Peanut is one of the top five oil crops in the world. It is widely grown in developing countries such as Asia, Africa, South America and some developed countries such as the United States. China is the world's leading peanut producer with an annual cultivated area of 5 million hectares, accounting for 20% of the total acreage in the world and ranking second. The output of 16 million tons accounts for 40% of the world's total output, ranking first. Aflatoxin is a secondary metabolite produced by Aspergillus flavus and Aspergillus parasiticus. It is of acute and chronic toxicity, mutagenicity, carcinogenicity, and teratogenicity. The toxicity of Aflatoxin B1 is 10 times than that of potassium cyanide and 68 times as much as arsenic. Arsenic is listed as a primary carcinogen by the World Health Organization (WHO). Peanut is one of the most vulnerable products to aflatoxin contamination. From every procedure of production to consumption, peanuts may be contaminated with Aspergillus flavus and produce toxins, which is extremely harmful to human health and food safety.
The pollution of peanut aflatoxin is a worldwide problem. It is the biggest and most important risk factor for safe consumption and the export of peanut oils and peanut products. This risk has received wide attention. The countries in the world and international organizations are subject to strict limits in aflatoxin AFT in producing, exporting and importing peanuts. Controlling aflatoxin AFT in peanut and peanut oil is a worldwide problem, and there is no fundamental solution.
In recently, the reporter received a report from a catering wholesaler, stating that he purchased peanut oil newly produced in an individual workshop this year from a grain and oil wholesale market in Guangzhou. The catering wholesaler sent the oil to the Guangzhou Analytical Testing Center for testing. The test report showed that the content of peanut oil in five pieces of bulk with aflatoxin B1 respectively over from 32 μg/kg, 70 μg/kg, 108 μg/kg, 120 μg/kg to 121 μg/kg.
At present, the national standard for the consumption of aflatoxin in peanut oil is up to 20 μg/kg. That is to say, peanut oil extracted from this batch of tested exceeds by 0.5 times in the minimum and up to 5 times in maximum.
And according to recent media reports, some of the peanut oil in bulk sold in the markets of Ganzhou and Zhaoqing in Guangdong province have excessive aflatoxins. The Guangxi Entry-Exit Inspection and Quarantine Bureau even detected aflatoxins exceeding 8 times in a batch of imported peanut kernels.
The sale of peanut oil in the Guangzhou market on survey
The sale of peanut produced by the individual workshop is still prosperous in the new grain and oil wholesale market of Sanyuanli. The reporter found that there are about five or six shops selling peanut oil in bulk, but these peanut oils in the container and outer packaging did not mark a product name, a production date, a shelf life, production and operation operators. The key information of products should be marked, such as a name and contact information. Although most merchants of selling oil in bulk claim that the quality of these new peanuts is guaranteed, they cannot provide relevant qualifications. As for this problem, the reporter visited several markets of grain and oil wholesale in Guangzhou and acquired the information from many merchants selling peanut oil in bulk that peanut oil comes from the private oil pressing mills in the surrounding, especially in Western Guangdong.
The oil extracted by this method of soil extraction is called raw oil in the industry. Taking peanut oil as an example, the raw oil produced newly will be very fragrant, due to the high temperature and residue of peanut oil. It lacks the necessary process in finishing, so it is generally difficult to meet the national safety standards for edible oils. Aflatoxin is the most common unsafe factor, and heavy metal and pesticide residues exceeding the standard and are also need to be guarded. Chen Zijia, vice president of the Guangzhou Food Association told reporters.
This kind of peanut will soon usher in the booming season on the market, which is driven by the interests. In this case, there will more problems with oil. Some insiders told reporters that the weather conditions in several counties and cities in western Guangdong are almost the same, but the newly squeezed peanut oil exceeds the standard by 0.5 times and even by 5 times. It suggested that maybe there are other factors to affect the content of Alatcxin in oil, except for natural factors."
The reporter asked that if peanut oil in bulk that was bought had the problem, who is responsible for it? A grain and oil store owner who asked not to be named said that most people would find the shop in his buying. But due to the lack of necessary testing or qualification certificates, it is difficult to say whether the manufacturer or the dealer has a problem.
Why do aflatoxins exceed the standard in peanut oil in bulk?
In the interview, the equipment and environment in western Guangdong are poor in oil production compared with regular manufacturers.
The method of extraction in pressed peanut oil is simple and direct. Therefore, many consumers think that the soil is pure without addition. But what is the actual situation? The reporter recently went to Yangdong and Yangjiang for investigation in this problem. At a distance of fewer than 300 meters from the Yangdong Tangwei pedlars' market, there are 6 workshops to produce peanut oil, and consumers pass by and see the portable oil from time to time. The workshop in oil pressing is generally small, with a small size of nearly 10 square meters and no more than 40 square meters on a large scale. The peanuts are piled together randomly, and the equipment in oil pressing is rusty. And the sanitary condition of the oil drum is worrying. The oil filled in large quantities of plastic drums or even recycled mineral water bottles, the entire oil processing has been exposed to harsh environments where hygiene is not guaranteed.
