According to media reports, aflatoxin M1 was detected in the two brands of fresh milk recently. The national limited standard was 0.5μg/kg, and the measured value was 1.2μg/kg in the sampling inspection. The article entitled strong carcinogen aflatoxin exceeded 140% in milk was published on the headline of major newspapers. A lot of people raise the questions that What harm does aflatoxin cause to the human body? Will we be poisoned? Do we need to stop drinking milk? It prompted me to write this blog. The pollution incident once again proves that the process of production in food needs to be controlled strictly. Fortunately, the contaminated fresh milk has been destroyed and sealed, not entering the market.
In briefly, aflatoxin M1 is a carcinogen to humans, but exceeding the standard value does not necessarily mean poisoning. The induction of poisoning also depends on the amount of aflatoxin M1 that can be eaten. From the perspective of risk assessment, if you are not lucky or mistakenly eat moldy foods like in seeds, peanuts, nuts, rice, soybeans, etc., stored at home improperly, it may produce much more toxicity than in milk. The moldy product contains a great deal of toxicity and the carcinogenic toxicity of aflatoxin B1 is 10 times more than aflatoxin M1. As to the content of toxin in this pollution, drinking one or two times should not cause cancer or poisoning, but there is a great health risk in long-term drinking.
The toxicity of aflatoxin is a kind of natural product. Some crops (like corn) may have produced aflatoxin in the field. Countries are strictly controlling the growth of aflatoxins and the production of aflatoxin in storage and other links.
1. Aflatoxin is a common natural pollutant
Aflatoxin is a metabolite produced by Aspergillus flavus and Aspergillus parasiticus. In the case of rainy and hot days, if the grain is not dried in time and stored improperly, it is often easier to contaminated by Aspergillus flavus or Aspergillus parasiticus and produce such toxins. Aflatoxins exist in soil, and aflatoxins are often found in various nuts, corn, soybean rice, milk, and dairy products, especially in nut like peanuts, walnuts, melon seeds.
2, Aflatoxin is classified as class A carcinogen
In 1993, aflatoxin B1 has classified as a class 1 carcinogen to humans by IACR. The harmfulness of aflatoxin is that it has a destructive effect on human and animal liver tissues, and can cause liver cancer or even death in severe cases. There have been a large number of livestock and poultry poisoned by aflatoxins and even death in the world. The chronic toxicity of aflatoxin is mainly manifested in liver damage induced malignant tumors in digestive systems such as liver cancer.
Extensive research has been conducted in Asian and African countries where the rate of contamination in aflatoxin is particularly high in foods. The results show that food exposure to aflatoxins can increase the risk of liver cancer in residents, especially hepatitis B and hepatitis C-positive people. Due to the strong carcinogenicity of aflatoxin, no guidance values in healthy with aflatoxin were established.
3, Aflatoxin M1 is a metabolite of aflatoxin B1
More than ten aflatoxins are isolated currently, aflatoxins B1, B2, G1, G2, and M1 are focused mostly. Among the naturally contaminated foods, the presence of aflatoxin B1 is more common, and it’s toxicity and carcinogenicity are also rich. The carcinogenic toxicity is different between Aflatoxin M1 and Aflatoxin M1 because aflatoxin M1 is a metabolite of aflatoxin B1.
JECFA estimates that the carcinogenicity of aflatoxin M1 is about 1/10 of aflatoxin B1 (JECFA, 2001.2). The cow ate a feed containing aflatoxin B1 and there will be aflatoxin M1 in the milk.
4, how to avoid contamination with aflatoxin in dairy products?
The source of this incident in excessive aflatoxin of fresh milk was that the feed eaten by cattle was contaminated by a high level of aflatoxin. As mentioned above, if corn and peanuts do not dry in time to reduce the moisture under the conditions of rainy or high temperature, the probability of producing and multiplying in aflatoxin is quite high. This is the status quo, which means that it is very difficult to completely avoid the production of aflatoxin. This is a major challenge for the current feed industry and its management, so special attention should be paid to the regulation of the feed of cattle.
The dairy industry should check the source of feed strictly. It is relatively easy to manage the feed on the dairy farm by the dairy company, and they just need to inspect in every batch of the samples in the test. However, if buy fresh milk from retail investors, it is impossible to control the content of aflatoxin in the feed. Fresh milk only can be control in the content of aflatoxin under a strict traceability system and inspection of batches. Once the food in contamination with aflatoxin is discovered, it can only be destroyed and manufacture needs to bear the losses by themselves. One of the common ways for dairy companies to dominant in the competition is to collect fresh milk from retail investors. However, the incidents of pollution included melamine event, have proved that the risk of acquiring fresh milk from retail investors is very high, so the stakes must be weighed between the advantage and disadvantage.
5, Consumer does not need to worry too much
Although aflatoxin is very carcinogenic, it is not as terrible as the media publicity for consumers. The reasons are the following. On the one hand, according to reports, this batch of contaminated fresh milk did not flow into the market. On the other hand, the pollution of aflatoxin in food is very strong with climatic factors, because aflatoxin is unstable. Corn, peanuts and fresh milk are more susceptible to aflatoxin contamination, but this product eaten by consumers is not polluted or lightly polluted in most cases (by the standard). It is only a few or few cases exceed the standard in aflatoxin, including this incident of excessive aflatoxin in fresh milk. Therefore, it is unlikely that consumers will repeatedly eat foods with exceeding the standard in aflatoxin.