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Ditch oil is actually a general concept, and it is a general term for people in various types of inferior oil in their lives.
The composition of the waste oil is similar to that of ordinary oil, which means that there are many impurities. In the traditional sense, the waste oil in the total number of bacteria, biogenic amines, acid value, cholesterol, carbonyl price, malondialdehyde, heavy metals, acrolein and other indicators are seriously exceeded. Ingestion of the human body can cause cell failure, induce a variety of diseases, and even cause cancer.
“At present, there is no specific testing standard for waste oil in China.†Lu Yong, director of the Municipal Food Safety Monitoring Center, told reporters that it is safe and safe to test edible oils and fats, based on the implementation of “food vegetable oil hygiene†from October 1, 2005. standard". However, this standard is usually used to determine whether the edible oil produced by the company is qualified. It does not take into account the extremely poor “production†method of “ditch oilâ€. Therefore, the existing national standard cannot be used to determine whether the oil belongs to the trench. oil.
The Beijing Food Safety Office said that since June 2011, the Beijing Food Safety Monitoring Center has organized industry-wide testing experts to conduct an assessment of the “ditch oil†identification technology. Without the “ditch oil†sample, the tester will set up the wok to simulate the real version of the “ditch oil†production process, and then take up the container to boil, separate the oil and water, then remove the impurities with the adsorbent, deodorize and refine with activated carbon. ...... In the past three months, the inspectors have comprehensively applied more than 80 technical indicators to the oil residue by using modern analytical testing methods such as chromatographic analysis, spectral analysis, physical and chemical analysis and genetic identification technology. The identification of the four types of effective indicators for the determination of "ditch oil" was finally established, and the index system for the detection of "ditch oil" was initially established.
â–ª Four types of indicators give the trench oil a prototype
The first indicator: polycyclic aromatic hydrocarbons (PAHs). Polycyclic aromatic hydrocarbons (PAHs) are aromatic compounds containing a plurality of benzene rings produced by heating, such as frying, roasting, frying, frying, etc., which are POPs. Most PAHs have been listed as carcinogens by the International Cancer Research Center. .
The second indicator: cholesterol. Edible vegetable oils generally do not contain cholesterol or are extremely low in content. The technician may, based on the fact that the waste oil may contain animal-derived components, conclude that if the cholesterol is detected and exceeds a certain range, the grease may be suspected to be a waste oil.
The third indicator: conductivity. Normal fats are almost non-conductive, but the various polar substances produced by the rancidity of the oil can make the grease conductive. The trench oil is electrically conductive due to the doping of a large amount of metal ions, and the electrical conductivity is high.
The fourth indicator: specific genetic composition. The waste oil is a mixture of waste oils from many different sources, often containing animal fats. The tester identifies the animal genes in the oil according to the molecular biological genetic identification method to determine whether the edible oil contains animal-derived ingredients. Dr. Zhao Linna from the testing center told the reporter: "It is extremely difficult to extract a very small amount of animal DNA fragments from oil, which is the animal's genetic sequence. It is a technical obstacle in the world. We have tried many methods to find the animal. The genetic approach."
â– Detection of the oil component of the trench
It can be seen from the above that if the parameter parameters such as polycyclic aromatic hydrocarbons (PAHs), cholesterol, electrical conductivity, and specific gene composition of the sample oil are obtained experimentally, it can be concluded whether the oil sample is a waste oil. The following is the relevant information collected and organized by China Biomaterials Network for reference by interested friends.
