On-farm contamination of animals with chemical contaminants.

Food products should not contain unsafe levels of chemical contaminants. However, it is not possible to monitor each and every one of the many thousands of chemicals that are used in our advanced societies. Chemical contaminants in foodstuffs of animal origin may be classified into three categories: natural contaminants (e.g. mycotoxins), environmental contaminants linked to industrialisation and/or urbanisation (e.g. dioxins and dioxin-like compounds) and authorised chemical products (e.g. residues of veterinary medical products). Chemical hazards may contaminate foodstuffs of animal origin all the way from farm to fork. Contamination may occur in any of the different production systems, and it is difficult to make comparisons between production systems (e.g. extensive versus intensive farming systems) with regard to food safety. Even when we take into account the latest analytical methods, which can detect ever-smaller quantities of residues, the relative importance of chemical contaminants seems to have declined during recent decades due to improvements in information and prevention. Nonetheless, individual incidents can never be ruled out and may have serious economic, health or social repercussions. Particular attention must be paid to chemical hazards, in order to reduce as much as possible the risks to livestock and to the consumer. Continued monitoring and periodic reassessment of risks posed by these contaminants (at the national level) are needed to detect or anticipate new problems, so that appropriate actions can be taken in the interest of public health. More attention should be paid to the production of detailed information, especially with regard to background data (e.g. the objectives of the monitoring, sampling methods, chemicals to be analysed, analytical methods, detection limits, raw data and specified units), in order to obtain a better basis for risk assessment. Such risk assessment provides control authorities with an effective tool for the exchange of information and measures to be taken to ensure food safety.