Mycotoxins are highly toxic chemicals produced under some environmental conditions by a number of fungi. When growing crops in a field it is inevitable that the crop will be exposed to the fungi that produce mycotoxin but the toxins are only made if the crop happens to be affected by specific weather conditions so most crops are not effected while others can be heavily affected.
To counter the potential health problem if these toxins get into the food chain the EU sets strict limits to the amount permitted in food for humans and guidelines for animal feed and implements strict testing procedures to identify affected batches of grain.
More recently new countries have entered the EU with their own regulations and some countries have been arguing for even lower limits to permitted levels of mycotoxin, despite there being no evidence to suggest that existing permitted levels are toxic to humans.
The snag is that this is a careful balancing act between mycotoxin levels and farmer's incomes. As soon as a harvested crop is declared to have too much mycotoxin its monetary value drops. Therefore as soon as the EU reduces the permitted levels of mycotoxin in a crop there will be crops that will suddenly be worth less, even though the farmer has not changed how he grows the crop. The levels of mycotoxin vary according to weather conditions and thus tend to affect some countries more than others.
This news article features a representative of EU farmers resisting pressure on the EU to reduce permitted levels of some mycotoxins as this will cost their members money while at the same time having no apparent justification based on known health risks - perhaps this is part of a long term drive to reduce toxin levels in our food as far as is possible & feasible?
NOTE: Farmers Guardian article on same issue