The method of pressing in peanut oil is labeled with multiple labels such as tradition, nature and original ecology. Peanuts, corn and other crops are most susceptible to contamination by Aspergillus flavus. Is the oil qualified in peanut oil produced from the individual workshop and the bulk of the raw oil eaten in the restaurant? Nandu appraisal agency collected 8 bottles of raw oil in bulk from restaurants in Guangzhou, Dongguan, Maoming, Zhanjiang, Yunfu and other places. In cooperation with Guangdong Food Inspection Institute, the content of aflatoxin B1 in peanut oil was tested and identified. Labels from tradition, nature to original ecology, etc., just cater to many people's psychological needs.
Some people even think that only the foods that are produced in front of them that are reassuring. Therefore, the sales method in the oil-pressing workshop is also a typical representative, which refer to sale and press oil in the shop. Oil pressed in individual workshop smells quite fragrant, the price of some pressed peanut oil is lower than that of the brand oil in packaging, so some oil bulk also flows from the workshop to the restaurant.
If the peanuts are moldy, the oil made from peanuts may also produce a toxin in aflatoxin. Hong Zezhen, an inspector of the Guangdong Food Inspection Institute, said that aflatoxin is a heat-resistant mycotoxin that is difficult to destroy at the temperature of general cooking and processing. Only when the temperature reaches 280°C, can the toxin in aflatoxin be decomposed.
Aflatoxins have been classified as Class 1 carcinogen by the World Health Organization, due to the clear evidence of carcinogenicity in humans. Aflatoxin B1 is one of the most known carcinogenic chemical and the most common aflatoxins in natural foods. Peanuts, corn, etc. are most susceptible to contamination by Aspergillus flavus, so aflatoxin B1 is a mandatory item for the sampling of food safety inspection in edible vegetable oils.
8 bottles of peanut oil sampling in bulk produced in individual workshop
2 samples exceeded the standard of aflatoxin B1
Time: On the morning of February 10th
Location: Guangdong Food Inspection Institute
Sample: 8 bottles of peanut oil in bulk produced in an individual workshop taken from restaurants
Instrument: High-Performance Liquid Chromatograph
Objective: To detect the content of aflatoxin B1 in 8 bottles of peanut oil
Inspection standard: GB 5009.22-2016 National Standard for Food Safety in Detection of Aflatoxin B and G in item three. (post-column photochemical derivatization.)
The engineer of the Guangdong Food Inspection Institute is responsible for this inspection and make clear that to know the content of aflatoxin B1, you need to weigh 5g oil and add 20ml of 70% methanol. Aflatoxin B1 will dissolve in methanol, you need to spin it for 3 minutes and centrifuge it on the centrifuge. At this point, the oil and extract will be stratified and the aflatoxin in oil will dissolve in the methanol. Subsequently, the toxin was selectively adsorbed by an aflatoxin B1 immunoaffinity column, and the content was finally detected by high-performance liquid chromatography.
In GB 2761-2017 National Standard for Food Safety in Limited Standard of Fungaltoxin specified the limit of aflatoxin B1 in foods. The content of Peanut oil aflatoxin B1 is limited at 20 μg/kg. The testing results showed that in the 8 samples, 2 exceeded the standard and 6 qualified. In the unqualified samples, the content of aflatoxin B1 in one sample in the Panyu District of Guangzhou City was 38.4 μg/kg, which nearly double the standard. And the content of aflatoxin B1 in one sample in the Luoding city of Yunfu province was 78.3 μg/kg, which nearly three times higher than the standard value.
Edible vegetable oil in Cantonese restaurant passes the rate of over 90% in a random inspection. In 2017, the Guangdong Food and Drug Administration supervised and inspected the edible vegetable oil in restaurants under its jurisdiction, with the pass rate of 93.55% overall. By comparison of test results, the qualified rate of edible vegetable oil in Guangdong restaurants is higher than the average level in other regions and it’s the overall quality in level is better.
Hong Zezhen said that in the sampling inspection, more than 90% of restaurants use edible vegetable oil with a customized package instead of edible vegetable oil in bulk. The risk of aflatoxin B1 in peanut oil in bulk is significantly greater than that of peanut oil in customized packaging. In Beijing, Shanghai, Hainan, and other provinces and cities, there has been a prohibition order. A comprehensively ban is prohibited edible oils in bulk entering the catering industry. And Guangdong has also implemented this order in the canteen for the consumption of edible oil in bulk to provides an important guarantee in oil. However, this measure has not been implemented nationwide, and the quality and safety of oil in bulk still exists.
