5,7, Alltech Mycotoxins

International Food Hygiene — Volume 19 Number 2 5 Mycotoxins are harmful metabolites of moulds (fungi) that can be synthesised on plant materials pre-harvest. Mycotoxins can also accumulate when plant products are stored under suboptimal conditions. Formation of mycotoxins in the field will depend on climatic conditions at the time of harvest and during critical stages of plant development. High moisture content is often a key promoter of fungal growth and mycotoxin production, but drought conditions can also promote mycotoxin contamination of grains as a result of environmental stressors on the fungi. Foods of plant origin present the greatest chance of human exposure to mycotoxins. Lower quality grains and nuts are typically diverted to the animal feed chain, while higher quality plant materials, which have lower levels of contamination, are normally used as human foods. Numerous processing techniques can also be employed to further reduce mycotoxin concentrations in foods of plant origin. Foods of animal origin usually present a lesser threat to human health. Ruminant animals including cattle, sheep and goats are protected to some degree from the harmful effects of feedborne mycotoxins due to the detoxifying actions of rumen micro-organisms. This usually results in vanishingly low residues of mycotoxins and metabolites in meat products. Milk, however, is monitored for the carcinogenic mycotoxin metabolite aflatoxin M1. Monogastric animals such as pigs and avian species, including broiler chickens, laying hens and turkeys, are more sensitive than ruminants to the effects of feedborne mycotoxins but there is still considerable potential for mycotoxin degradation which minimises harmful residues in pork, poultry meat and eggs. Residues of the carcinogenic mycotoxin ochratoxin A, however, are monitored in certain pork products.