Pesticide Residues in Fluid Market Milk

Abstract

DURING the fall of 1955, each of the 16 Food and Drug Districts submitted at least 100 samples of market milk to the Division of Antibiotics, Food aind Drug Administration, Washington, D. C., where they were checked for residual antibiotics (1).In addition, 800 of these samples, 50 from each district, were analyzed by the Division of Food for pesticide residues.Surveys in 1948residues.Surveys in , 1949residues.Surveys in , and 1951 had had shown that traces of DDT could be found in about 25 percent of market milk samples.A fairly specific but somewhat long procedure, the Schechter-Haller method (2-4), was then avail- able for detecting DDT, but more recently many other pesticides have come into use, and residues of lindane, technical BHC, methoxy- chlor, Rhothane, heptachlor, toxaphene, chlor- dane, members of the aldrin group, Perthane, Dilan, Lethane, and others might be encoun- tered in milk.For most of these no specific test method exists.In addition to the group of chlorinated organics, trace residues of the organic phosphate pesticides, such as parathion, and Systox, might be found.A further com- plication was recognized from the start: Little is known about the metabolism of most of these products; some or all might degrade to un- known products of unknown toxicity.Because of the dearth of specific methods, and because the application singly of the available ones to lhundreds of samples would involve more work than a limited staff could handle, a bio- assay "sort-out" test was applied.E. P. Laug of the Division of Pharmacology has perfected a bioassay with flies and applied it to the de- termination of DDT, lindane, endrin, and other pesticides (5-7).When only one toxicant is known to be present, the results can be made Vol.72, No. 8,