The challenge of mycotoxins

Abstract

Mycotoxins are fungal metabolites which, when ingested, inhaled or absorbed through the skin, cause lowered performance, sickness or death in man or animals, including birds" (Pitt, 1996). They are poisonous substances, which occur naturally and are perhaps the most prevalent source of food related health risk in field crops. However, they are almost unrecognized publicly. Consumption of food with high levels can be fatal. Long-term exposure can, amongst other things, increase cancer risk and suppress the immune system. An invaluable web site http://www.inchem.org is available as "a means of rapid access to internationally peer reviewed information on chemicals commonly used throughout the world, which may also occur as contaminants in the environment and food". Mycotoxins are a significant component of the site and should be consulted for further information. Filamentous fungi are ubiquitous in nature and responsible for producing mycotoxins in agricultural crops. The fungi and mycotoxins are considered generally as being natural and unavoidable. It is accepted that St Anthony's fire (Holy fire), a disease that affected many parts of Europe in the tenth century, was caused by the consumption of rye contaminated with ergot alkaloids, a known mycotoxin of Claviceps purpurea (CAST, 2003). Mycotoxins have plagued mankind before and since the beginning of organized crop production, i.e. always. They attract worldwide scientific, political and economic attention because of the significant economic losses associated with impacts on human health, animal productivity and international trade. Unfortunately, they are also considered as potential weapons and so could enter the food chain by this route. A recent report (CAST, 2003) has a wealth of information regarding mycotoxins, and has been referred to liberally in this overview. It is also available on the World Wide Web. Food contamination with mycotoxins has only been fully appreciated since the 1960's, when an unknown disease of animals occurred in England (CAST, 2003). Over 100 000 turkeys and a large number of ducks and pheasants died. After a huge research effort, a toxic compound produced by the microscopic fungus Aspergillus flavus was discovered in the feeds and was named aflatoxin after the fungus. It is currently thought that many diseases have been caused by mycotoxins (Table 1). Indeed, the consumption of foods with high levels of certain mycotoxins can cause severe illness characterised by vomiting, abdominal pains, pulmonary oedema, convulsions, coma, and (rarely) death. Notable outbreaks were the death of 3 people in Taiwan in 1967 and 100 people in India in 1974, from aflatoxin in rice and corn respectively. Of equal or even greater importance, are long term effects particularly cancer and immune deficiency. Aflatoxins are of particular concern in populations with high levels of hepatitis B as they are shown to be 60 times higher when people have been exposed to the metabolite. The impact of mycotoxins on human and animal health is now recognized and it is estimated that they cause high economic losses. For example, the annual cost in the US alone was estimated as US$1.4 billion (CAST, 2003). The field of mycotoxins is complex and interdisciplinary. It involves 5 interrelated systems (Paterson et al. 2004): - commodity system consists of all aspects of production, marketing, and utilisation; - spoilage system has many interrelated factors, e.g. biological, chemical, physical, micro- and macro-environmental; - mycotoxin system involves 5 subsystems -productivity, metabolism, toxicology, health and wealth; - control system comprises prevention, mycotoxin analysis and segregation of contaminated material, and detoxification. A hazard analysis and critical control points (HACCP) approach is considered the optimal system for control; and - socio-economic system described as cultural, political and economic. © 2007 Springer Science+Business Media, LLC.