Mycotoxins   
 

• What are mycotoxins?
   

• Why are mycotoxins important?
   

• When are mycotoxins produced?
   

• Foods affected by mycotoxins
   

• Factors affecting mycotoxin production
   

• Health implications
   

• Detection of mycotoxins
   

• Prevention and control
   

• Regulations and guidelines
   

• Related links
   

• References

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Adapted from Calvo, 2005.

Factors affecting mycotoxin production
 

Most mould is naturally occurring and is found in soil and air.  It is difficult to prevent contact with agriculture commodities. However, the factors that affect growth and toxin production may be controlled.

Most mycotoxins are very stable. They can resist high temperatures and several manufacturing processes. For example, zearalenone is stable during storage, milling and cooking (Gajecki, 2002). DON and T-2 toxin are stable at 120°C and relatively stable at 180°C (Kamimura, 1989). Although, cooking can reduce the levels of certain mycotoxins in food products, it does not achieve complete detoxification. It is not surprising to detect low content of mycotoxins in processed foods. This is why it is important to prevent the formation of toxins in raw material.

Health implications

Mycotoxins can cause different toxic effects depending on the type of toxin and the dosage. High doses of mycotoxin can cause acute illness or death; low doses cause chronic toxicity. The toxicity of mycotoxins may affect the body’s nervous, heart, lungs and digestive tract. Mycotoxins are also associated with acute hepatitis and liver cancer.

Detection

Food products need to be tested for mycotoxins:

• to meet regulatory guidelines
• to reduce the risks of mycotoxin contamination
• to maintain product quality

Mycotoxins cannot be detected visually, have no specific taste or smell in contaminated food. This makes it difficult to identify an infected crop. Analytical tests are the main tool for toxin detection. Table 3 indicates some of the available tests.

Table 3. Methods for detection of mycotoxins

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ELISA, enzyme-linked immunosorbent assays

TLC, thin-layer chromatography

HPLC, high-performance liquid chromatography

GC, gas chromatography

LC, liquid chromatography

MS, mass spectrometry

FILIA, flow-injection liposome immunoanalysis

ELISA test kits are commercially available (ex: R-Biopharm, Biotrace International, Neogen Corporation, Elisa Technologies). A list of these suppliers is provided in the Analytical testing supplier section.

More information on mycotoxin testing can be found in the Aflatoxin Handbook developed by the Federal Grain Inspection Service (USDA).

Prevention and control

Mycotoxins are difficult, and sometimes impossible to eliminate. The best control is prevention. The production can be prevented by reducing the moisture content of food products and controlling storage conditions such as temperature and/or relative humidity. In general, reducing moisture content to the equivalent of less than 0.70 water activity (<14.5% moisture by weight) prevents mould growth and mycotoxins.

The Canadian Food Inspection Agency (CFIA) recommends the following management practices to minimize mycotoxin contamination:

• Limit bird and insect damage. Damaged kernels are easily contaminated with mould.
• Harvest grain as soon as possible to reduce high moisture conditions. Mould grows better under high moisture environment.
• Dry grain. Low moisture conditions prevent mould growth and mycotoxin production post-harvest.
• Ensure silo conditions remain oxygen free (anaerobic conditions) to limit mould growth and mycotoxin contamination. Mould cannot grow under truly anaerobic conditions.
• Use crop rotation to minimize the carry-over of moulds from one year to the next.
• Avoid planting crops that may be susceptible to mould adjacent fields where the disease may spread from one crop to the other.
• Grain handlers should use masks to avoid inhalation and ingestion of dust. Mould spores and mycotoxins are often concentrated in the fines and dust of grains.

Hazard Analysis Critical Control Point (HACCP) offers a suitable approach to control mycotoxins by preventing their formation. The Manual on the Application of the HACCP System in Mycotoxin Prevention and Control, published by FAO in 2001, provides an overview and examples on the application of HACCP to mycotoxin control.

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Regulations and guidelines

Currently, more than 100 countries have mycotoxin regulations for food and/or feed. Canada and the United States have had mycotoxin regulations in place for many years. Recommended tolerances for several mycotoxins can be found on the CFIA website at: inspection.gc.ca/english/anima/feebet/pol/mycoe.shtml.

For more information on worldwide regulations, see FAO publication Worldwide Regulations for Mycotoxins in Food and Feed in 2003

Related links

CFIA Mycotoxins Fact Sheet (CFIA)

Manual on the Application of the HACCP System in Mycotoxin Prevention and Control (FAO)

HACCP - Prevention and Control of Mycotoxins (European Mycotoxin Awareness Network)

Worldwide Regulations for Mycotoxins in Food and Feed in 2003 (FAO)

Aflatoxin handbook – Federal Grain Inspection Service (USDA)

Fusarium in Wheat and Barley (Agriculture and Agri-Food Canada)

References

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For information on the Food Safety Program contact the CVO/Food Safety Knowledge Centre.  For technical information, call 204-795-7968 in Winnipeg; or e-mail foodsafety@gov.mb.ca. For general information, contact your local GO Centre.