429 Bulletin UASVM, Agriculture 65(2)/2008 pISSN 1843-5246; eISSN 1843-5386 FOOD CONTAMINANTS - DIOXINS AND PCBs LIKE COMPOUNDS - Tofana Maria, Sonia Ancuta Socaci Food Safety and Quality Control Lab., University of Agricultural Science and Veterinary Medicine, Faculty of Agriculture, 3-5 Manastur Street, 400372 Cluj-Napoca, Romania, tel. 0264596384, e-mail: tofanam@yahoo.com Key words: dioxin, PCB, food contaminants, chlorinated dioxins, food safety control Abstract: Dioxins are very persistent unwanted by-products of the manufacture of certain industrial chemicals or are produced during various combustion and incineration processes. From the 1930s until the 1970s, PCBs were produced in many industrial countries, including the United Kingdom. The main purpose of this production was for use in electrical equipment. Dioxins and PCBs are environmental contaminants which find their way in very low concentrations into many food sources. They are particularly found in fatty foods, including milk. Although the industrial sources of dioxins and PCBs are now strictly controlled, both groups of chemicals are very persistent and will remain in the environment for many more years. Dioxin is an unintended byproduct of natural events such as volcanoes and forest fires as well as manmade processes such as manufacturing, incineration, paper and pulp bleaching, and exhaust emissions. It is found throughout the industrialized world in air, water, soil as well as in food. Exposure to dioxin can come through working in industries where dioxin is a byproduct, industrial accidents, through food and human breast milk and in drinking water. Overall, exposure to dioxin sources by skin contact or breathing has very small incidence. Despite the presence of dioxins in human milk, breast-feeding should be encouraged and promoted on the basis of convincing evidence of its benefits to the overall health and development of the infant. INTRODUCTION: DIOXINS AND PCBs LIKE COMPOUNDS Dioxin is the name generally given to a class of super-toxic chemicals, the chlorinated dioxins and furans, formed as a by-product of the manufacture, molding, or burning of organic chemicals and plastics that contain chlorine (North Atlantic Treaty Organization, 1988). Dioxin form a class of chlorine-containing chemicals widely recognized as some of the most toxic chemicals ever made by humans. They are produced as the unwanted by-products of industrial processes involving chlorine or chlorine-containing materials such as the manufacture of polyvinyl chloride plastic (PVC); pesticide production; and paper bleaching (Safe S, 1994). The most toxic and widely studied form of dioxin is 2,3,7,8- tetrachlorodibenzo- p-dioxin or TCDD. It is measured in parts per trillion (ppt)( Ablborg U G, Becking G C et al., 1994),.Dioxin is a colorless, odorless organic compound containing carbon, hydrogen, oxygen and chlorine. Dioxins and PCBs are two groups of organic chemical contaminants that have made their way into the food chain. ‘Dioxins’ is a generic term given to polychlorinated dibenzo-p- dioxins and dibenzofurans. Concerns over dioxins arose from one particular compound, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), which was found to be toxic to some species of laboratory animals and also produced clinical effects in workers who were exposed to it through industrial accidents)( Ablborg U G, Becking G C et al., 1994). TCDD and 16 other dioxins which contain chlorine at positions 2, 3, 7 and 8 of the molecule may have some toxic effects, although the other 16 are thought to be less toxic than TCDD. At present, the