Aflatoxin Testing & Exposure

Instructor: Artem Cheprasov

Artem has a doctor of veterinary medicine degree.

Aflatoxins can be really dangerous. Because of the threat they pose to human health, it's important you know how people may be exposed to these toxins and how we test for their presence.

Food Poisoning By Toxin

When it comes to eating abroad in many places, what do you have to worry about most? It's food poisoning. The biggest culprits are usually microscopic entities like viruses and bacteria that will give you a bad case of the runs for a couple of days, not to mention some vomiting.

But there's another thing that you need to be concerned about. It's also microscopic but it's not a living entity. It's called aflatoxin, a toxin produced by a mold fungus. If this fungus grows on edible substances like corn, peanuts, and tree nuts, it may produce aflatoxins. Those toxins may then be accidentally eaten by a person and this can result in a deadly case of aflatoxicosis, or poisoning via aflatoxin.

Many countries thus screen and test for aflatoxin contamination in their crops in order to prevent exactly that! So, let's find out more about how people may be exposed to aflatoxin and how aflatoxin can be tested for.

Aflatoxin Exposure

Aflatoxin can contaminate crops even prior to harvest. It can also contaminate crops after harvest if the crop isn't properly dried after collection or if it's stored after drying in such a way that too much moisture seeps into the stored goods, so much that mold growth can occur.

People are thus exposed to aflatoxin when they consume crops contaminated with it. This more commonly includes the following commodities:

  • Corn
  • Peanuts
  • Cottonseed

However, it can also include a lot of other foods, such as:

  • Tree nuts
  • Wheat
  • Barley
  • Oats
  • Sweet potatoes and potatoes
  • Sorghum
  • Rice
  • Various beans
  • Figs
  • Spices, such as cayenne pepper

Aflatoxins may also be found in dairy products like milk, cheese, and yogurt, as well as meat products. The dairy products and meat are probably contaminated with aflatoxins not because the mold fungus grows on these products as it would on crops, but because the animals may have eaten feed that is contaminated with the aflatoxins.

However, some styles of meat products, like certain sausages, are actually mold ripened and this opens up the possibility that dangerous mold fungi, including aflatoxin-producing ones, may grow and contaminate the meat product directly.

Aflatoxin Testing

Because aflatoxins can pose a serious danger to human health, including liver cancer and death, it makes sense that our food supply be tested for them. There are numerous ways by which aflatoxin can be tested for depending on the circumstances and food in question.

One of them involves using a black light (an ultraviolet light) to visually inspect for the presence of aflatoxins. If aflatoxins are present, they may glow the color of a firefly, a gold fluorescent color. However, it's critical to note that the presence of this glow may be attributable to other things, and the absence of this glow does not guarantee the absence of aflatoxins. More scientific means of testing for aflatoxin must be employed to ensure there is none present.

This includes on-site testing, such as directly at a farm, which may be accomplished with scientific commercial kits. These kits use immunoassay techniques to determine the presence of aflatoxins. Immunoassay techniques detect aflatoxins through the use of biological molecules. Unlike the blacklight technique, these kits are very good at testing specifically for aflatoxins. However, the test results may need to be confirmed via laboratory analysis as user error in the preparation of the sample for use with these kits may render the test results inaccurate.

Laboratory techniques are the most accurate ways by which aflatoxins can be tested for and they include three main steps:

1. Extraction of the aflatoxin from the food sample. This can be done with a substance like methanol (wood alcohol) mixed with water.

2. Purification and concentration of the aflatoxin via a technique such as immunoaffinity column chromatography, which separates the aflatoxin from other compounds using biological molecules.

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