What causes aflatoxin in milk?

Everyone knows that mildewed beans and cereals may contain aflatoxin, but have you ever thought that the milk powder for babies or adults and the elderly also contains aflatoxin? That is how it is, aflatoxin is not only the presence of spoiled legumes and cereals but also our milk powder in milk markets, which has a certain probability of containing aflatoxin. Have you ever thought about why there is aflatoxin in milk powder? What is the harm of aflatoxin? What can be done to eliminate it? This article will give you an answer.


1. Let's first know what aflatoxin is.

Aflatoxin (AFT) is a class of compounds with similar chemical structures, which are derivatives of dihydrofuran coumarin. Aflatoxin is a secondary metabolite produced mainly by Aspergillus Flavus Parasiticus. It is most likely to occur in food and feed in hot and humid areas. They exist in soil, animals and plants, nuts, especially in peanuts, maize, rice, soybean, wheat, and other grain and oil products. They are the most toxic mycotoxins, which are extremely harmful to human health.

Aflatoxin was classified as a carcinogen in food by the Cancer Research Institute of the World Health Organization (WHO) in 1993. It is a highly toxic and highly toxic substance. Aflatoxin can destroy human and animal liver tissues and even cause liver cancer and death in severe cases. Among naturally contaminated foods, aflatoxin B1 is the most common. Its toxicity and carcinogenicity are also strongest.

Aflatoxin is mainly divided into B1, B2, G1, G2, M1, M2, P1, Q, H1, GM. The most common dairy products are aflatoxin M1 and M2. M is the abbreviation of milk.

2. What effect does aflatoxin have on us?

Flavomycin is very toxic, 68 times more toxic than arsenic, and its toxicity is only second to botulinum. High intake may lead to liver cancer or death, while long-term intake of small doses of aflatoxin may lead to chronic poisoning. The main changes were chronic liver injuries, such as hepatic parenchymal cell degeneration and cirrhosis. A series of symptoms such as growth retardation, weight loss, infertility or fewer offspring occurred in animals.

Long-term consumption of food containing a low concentration of aflatoxin is considered to be the main cause of liver cancer, gastric cancer, intestinal cancer, and other diseases. In 1988, the International Agency for Research on Cancer (IARC) listed aflatoxin B1 as a human carcinogen. Besides, aflatoxin and other pathogenic factors (such as the Hepatitis virus and others have superimposed effects on the induction of human diseases.

Therefore, we must pay attention to the milk powder and milk nutrients, because milk powder is a long-term low-dose intake, although not death, but long-term intake is harmful to the body and has a certain risk of carcinogenesis.


3. Why does aflatoxin exist in milk powder

You may wonder, isn't aflatoxin present in spoiled soybean cereals? Why did it suddenly appear the milk powder? Is it because of the deterioration of milk powder? if you don't eat spoiled milk powder, you won’t intake aflatoxin?

This is not the case. The main source of aflatoxin in milk powder is milk. If dairy cows eat the feed containing aflatoxin B1, aflatoxin B1 will be transformed into aflatoxin M1 in the body of dairy cows, because of the high-temperature resistance of aflatoxin will not eliminate aflatoxin even in the process of milk powder production. This leads to the presence of aflatoxin in milk powder.

The second is in the milk powder production process, the machine cleaning of the cattle company is not finished, organic matter in the machine mildew, thus producing aflatoxin.

dairy cows
dairy cows

4. National standards for aflatoxin in dairy products

China has the highest allowable content of aflatoxin of milk and its products (sterilized milk, fresh raw milk, whole milk powder, evaporated milk, sweet condensed milk) and butter fresh pig tissue (liver, kidney, blood, and lean meat) is 0.5 g/kg (aflatoxin M1).

The relevant laws of the Federal Government of the United States stipulate that the content of aflatoxin in human consumption food, milk powder recipes and dairy cattle feed (referring to the total amount of B1+B2+G1+G2) cannot exceed 15 ug/kg. The content of milk consumed by human beings cannot exceed 0.5 ug/kg, and the content of other animal feed cannot exceed 300 ug/kg.

The EU countries stipulate more stringent restrictions on aflatoxin B1 in peanuts and nuts, processed products and all cereals and processed products; M1 in raw cow milk, heat-treated milk, and processed milk products is 0.050 ug/kg; M1 in infant food (including infant milk) is 0.025 ug/kg.

5. How to detect and eliminate aflatoxin?

Aflatoxin is good at judging the deterioration of legumes and cereals, as long as they observe if there is deterioration of legumes and cereals. But it is difficult to judge in some processed foods of legumes and cereals. Needless to say, in milk and milk powder, it is difficult to judge whether the food contains aflatoxin by naked eyes or even by the mouth. There are several methods to detect aflatoxin: thin-layer chromatography, liquid chromatography, immunochemical analysis, HPLC, and aflatoxin test paper.

The test paper is the fastest and most convenient. The aflatoxin rapid test paper can be used for the qualitative determination of aflatoxin in samples in 5-10 minutes. The aflatoxin standard sample method can be used to estimate the content of aflatoxin, which is very suitable for field testing and preliminary selection of numerous samples.

Aflatoxin is resistant to high temperatures and acid. It can not be destroyed by cooking temperature. The pyrolysis temperature is 280 C. So what can be done to degrade aflatoxin? Aflatoxin in edible oil is better degraded, while aflatoxin M1 in milk powder is more difficult to reduce.

Fortunately, the incidence of aflatoxin in milk powder is relatively low. When choosing milk powder, we should focus on the source of fresh milk and try to choose milk powder from natural pasture. Organic is the best, but the corresponding price may be more expensive. If you are not sure, milk powder can also be bought back and tested by yourself.

milk powder
milk powder