Researchers develop screening method to find mycotoxins in raw wheat
By Joe Whitworth on June 20, 2019
Scientists have developed a method to detect two types of mycotoxins in wheat products.
Researchers from the European Commission’s Joint Research Centre (JRC) and CNR-National Council of Italy developed the method based on infrared spectroscopy to find Deoxynivalenol (DON) in wheat bran and Ochratoxin A (OTA) in durum wheat. Research on DON was published in the Journal of the Science of Food and Agriculture. The work on OTA is published in the Food Chemistry journal.
Wheat is the most consumed cereal worldwide and Europeans are among the highest per-capita consumers. It can be found in bread, pasta, breakfast cereals, biscuits, cookies, pie crusts and cakes. Some mycotoxins are deactivated by cooking, others are not, according to information from the U.S. National Institutes for Health. For example, previous reviews by other researchers on DON showed only 50 percent of samples were susceptible to heat. Another study showed cooking or heat treatment had almost no impact on DON.
Scale and effect of DON and OTA
Wheat and cereals are susceptible to fungal colonization in the field and during storage. This can lead to contamination of grains with mycotoxins, which are natural toxins produced by certain molds that can cause food poisoning.
Deoxynivalenol can trigger vomiting, reduced weight gain, diarrhea, skin lesions, growth depression and immunosuppression to humans and animals. Ochratoxin A has been classified as a possible human carcinogen by the International Agency for Research on Cancer.
DON is the most common mycotoxin in wheat, maize, barley, oats and rye, from phytopathogenic Fusarium species. Wheat bran is the part of the grain with the highest concentration. OTA is produced by several species of the genera Aspergillus and Penicillium and often found in cereals.
EU control laboratories check food for these substances, but applied methods are time-consuming and expensive. The method are expected to help official controls to ensure wheat products are safe for consumption.
Christoph von Holst, a JRC scientist, said legal limits have been set for both mycotoxins in cereal-based food products to protect consumers in the European Union.
“We need to further improve the efficiency of this monitoring. There is a need for rapid detection methods. This alternative technique is fast, not expensive and easy to use. It can further improve the efficiency of the control activities.”
The EU legal limit for DON in cereals is 750 µg/kg and 5 µg/kg for unprocessed cereals, 3 µg/kg for products from unprocessed cereals and 0.5 µg/kg for processed cereals based foods.
Mycotoxin reference material
Meanwhile, scientists at the National Institute of Standards and Technology (NIST) have developed a reference material that can be used to identify toxins in corn products.Known as Standard Reference Material (SRM) 1565, it will be sold from July and can be used by labs who need to measure corn for compounds produced by mold, known as mycotoxins. The SRM can identify 12 mycotoxins that occur in corn crops and products. The work was published in the Journal of AOAC Internationa
Researchers said it addresses the increasing needs of labs moving toward liquid chromatography- mass spectrometry (LC-MS)-based multi-mycotoxin analysis. Reference materials for mycotoxins are already available from a variety of producers but they mainly address a single mycotoxin or group of mycotoxins. Melissa Phillips, team leader, said as the reference material can be used to check for different types of mycotoxins, labs can do more testing in a shorter time.
“In all economies, people want to be able to examine the crops they’ve grown. People want to be confident in the safety of their food.”
To make the material, Phillips and her team, including the U.S. Food and Drug Administration, gathered corn products from sources including regional labs and grocery stores. They blended together contaminated samples with uncontaminated products to produce a powdered SRM that has levels of mycotoxins equal to regulatory limits already in place. The food safety research team at NIST plan to develop SRMs for mycotoxins in other products.
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