Residue levels of hexachlorobenzene in meat and poultry in the food supply of the USA.

Since the early 1970s, the Food Safety and Inspection Service of the US Department of Agriculture has monitored fat samples from meat and poultry for residues of hexachlorobenzene (HCB). The violative level for enforcement activities is 0.5 ppm. Data on HCB residues found in meat and poultry have been organized on the basis of nationwide occurrence over time, according to geographic groupings and according to species. A further distinction has been made between grazing animals, e.g., cattle, sheep, horses, and non-grazers such as swine and poultry. From 1972 to 1977, HCB residues were detected in all species tested. Of the samples analysed, the percentage containing HCB ranged from 7 (in 1973) to 41 (in 1977). In 1978, the percentage declined to 26 and continued to drop in 1979 to 8. From 1980 to the present time, detectable levels (greater than 0.01 ppm) of HCB have been found in 3-6% of the samples analysed with 95% of those samples containing less than 0.1 ppm. Only seven out of more than 25,000 samples analysed since 1980 contained HCB levels greater than 0.05 ppm. Comparisons of HCB in animal tissues collected from the five geographic regions of the Food Safety and Inspection Service indicated frequently that in the western and south-western regions of the USA a greater number of animals showed detectable levels of HCB in their fat. In 1984, the incidence for all samples was 4.4%. Figures for the regions varied from 1.4% in the southeast to 6.6% in the southwest. Comparison of the frequency of HCB in the fat of different species indicated that horses, sheep and cattle show detectable amounts of HCB more frequently than poultry and swine. These data seem to reflect production practices in that animals which graze at some period of their lives may be exposed to HCB more frequently than non-grazing animals.