Experiments show that most of the refined cooking oil meet the edible oil standards

The turbid, foul-smelling waste oil has been refined to meet the national edible oil standards. For some time now, the public has focused their attention on waste oil testing standards. The Dongfangnet reporter learned that Shanghai scientific research institutions have initially established a rapid screening method that can easily screen for waste oil in 1-2 minutes. Experts also expect that “in the near future, 100% scientific and accurate inspections with the basis of law enforcement will be formed. The standard is still very difficult."

It is highly likely that the cooking oil will be transformed into sesame oil

Industry sources told the Oriental Network reporter that the return of cooking oil to the dining table involves collection, transportation, preliminary refining, circulation, refining, and circulation. At present, the cost of purchasing one ton of original waste oil is about 4,000 yuan and 5,000 yuan. The ex-factory price of oil-refined underground plants is about 8,000 yuan, plus the portion of refinery, the profit of refineries is about 1,000 yuan per ton of oil.

As for the whereabouts of the return of cooking oil to the table, it was revealed that it is very likely that it will be transformed into sesame oil. "One ton of soybean oil is priced at ten thousand yuan, and one ton of sesame oil can be sold at about 27,000 yuan. More importantly, the color of sesame oil is deep and there are odors."

An interview with the Oriental Network reporter found that unreasonable cooking habits and legitimate corporate illegal activities directly contributed to the return of cooking oil to the table.

In times of material poverty, ordinary families cherish the use of edible oils more often, and frying and frying often use oil repeatedly. It is reported that the habit of using old oil is still retained even in five-star hotels. “If the old oil is dark, the hotel will filter it by itself, or use it for braised dishes such as braised dishes, and finally it can be used for frying. Chili oil.” The original intention of the hotel and restaurant, in addition to cost savings, but also because the old oil aroma, especially in line with the people's food needs.

In addition, during the enforcement process of the relevant departments, it was discovered that some manufacturers or companies with formal operating qualifications under the cover of the “environmental protection, science and technology” legal cloak have done illegal activities. Previously, Shanghai had investigated and dealt with a number of related cases. The lawbreakers used various kinds of items such as diesel oil to cover up illegal acquisitions and reselled waste oil. It is understood that in some areas of other provinces and cities, some legitimate production companies also involved in waste management. “The normal operations of the feed oil plant will be exposed to waste oil, and it is normal for large oil tankers to enter the factory area. The refined and degreased oil in the plant basically meets the standards for qualified edible oil, and they may return to the table at the next home. The factory can also In order to shirk responsibility without knowing what customers are buying."

Refined trench oils mostly meet edible oil standards

As waste oil is ramping up the market, scientific tests are in vain.

The definition of waste oil in academic circles is still inconclusive. The general concept is that of all waste edible oils. The specific ones mainly include three types of waste oils from restaurant kitchen waste oil (or dip oil), fried oil, and drain oil. In the laboratory of the Shanghai Institute of Grain Science and Technology, the Dongfang Net reporter saw nine kinds of waste oils that were placed in separate groups, namely crude oil for frying oil, fried old oil, and drain oil, and refined oil that was decolored and deodorized. From a sensory judgement, the refined cooking oil that has been decolored and deodorized is clear and translucent, almost no difference from regular cooking oil.

According to researchers, starting from July 2010, the Shanghai Municipal Science and Technology Commission officially initiated a project to study the “oil production” testing method and established the largest domestic waste oil sample bank. Up to now, the research group has collected more than one thousand samples, including both original waste oil and suspected refined gully oil circulating in hundreds of markets, especially to Shanghai and the surrounding Jiangsu and Zhejiang regions.

"The vast majority of waste oil can meet the national edible oil standards after filtration, decolorization, and deodorizing refining." Experiments show that the refining of trench oleic acid is comparable to the current national "Sanitary Standard for Edible Vegetable Oils" (GB 2716-2005). Physical and chemical indicators such as price and peroxide value are very close to or completely meet the national standards. However, the existing methods for the detection of various kinds of waste oil have certain flaws, or the specificity of the characteristic index is not strong, or the detection sensitivity is not high, or the detection accuracy is not high, and none of them can be an effective supervision tool for the detection of adulteration of waste oil. .

2 minutes rapid screening method initially formed

The degree of grease oxidation can reflect the deterioration of oil quality and freshness, and what indicators can be used to differentially identify waste oil? According to reports, the processing of waste oil can remove free fatty acids, degrade or convert hydroperoxides, and traditional indicators such as acid value and peroxide value for detecting deterioration of oils are difficult to exert. To this end, the Shanghai Municipal Food Science Research Institute took the lead in proposing and fundamentally demonstrating the characteristics of waste oil, namely oxidized triglyceride polymers, and established a detection method. Experiments have shown that oxidized triglyceride polymers “only increase unabated” in the process of waste oil refining. In particular, the accuracy of detection of refined oils for frying old oil and refined oil can be almost 100%.

However, the researchers frankly stated that this method has not yet fully grasped the detection of swill oil, especially for swill oils with a low degree of oxidation, and unscrupulous traders tend to mix refined gully oils with good oils during the inspection process. Misjudgment.

While studying high-level testing methods, the Shanghai Institute of Food Science has also locked in the research of rapid screening methods. At present, a method for rapid screening of waste oil for 2 minutes has taken shape. Researchers used low-field nuclear magnetic technology to detect hundreds of samples of old oil and drain oil with an accuracy rate of almost 100% and an accuracy rate of about 70%. With the rapid testing equipment being developed, this method helps the frontline law enforcement work in the future.

"In the future, the detection of waste oil may adopt a combination of indicators." Experts have judged that "it will take time to really form a detection technology with the basis of law enforcement." "Before there is a scientific and accurate arbitration test method as a support, the rapid screening method is also It is difficult to play a big role alone."