Effects of Processing on Pesticide Residues in Milk

Chemicals of various types will enter the food chain and eventually be consumed by man. The amount at present appears to be at a safe low level. Continued monitoring is essential to determine if changes occur. The studies on effects of processing on selected chlorinated insecticide residues in milk indicated that heat treatments used for milk drying and sterilization destroyed some of the residues present. The amount of residue destroyed varied with processing treatment and nature of the insecticide residue. Spray drying destroyed in excess of 80% of the lindane residues in raw milk while sterilization caused essentially no change in lindane residues. Heptachlor was destroyed more easily than heptachlor epoxide. Of the insecticides studied, rnethoxychlor was the most stable to heat treatments used in milk processing. Most chlorinated insecticides are relatively resistant to processing techniques used for milk and dairy products. Once residues get into milk they are stable and difficult to remove; therefore, the best policy is to prevent their entrance into milk by proper and careful management of the dairy cow.