*5.4. Mycotoxin Contamination*

Mycotoxins are toxic chemicals unsuitable for animal feed and human consumption. High concentrations of aflatoxin can pose a serious health risk both to humans and livestock. A significant concentration of toxin levels is frequently measured even during harvest, leading to the need for control measures, both pre- and post-harvest. The most important source of the mycotoxin problem is the generally high susceptibility of the grain crops. Large toxin epidemics in the fields are always consequences of an epidemic. WHO estimated that 25% of the world's crops are contaminated by mycotoxins excluding considerable preharvest losses [69]. Up to 25–40% of global

cereal grains are contaminated by the mycotoxins produced by fungi Kumar et al. [70]. Dowling [71] reported, based on UNO and FAO data, that 25% of the world grain crop is significantly contaminated by mycotoxins.

McMullen et al. [72] reported that due to nearly yearly epidemics in the USA the acreage of wheat was reduced from 29 million ha (1992) to 21.4 million ha (2010). The same numbers for barley are 2.9 and 1.0 million ha. This is normally not taken into consideration. The high toxin contamination of harvested yield caused additional quality loss and a reduction in prices of 50–90%. The yield and quality losses amounted to billions of dollars. Similar losses were also recorded in epidemic years in Canada, Europe, and China. Maize is a more complicated problem. Szabo et al. [73] estimated losses in maize in 2014 at about 300 million dollars, with nearly no yield reduction. The contaminated grain (deoxynivalenol, zearalenone, fumonisins) decreased the price of harvested grain by about \$32 USD/t or 25%, while the rest of the loss was attributed to animal husbandry by lower weight gain, sexual disorders, higher death rates, cost of toxin bindings and antibiotics, etc.

This means that yield loss on its own does not show the significance of the problem. The damage caused by toxins during storage represents about 10% yearly loss at a conservative estimation and removes 210 mt of grain per annum globally. This amount represents stored grains and does not include the infected and light grain part in small grains blown out by the combine at harvest, which cannot be measured, but exists. Due to toxin regulations the human population is well protected in the developed world, but this is not the case in many countries where animal husbandry the situation is similar—contaminated grains are normally used in animal husbandry In small grains cleaning systems, optical selection of infected grains can reduce toxin levels, but the cost is relatively high equivalent to a yield loss of 10–20%. In maize, however, such e ffective methods are in experimental phase. Most of the toxins are of field origin detectable at harvest, but bad storage conditions can cause significant increases. In order to minimize grain losses, fungi formation must be addressed during storage.
