Food Safety and Regulatory Measures

Biography

Biography: Akos Mesterhazy

Abstract

The most important food safety risks in cereals are caused by toxigenic fungi. The general experience is that high toxin contamination closely connected to susceptible cultivars. As most cultivars in common production are susceptible, it depends mostly on the weather the outbreak and severity of the epidemic and the toxin contamination. The resistance screenings in wheat verified this experience. Therefore, the question was how far the disease resistance determines toxin contamination. Thousands of commercial cultivars, and breeding lines from FHB program were tested in the past decades. The best trait to signalize deoxynivalenol (DON) reaction is the rate of Fusarium damaged kernels (FDK). Ten to 20 times differences between genotype occur regularly. The resistance to the different Fusarium spp. is the same, QTLs are species-neutral, the breeding against F. graminearum determines resistance also to the other Fusarium species. The correlation between FDK and DON is normally above r=0.80 in experimental series, indicating the decisive role of the resistance in the control of toxin contamination. However, there were found genotypes with DON overproduction and DON resistance, but their significance is of secondary importance. In maize the situation is similar, but it is more complicated. The resistance against the three main pathogens F. graminearum, F. verticillioides and Aspergillus flavus agrees seldom, in most hybrids they diverge. The genetic background is unknown. Here the agreement between infection severity and toxin contamination is more variable, larger ± differences occur in toxin overproduction and resistance than in wheat. However, the genotypes can be identified with lower risk in production. There are genotypes that have 2-4 times higher toxin contamination than others at the same infection severity. For this reason without toxin measurements no food safety risk assessment is possible. To this we need well planned tests with artificial inoculations with at least two different isolates of the given pathogens. The cultivar resistance differences are very large, 10 times or higher, so a regular screening advises us to choose the more resistant hybrids for commercial production. The lesson is the preventing of the toxin contamination is mainly the increase of the resistance. When we do not control it, under epidemic conditions the toxin contamination can be so high that its control will be impossible. Fungicides control with improved technology may give 70-80 % DON reduction in wheat. We have in Hungary medium resistant cultivars in commercial production that can be harvested with a fungicide preventive control so that no additional cleaning and other means are necessary in order to secure the food safety standard. The maize is more complicated, the fungicide protection is yet in experimental phase, guaranteed technology does not yet exists. Therefore the role of resistance is even higher. The detoxification is expensive, if works at all. Separation of FDK kernels is working in wheat in milling plants, but it increases costs and decreases yield. As ecological and epidemic risk conditions are different, the needed resistance level can be different in different continents and regions. Therefore, to secure food safety the preference of the more resistant genotypes is the key at cultivar registration test. When this required, the breeding firms should adapt to the new requirements and breed more resistant cultivars. Of course, agronomy should updated to provide efficient integrated plant management.