Different forms of fungi, present in an unsuitable environment at any stage of food /feed production and consumption chain lead to unwanted changes and decompositions. With the rise of the humidity and depending on favorable temperature especially in grain, oilseeds, fodder and other dried food, micro fungi known as mold propagate and thus produce poisonous toxic substances or mold poisons. Mold spores are propagated and disseminated under appropriate temperature, storage conditions, humidity, physical deformation and grow as canker. Almost all dry fruits, spices, cotton seeds, milk products and feeds stored under inappropriate conditions of temperature and humidity are at risk to grow aflatoxins.  Aflatoxin is metabolized within the body of the animals who consumed the feed messed up by aflatoxins. It passes indirectly to people who eat these products.  The primary condition for formation of aflatoxins in foodstuff is its becoming infected by the spores of the mold, and the secondary one is infested foodstuff itself. To prevent aflatoxin formation it is necessary to implement advanced agricultural techniques. Fertilization and irrigation should be done in a way according to the soil and crop. It is immediately after its harvest that the product should be dried up appropriately as recommended by experts. Drying work by laying outdoors should be replaced by modern facilities. Convenient storage conditions can prevent the emergence of aflatoxin to a great extent.