Why Aflatoxin exist in peanut oil produced by an individual workshop?
The inspector said that the individual workshop produced oil lacks deep processing and there are more residual toxins. Hong Zezhen said that the climate in Guangdong is warm and humid, especially suitable for the growth and production of Aspergillus flavus. Peanuts are susceptible to moisture and mildew in storage and are more susceptible to Aspergillus flavus than other grain and oil crops. And this toxin is so small that it can not be seen by naked eyes. Even if the peanut looks good, it may be contaminated with toxins. Although edible oil is easily contaminated by aflatoxin, control methods, such as raw material screening, alkali refining, and adsorption can reduce aflatoxin to a very low level in the refined oil.
The oil obtained by a factory after rough processing in pressing is called raw oil, which is nearly the same quality of oil produced in the individual workshop. It may contain aflatoxin in this procedure, and it also contains many impurities such as free fatty acids, phospholipids, pesticide residues, etc. However, in the factory, the oil is only a semi-finished product and it needs to be refined. It is processed through degumming, deacidification, decolorization, deodorization, etc., including detoxification of aflatoxin. And refining can reduce the content of aflatoxin in peanut oil. After the oil is produced, the production personnel will also test the content of aflatoxin and make it meet the standard before the sale of oil.
Stir-firing peanuts with Aflatoxin B1 before pressing is unable to remove aflatoxin. To make peanut oil produce fragrance and improve the peanuts oil in yield, peanuts will be fried before pressed. People take and convince it as also a disinfection process in oil manufacture. Hong Zezhen said that such a temperature can only kill mold in oil, but the pyrolysis temperature of aflatoxin B1 is up to 280°C. Generally, the cooking will not reach this temperature to pyrolysis, let alone detoxification in the oil. Moreover, if the temperature of the frying is not controlled well, it is possible to produce strong carcinogen benzopyrene. Besides, the peanut oil has a high content in fat. The method used in the individual workshop is liable to cause oxidative rancidity, which not only reduces the nutritional value but also deteriorates the taste. Ingesting oil produced by this method may cause symptoms such as nausea, vomiting, diarrhea after eating and endanger the body healthy.
In the limit indicator of Aflatoxin B1, peanut oil and corn oil were 20 μg/kg. Other vegetable oils and fats were 10 μg/kg. What is the risk of the exceeded standard to humans? Zhou Lu, the director of the Department of Bioassay and Institute of the Provincial Food Inspection, said that aflatoxin B1 is metabolized in the human body after being eaten along with food and will cause carcinogenicity. But it will not cause cancer by a small amount of ingested aflatoxin B1. It is possible to have problems in edible oils with excessive toxins accumulated toxicity in long-term consumption. When it caused cancer, liver cancer is more common. If people carry a hepatitis B virus, the carcinogenic effect will be stronger in them.
How to choose peanut oil correctly?
Hong Zezhen stressed that the contamination of aflatoxin B1 in peanut oil does not need to be exaggerated, and people need to strengthen their confidence in food safety. After rectification in this specialized item, the contamination of aflatoxin B1 in bulk of peanut oil has improved, but it is still at a relatively high level. It’s rectification not need government supervision, but also needs to establish a correct concept of consumption of edible oil by people.
1. Purchase peanut oil in medium or large-sized shopping malls, supermarkets or stores that hold the Food Permit in Circulation.
2. Preference is given to pre-packaged peanut oil with large brands, high credibility, and good reputation.
3. When purchasing pre-packaged peanut oil, the label of product should be marked with the production license number in the enterprise of food production, like SC+14 Arabic numerals. The license can be checked on the official website in the State Administration of China for authenticity.
4. When purchasing edible oil in bulk, you should choose it with food labels, which is marked with the name of oil, the type of ingredients, the date of manufacture, the shelf life, the manufacturer, the address, and the contact type.
5. Do not purchase peanut oil without a production date, a quality certificate (or production license), a manufacturer name or with ambiguous information in label and an excessive time limit.