[Dioxins: risk management by agriculture and feed industry--options and limits].

Dioxins represent a group of undesired substances that may contaminate feedstuffs. Due to their persistency in the environment it can be expected that feed contamination by dioxins will occur in the future, too. Therefore efforts in agriculture and in the feed industry have to be focussed on measures that minimize the dioxin contamination of feedstuffs, especially under the aspects of food safety. Several dioxin scandals in the past have contributed to a higher awareness in feed production as well as on the side of food consumers and administration resulting in changes of feed legislation (implementation of maximum levels of dioxins in feed and food). Some of the dioxin scandals enlarged the knowledge concerning the potential ways dioxins entering the food chain (for example dioxin contamination during the drying process of grass meal, recycling of contaminated oils, use of contaminated kaolinit a.s.o.). In difference to those accidents in feed producing agriculture there is a main influence of potential soil contamination on the dioxin contents in feedstuffs (like roughage). Producing roughage (green fodder, silage, hay) on areas with grass land by grazing animals can result in corresponding consumption of soil that contaminates the green fodder. Intending a lowest feed contamination by dioxins implies that the soil contamination is known. Depending on the rate of soil contamination farmers should decide on the kind of feed production and on the techniques of harvesting the fodder. For example it is possible to produce maize (whole plant in high cut technique) without higher dioxin contents in maize silage, on the other hand it can not be recommended to use contaminated fields for growing beets or by grazing ruminants, pigs or poultry (outdoor systems). In general during the harvesting process technical measures have to be chosen that reduce/minimize the soil contamination because the dioxin concentration in the soil of exposed areas is much more higher than the dioxin concentration within the feedstuffs. The high costs of dioxin analyses limit an implementation of a monitoring program including samples of soil and feedstuffs of each feed producing unit or individual farms. Therefore it is necessary to focus the monitoring efforts on areas and samples that let expect a higher risk of dioxin contamination. New screening tests should be developed and implemented that allow a higher frequency and density of control measures concerning dioxin. In the case of suspicious findings only those samples could be analysed by the classic chemical procedure (time consuming, high costs). Especially in cases of food contamination (for example detected in monitoring programs of the food industry) it is necessary to find out the way and cause, not neglecting the potential role of the contaminated soil. Last but not least it is recommended to inform the public continuously about levels of dioxins that are actually found in food as well as in feed (and soils), especially on behalf of the consumers confidence in food and feed control and its related administration. Continuous information will increase the consumers understanding that there is (and will be for further years) a background contamination of feed and food in general (that decreased markedly in the last decades), and that cases of detected higher dioxin levels are exceptional findings that result immediately in efforts of the food and feed industry to obstruct the way that enabled an entering to the food chain.