ASSESSMENT OF DIOXINS IN FOODS FROM ANIMAL ORIGINS

Dioxin is the common name for 2,3,7,8-tetrachlorodibenzo-para-dioxin ( TCDD) but is also used for the structurally and chemically related pol ychlorinated dibenzo-para-dioxins (PCDD), dibenzofurans (PCDF), and th e coplanar polychlorinated biphenyls (PCB). There are 75 PCDD congener s, 135 PCDF, and 209 PCB. Seven PCDD and 10 PCDF with substitutions at the 2,3,7, and 8 positions are considered toxic, and 11 PCB have diox in-like toxicity. The majority of toxic dioxin is and(or) has been der ived from industrial chlorination processes, incineration of municipal waste) and production of certain herbicides. The potential for health risks due to the cancer-promoting, immunomodulating, and teratogenic activities of dioxins in rodents has raised concerns over their presen ce in the human food chain. The lipophilic nature of dioxins results i n higher concentrations in the fat of animal and fish products, and th eir excretion via milk secretion in dairy cattle may result in relativ ely high concentrations of dioxin contamination in high-fat dairy prod ucts. Surface contamination of plant foods and soil due to deposition of atmospheric emissions may also be a significant direct source of di oxin ingestion for livestock and thereby an indirect source of dioxin for humans. Despite numerous epidemiological studies, dioxin has not b een conclusively determined to be problematic for humans. Certain mana gement practices such as trimming fat from meat, consuming low-fat dai ry products, and simply cooking food can substantially decrease exposu re to dioxin compounds.