Understanding Mycotoxins
by Vicki Hershey of Mars Horsecare US
Mycotoxins are toxin compounds produced by fungi such as molds. Very often molds are visible, however, the visual absence of mold, does not mean Mycotoxins are not present. Many are microscopic. The right conditions for growth include temperature, oxygen and moisture. These conditions increase the likelihood that fungi will be present in small grains. High moisture levels in grain encourage fungal growth, while the cool temperatures increase the production of Mycotoxins. Temperature treatments, such as cooking and freezing, do not destroy these mycotoxins. Secondly, grains are often stored in grain bins where little or no aeration or re-circulation occurs. The three most common Mycotoxins that could be present in grains received are, aflatoxin, deoxynivaleno or DON, and fumonison. However, these Mycotoxins are not limited to grain, and can also be present in hay, grass or silage.
Aflatoxins (Aspergillus flavus) affect a number of crops predominately corn. It can also be present in: wheat, midds, barley and rice. Typically, it has a yellow green appearance when growing on kernels. Chances of growth increase during hot dry weather. Its presence is greater in grain that is produced under stress conditions such as drought, heat, insect infestation, and fertilizer stress. Management practices such as irrigation, good insect control and timely fertilization may reduce stress and reduce chances of aflatoxin levels. Aflatoxin levels are regulated by the Food and Drug Administration (FDA) Levels must not exceed 20 ppb (parts per billion)
Fumonison Fusarium moniliforme (Fusarium verticillioides) is a group of Mycotoxins that are common pathogens of corn and possibly rice. It is so common in fact, that it is found wherever corn is grown. It can appear white to salmon colored. Fumonison have been implicated as a possible cause of equine leukoencephalomalacia (ELEM), a serious disease in horses, and porcine edema – a disease in swine. Poultry and cattle are not especially susceptible to fumonison. Fumonison levels are regulated by the Food and Drug Administration (FDA) and must not exceed 5 ppm (parts per million)
Vomitoxin or DON are Mycotoxins produced by certain species of Fusarium, the most important of which is F. graminearum (Gibberella zeae). This fungus causes Gibberella ear (also known as red ear rot) or stalk rot on corn and head scab in wheat, possibly found in midds, barley and oats. The fungus itself appears reddish to pinkish. The fungus may cause a reddish discoloration of the cob and kernels. Disease tends to be worse when corn is grown without crop rotation or after wheat as this pathogen also infects wheat. It may be worse when corn is grown in no till situations. FDA has recommended that total feed levels of DON not exceed 5 ppm (parts per million).
The United States Department of Agriculture (USDA) along with the Food and Drug Administration (FDA) have provided education on Mycotoxins management in the field with better farming practices and improved crop plants with greater resistance to insect damage and fungal infection that leads to Mycotoxins production. Mycotoxins management and education continues with improved harvesting practices, and better storage conditions.
Using both science and common sense as guidelines, feed-producing facilities can develop and implement strict quality control programs and good manufacturing practices (GMP’s) to reduce and eliminate the risk if Mycotoxins being introduced into their facilities. However, they must be committed to making sure these programs and GMP’s are followed by; educating associates, monitoring processes and providing documentation to ensure traceability in case of accidental or intentional contamination to the feed chain. By following these guidelines, and implementing these programs, we can protect our facilities, and the animals we feed.
