The Aspergillus flavus mold is a soil-dwelling fungus with exceptional heat tolerance, found throughout worldwide. When it develops on corn crops, it produces a toxin called aflatoxin, which is dangerous to both humans and animals. The carcinogenic aflatoxin can cause liver disease, heart inflammation, and even cancer, making it crucial to ensure that the harvested corn (whether for feed or food purposes) is free from aflatoxin produced by Aspergillus flavus.
The fungus spreads most readily in conditions of high humidity and temperature, while hot and dry weather exacerbates toxin production. Basically, the production of toxins is a self-defence mechanism of the fungus, triggered mainly by the sudden extreme hot temperatures.
What was previously known as a storage pathogen has increasingly appeared in fields, with Aspergillus molds causing higher levels of toxin contamination in crops. This trend has become more common in recent years due to changes in climate and hot and drought-stricken summers and is expected to continue in the future.
According to Regulation (EU) No. 165/2010, the permissible upper limit of aflatoxin in food is 5 µg/kg (ppb; aflatoxin B1), while in animal feed, the limit is 20 µg/kg (ppb).
How optical sorting can reduce aflatoxin infection?
As with all other field crops, preventing Aspergillus flavus fungal infections is most effectively achieved in the field by using specially treated seeds and more resistant hybrids. However, if the disease has already appeared in the crop, various cleaning processes can significantly reduce the level of contamination. Both mechanical and optical methods can efficiently lower the toxin levels in the harvest to the accepted limits.
The infection may be present on both the outer surface and inside the seed, and significant amounts can also be found on other plant residues and the dust generated during processing. Therefore, these hotspots should receive particular attention during the cleaning processes.
As the above indicates, only a complex cleaning process can achieve toxin levels below the allowable limit.
Traditional mechanical cleaning technologies, such as flat screens, gravity separators, and appropriately designed dust extraction systems, can easily remove broken grains, other plant residues, and seeds whose structure has changed due to infection, making them lighter. However, modern optical sorting equipment also plays a crucial role in achieving final cleanliness.
In most cases, no visible alterations can be observed on the infected seeds with the naked eye. However, if the infection is present on the surface of the seed by the reaction of kojic acid formed by the fungus and a peroxidase enzyme from the seed crates a compound which is glowing greenisg-gold fluorescent under UV (below 365nm) light.
Taking advantage of this phenomenon, MEYER has developed a state-of-the-art UV sorting technology and introduced it the CG.UV sorter series.
CG.UV sorters are using the proven MEYER structure, enhanced with specifically designed UV lighting and camera system, completed with optimized sorting algorithms and AI deep learning technology.
The sorter can eliminate the glowing infected seeds, as well as broken kernels by rejecting them from the product stream using the patented MAGLEV ejector system, significantly decreasing toxin infection in the input material.
The CG.UV sorters are available in two frame sizes, in order to be able to serve the big capacity demands, MEYER has introduced this technology in 8 and 13 chute sorters.
Struggling with aflatoxin infection? Contact us for more details…