The situation in Yangjiang is similar to that in Yangdong. The reporter also learned that the price of new pressed peanut oil in Zhaoqing is about 10 yuan/kg. The price of Yangjiang is about 9 yuan/kg. The price of Maoming and Zhanjiang is higher,10 to 15 yuan. The owner in the workshop emphasized that they sale 100% pure peanut oil. The price proves that it is without problems. If the price is too low, there must be problems. But an industry insider told reporters that now peanuts in high quality is about 7 yuan/kg, and peanuts in low quality are also 5 yuan/kg. The highest rate of oil production in peanuts is 1kg by using 3 pounds of peanuts. Even with the worst peanut oil, the cost of raw materials is higher than the price of Tuza oil. Therefore, peanut oil is likely to be blended with soybean oil, but more blended with cheap palm oil. And there is also a blending with ditch oil without conscience.
There are risks of security in the oil produced in the individual workshop and home. As the two most important agricultural products, peanuts, and corn that are easily contaminated by aflatoxins, and they are also the main source of edible oil. In recent years, with the public's desire in the concept of tradition, farmhouse, in self-made, pure nature and original ecology in the field of food consumption, oils produced in the small oil pressing mills and homes are popular. Regarding these two methods of oil extraction, experts believe that there are major risks in the safety of oil.
Wang Qiang, the researcher and deputy director of Institute for Agricultural Products Processing of the Chinese Academy of Agricultural Sciences, pointed out that except for the possibility of contamination of the raw materials, oils produced in individual workshops and homes still have the following problems. It has not been refined, remains many impurities in the oil, is easily oxidized and deteriorated and is not easy to clean residue in the equipment. Residual in oil and grain will cause mildew after oxidation and food safety are serious in these oils. And low utilization resources will cause great waste.
Although edible oil is easily contaminated by aflatoxin, control methods can reduce aflatoxin in finished oil to a very low level, including raw material screening, alkali refining, and adsorption, said Wang Xingguo. However, this method of quality control is difficult to guarantee in small workshops and at home.
Experts say that natural conditions in western Guangdong are not conducive to peanut in storage. In the interview to visit Guangdong by the reporter, it was learned that the preference of peanut oil in western Guangdong can be described in rootedness. The specific reasons are mainly that peanut oil is rich in nutrients and easy to absorb and digest, and the pressed peanut oil is more fragrant than packaged peanut oil. Besides, the report of food safety frequently exposed in recent years has also made consumers psychologically more inclined to a product labeled with farm and homemade.
Some experts in food safety believe that western Guangdong with a big scale on peanut planting is very different from Shandong. Both of the places have the advantage of planting peanuts in natural conditions, but western Guangdong is not as good in the natural conditions of storing peanut. That is to say, although the natural conditions in western Guangdong are suitable for planting peanuts, the disadvantages of hot and humid weather in peanut harvest are extremely detrimental to the storage of peanuts, which is the main reason for the growth of aflatoxin. Besides, the processing in oil lacks the refinement procedure to remove aflatoxin, and the sales in bulk of oil lack the necessary food safety supervision. Therefore, repeated problems are inevitable.
Experts suggest that food production, processing enterprises and especially the individual workshops taking corn, peanuts, etc. as the main raw materials, should strictly implement the national food safety standards and relevant technical specifications, pay attention to the safety of raw materials and strictly control every link in production to ensure the quality and safety of products.
Why does aflatoxin often exceed the standard in the oil produced in an individual workshop?
The scent in homemade and traditional oil with farmer's peanut oil attracts people's attention. Although the name is not the same, it is the same, simple and traditional method of vegetable oil in pressing. Many people hold the idea that although the color is deep, it is the same color of oil eaten in our childhood. This is the oil that I observed in producing, and it must be reliable oil. But if the pressed peanut oil is taken by testing, the content of aflatoxin in it will probably in great amount.
Aflatoxins in agricultural products are almost inevitable such as aflatoxin peanuts and aflatoxin corn. Some people will emphasize that I have checked raw materials in peanut, and it is with no mold. The problem is that aflatoxin is invisible to you, and even if the peanuts look well, they may be contaminated with toxins. The warm and humid climate is more suitable for the growth of Aspergillus flavus and Aspergillus parasiticus produced toxins. Therefore, Aflatoxins are common in agricultural products.
Does the peanut oil produced in the factory exceed aflatoxin? In the national standard 2761, it specifies a limit indicator of aflatoxin B1 in food. The limited standard of peanut and corn oil are 20ug/kg, and it is 10ug/kg in other vegetable oils. This indicator is much lower than the content of aflatoxin in general agricultural products and does not affect human health. In addition to the limited standard of mycotoxin, pesticide residues and pollutants (such as lead, cadmium, mercury and other metal contents) in vegetable oils and fats are also limited. Plant oil products produced by the factory must meet the criteria mentioned above.
It can be seen that the focus in problems is that the oil produced in a factory and individual workshop raw oil is the only semi-finished product. Oils produced in an individual workshop are sold and consumed as finished products, and there are possible with Aflatoxin.
The content of free fatty acids, phospholipids and pesticide residues is also higher in oil produced by individual workshop. Raw oil is inevitable along with impurity that is harmful to health and will shorten the shelf life.