Safety Of Food And Recent Aflatoxin Scare In Europe

Europe was hit by a new series of food safety scandals this year. The findings that battery eggs in Germany were labeled as organic and horse meet was sold as beef didn't help to improve the trust in the mind of customers that EU is capable of controlling the food safety on the continent.

One particular food safety scare also created a certain degree of confusion among the public. Multiple newspaper reports in March this year were talking about a new danger – aflatoxin. Tons of milk in Germany were contaminated with this carcinogenic toxin. The source of troubles was traced to the contaminated maize from Serbia which was used as animal feed.

Many people have never heard of the word “aflatoxin” before. This is why it does make sense to have a closer look on this problem.

What is Aflatoxin?

Cereal crops are vulnerable to the attacks by infectious agents such as fungi that produce toxins. Among these toxins, Aflatoxin is of great significance due to its deleterious effects on poultry, livestock, as well as humans. The name aflatoxin refers to the group of four toxins (B1, B2, G1, G2) produced by fungi that belong to the Aspergillus family. They were discovered in 1960 during outbreak of Turkey X syndrome disease in the UK. It was found that the cause of this disease was a toxin produced by a fungus Aspergillus flavus and the toxin was given the name aflatoxin.

Some of the foods that have higher risk of contamination with aflatoxin are peanuts, tree nuts such as pecans, corn and wheat. Even tobacco is a target of this fungus. There is an opinion that many of tobacco associated malignancies might have a positive relationship with aflatoxin. Aflatoxin might be present in the animal products such as milk when animals are fed on the contaminated foods.

Why aflatoxin is so dangerous?

Aflatoxin contamination of the crops is considered one of the major problems of the food safety in the EU. As a result, aflatoxin is one of the most intensively studied mycotoxins in the world.

Hepatocellular carcinoma is one of the most common malignancies in China. About 45% of all hepatocellular carcinoma cases worldwide are registered in China. This high incidence has been attributed to the consumption of aflatoxin contaminated food.

Aflatoxin also has other negative effects on human health. It suppresses the immune system of the body and retards the growth and development of young children.

Mechanism of action: how aflatoxin causes cancer?

Aflatoxin is a carcinogen, the compound causing cancer. The problem is that aflatoxin is one of the strongest carcinogens known. This means that even the low dose exposure to this toxin can cause the development of this disease.

Aflatoxin belongs to the class of so-called DNA intercalators. The molecule has a planar structure which is capable of inserting itself inside the DNA helix. Once it is there, aflatoxin chemically reacts with DNA components and thus promotes the generation of mutations, the changes in DNA native sequence. When mutations happen in the genes responsible for the control of cellular growth and division, they can lead to the development of cancer.

The most likely place where the tumor can develop in human body due to aflatoxin is liver. Liver cells have higher exposure to aflatoxin, and the toxin can be easily taken up by them.

Aflatoxin in the food: what is the safe level?

Different countries have different regulations in regards of allowed aflatoxin level. According to the US Foods and Drug Administration, the maximum level of total aflatoxins in human food should not exceed 20 microgram per kilogram. There is an exception of milk which has the maximum level of 0.5 microgram per kilogram. Aflatoxin in milk is considered more dangerous. The maximum level for most of the animal feeds is also 20 µg/kg.

It’s interesting to note that in response to the latest aflatoxin scare, Serbian government reacted by simply increasing the maximum permitted level of aflatoxins in the food above the European standards. Looks like easiest solution to the problem, isn’t it?

Why aflatoxin contamination is so difficult to control?

One of the reasons aflatoxin contamination is so difficult to control is the way the fungus contaminates the crops. Some pockets of plants might be heavily contaminated while the rest may look completely normal. It is impossible to analyze each and every single plant out there in the field. Instead, the estimates of the overall conditions of crop are made by checking the randomly selected samples. This could be misleading: heavily contaminated plants can be missed easily by this method.

Inadequate post-harvest storage conditions, such as elevated humidity and temperature may accelerate the fungal growth and thus contribute to the increase of aflatoxin level after the harvest.

Insects damage crops, and aflatoxin producing fungus grows rapidly on the damaged plants. If insecticides are not sprayed on time the chance of aflatoxin contamination increases.

Prevention of aflatoxin contamination

Many different strategies have been developed to control the aflatoxin contamination. These strategies are applied at different stages of crop production and processing.

Crops are altered genetically in such a way that they can no longer be affected by fungi. Therefore, the risk of aflatoxin contamination can be reduced by this technique.

Insecticides use should be encouraged in places where aflatoxin contamination is common. This will reduce the risk of plant infection with opportunistic pathogens.

Crops should be stored in clean places to avoid any contamination with the toxin producing fungus. Moisture level of the storage environment should be regularly monitored and mechanical driers should be used if needed.

Finally, the transportation of the crops should be done it the containers which are dry, clean and free of any fungal growth.

Aflatoxin contamination of the crops and food products poses problems both for the human health and economy. However by using the adequate preventive measures the risk of contamination can be greatly reduced.