Last week, a media report said that the government of Kenya has issued warnings about a possible outbreak of aflatoxin in contaminated maize.

Aflatoxin is a potent toxin and a very serious health issue in many parts of the developing world. Kenya itself has experienced other outbreaks over the past decade alone. Major outbreaks have also been seen in India, Malaysia and Taiwan over the years.

This mycotoxin is a natural toxin produced as a secondary metabolite to certain strains of the fungus Aspergillus, in particular Aspergillus flavus and Aspergillus parasiticus.

The toxin is then excreted onto plants or pre-processed foods, some intended for human consumption.

Aflatoxins are contaminants of foods intended for people or animals as a result of fungal contamination. The most common foods implicated are cereals like corn, wheat and rice, oilseeds like peanuts and sunflower, and spices. However, the toxin can affect a very wide range of food stuffs (see below).

Different factors contribute to aflatoxin contamination. In semi-arid climates, the effect of drought can increase the amount of Aspergillus in the air causing pre-harvest contamination of certain crops.

Crops grown and stored in more tropical environments where the temperature and humidity is high usually have a higher risk of both pre and post-harvest contamination. Of course, much of the problem lies with homegrown crops that are not harvested or stored properly.

Aflatoxin poisoning can be broken up into acute and chronic disease depending on the amount of toxin ingested. When people (or animals) ingest aflatoxin contaminated foods, the liver is the main target for disease.

There is a direct link between aflatoxin poisoning and liver cancer. Liver cancer or hepatocellular carcinoma is an important public health concern in many parts of the world due to aflatoxin. According to the CDC, in Kenya, acute aflatoxin poisoning results in liver failure and death in up to 40% of cases.

Besides the obvious health risks, there is the massive economic loss that occurs in parts of the world that can’t afford it.

Prevention and control of aflatoxin in developing countries is mainly focused on good agricultural practices.

Because it is impossible to completely eliminate this danger, in the United States feeds and grains are laboratory tested for levels of aflatoxins and food with unacceptable levels are removed from the market.

Foods most commonly affected by aflatoxins (from the USDA’s Food Safety Research Information Office):

• Cereals (maize, corn, sorghum, pearl millet, rice, wheat)
• Oilseeds (peanut, soybean, sunflower, cotton)
• Spices (chillies, black pepper, coriander, turmeric, ginger)
• Tree nuts (almonds, pistachio, walnuts, coconut)
• Dried fruits (sultanas, figs)
• Cocoa beans
• Milk, eggs, and meat products*

* Milk, eggs, and meat products are occasionally contaminated due to the consumption of aflatoxin-contaminated feed by animals.