Strategies to reduce mycotoxin and fungal alkaloid contamination in organic and conventional cereal production systems

Summary

Mycotoxins are toxic metabolites formed by specific fungi that grow on living plants and their residues under favourable conditions. They are undesirable ingredients of food and feed. Risks are also posed by the spores and toxin-contaminated raised dusts. Contamination by mycotoxins is a severe problem in food security. More than 300 species of fungi with the ability to form mycotoxins have been identified. More than 400 metabolites are assigned to the group of mycotoxins. Fortunately, only about 20 mycotoxins produced by five genera of fungi (Fusarium, Penicillium, Claviceps, Alternaria and Aspergillus) are found regularly or periodically in food and feed at levels which might have an impact on human and animal health (Gareis, 1999a).
Since synthetic fungicides are not allowed in Organic Agriculture, fungal populations are often presumed to be higher in this farming system, and a higher frequency of mycotoxin contamination of organic food and feed has frequently been postulated by Tinker (2001). Others argued that omitting fungicides might lead to higher diversification of microbial populations and therefore limit growth of specific mycotoxin producers. There are controversial reports on varying mycotoxin contamination levels of grains produced organically and in mainstream farming (Marx et al., 1995, Berleth et al., 1998, Birzele et al., 2002, Meier et al., 1999, Stähle et al., 1998, Döll et al., 2002).
Thus, the first aim of this contribution is to analyse whether a higher occurence of mould on organically grown crops and, as a result, a higher risk of mycotoxin impact due to specific organic farming as well as low input farming methods is confirmed by the reviewed literature. Secondly, factors that may influence mycotoxin contamination in the different cereal production systems are highlighted. Finally, strategies to reduce mycotoxin contamination are described. The recommendations given are limited to the conditions of the temperate European climate.