â–ª Polycyclic aromatic hydrocarbons (PAHs)
Wu Xuemei et al. used high performance liquid chromatography to determine polycyclic aromatic hydrocarbons (PAHs) in foods. They selected fluoranthene, benzo (k) fluoranthene, benzo (b) fluoranthene, benzopyrene (BaP), benzo (g, h, i) and other polycyclic aromatic hydrocarbons with carcinogenic or mutagenic effects. The content in the food was measured. Studies have shown that the detection limits of fluoranthene, benzo(k)fluoranthene, benzo(b)fluoranthene, benzopyrene (BaP) and benzo(g,h,i)pyrene are 0.12,0.0128,0.0214, respectively. 0.0412, 0.126 ns / mL (injection volume of 5 dishes), the limit of quantification is 0.4, 0.0428, 0.0713, 0.137, 0.42 ng / mL recovery within 85% -100%. The method has high sensitivity, simple operation and accurate quantitative. [Click to download related articles, extraction code: ca0bhq9a ]
â–ª cholesterol
Guo Tao et al. used high performance liquid chromatography to determine the cholesterol content in the waste oil, and then qualitatively analyzed whether the cooking oil was mixed with trench oil. The experimental results show that when the content of cholesterol in the rapeseed oil sample is more than 0.05mg/g, the cholesterol peak can be clearly observed, and the cholesterol content in rapeseed oil increases linearly with the increase of the waste oil. The edible vegetable oil did not detect cholesterol. This feature can be used as a basis for judging whether or not the trench oil is blended in the vegetable oil. [Click to download related articles, extraction code 8b1mc30p ]
â–ª Conductivity
Zhu Rui et al. identified the method for detecting the incorporation of edible vegetable oil into the trench oil by conductivity measurement. By comparing the conductivity of the trench oil, qualified edible oil and adulterated edible vegetable oil, the results showed that the average conductivity of the aqueous phase after extraction was 100.7 μs/cm, which was 10 times that of rapeseed oil and 10 times that of soybean salad oil. 11 times. The waste oil was incorporated into rapeseed oil with different mass fractions. The adulteration was linear with the conductivity. The one-way analysis of variance showed that the adulteration had a significant effect on the conductivity. The linear regression equation was Y = 91.41X+12. .49, R2 = 0.996, the difference was statistically significant (Ï < 0.01). Conductivity can be used for the identification of waste oil mixed with edible vegetable oil. [Click to download related literature, extract code so8cmqur ]
â–ª Specific gene composition
Wu Shan et al. studied the target genes transferred to the transgenic products, as well as the promoter and terminator, and designed the corresponding primers 35SCP142 and CPNOS165. By adjusting the primers, the size of the PCR amplification product is controlled to be 100 to 170 bp, thereby improving the detection sensitivity. In a 25 μl PCR reaction system, 0.01 ng of exogenous DNA can be detected. [Click to download related literature, extract code fefo3snm ]
â– Summary
This paper focuses on the detection of four types of indicators for waste oil through some common analytical techniques. It is believed that through the concerted efforts of the government, the regulatory authorities, and the people, the waste oil incident will no longer meet us.
NEW latest report (October 13th):
Ditch oil no test standard
At present, there is no unified standard for detecting waste oil in China. The current national mandatory standard "Sanitary Standard for Edible Vegetable Oils" (2716-2005), the physical and chemical indicators for edible oils include acid value, peroxide value, solvent residue of leaching oil, free phenol (cotton seed oil), total arsenic, lead There are 9 indicators of aflatoxin, benzopyrene and pesticide residues, which are tested differently for plant crude oil and plant edible oil.
However, vegetable crude oil and vegetable edible oil are not waste oil. Experts said that the nine basic edible oil detection indicators in the standard, even the oil from the trench oil, may be qualified, and it is impossible to conduct discrimination detection for the waste oil.
Experts say that the Beijing Food Safety Monitoring Center's test indicators are difficult to identify the trench oil
Yesterday, Deng Haihua, a spokesperson for the Ministry of Health, revealed that the experts used a professional “double-blind†experiment to identify the method of detecting waste oil. "Double-blind" experiments are often used in the effects of new drugs. Relevant persons from the China CDC explained to reporters that during the verification process, one group was cooking oil and the other group was different concentrations of waste oil. Experts did not know the specific grouping and used the collected method. Check the oil one by one to see which method can effectively separate the two oils, but unfortunately the "results are not good."
I took the waste oil and couldn’t measure it.
Previously, the Beijing Food Safety Monitoring Center released that the most critical test for trench oil is to test four core indicators, namely polycyclic aromatic hydrocarbons, cholesterol, conductivity and specific genetic composition. Among them, the carcinogen polycyclic aromatic hydrocarbons are considered to be the largest hazard component of the current safety risk of waste oil.
However, in this negative method, we also refer to the indicators proposed by Beijing. Chen Junshi, a researcher at the China National Center for Disease Control and Nutrition, and a member of the Chinese Academy of Engineering, said that the detection method of the currently used waste oil should be reliable and specific. However, the current experimental methods are not acceptable. "I clearly took the waste oil test, but I can't detect it."
Taking Beijing's detection method as an example, after the special treatment of the waste oil, it was found that not all the waste oil samples contained polycyclic aromatic hydrocarbons. Therefore, Beijing's indicators are not acceptable in identifying trench oil.
Editor: China Biomaterials Network will continue to track the latest developments in trench oil testing, so stay tuned!