[Contamination of milk and milk products with chlorinated hydrocarbons in the Westphalian area. II. Results and discussion]

During the time of August 1972 til end of January 1974 samples of butter from 20 dairies from the westfalian area were investigated with regard to their content of chlorinated hydrocarbons. In all samples of milk and butter could be proved: HCB, alpha-, beta-, and gamma-BHC, Heptachlorepoxid (HE), DDT, DDE, DDD, Dieldrin and PCB's, not however, Aldrin, Heptachlor and o,p'-DDT. With HCB, alpha- and gamma-BHC a dependance on the season was observed with maximum values during the winter months. With DDT, DDE and HE the variations were less. With PCB's dependencies on the season or influences of the location were not be recognised. The structure of farming seems to have a significant influence on the contents of HCB. In the course of butter processing the content on chlorinated hydrocarbons related to milk fat is not changed, metabolization does not play a role, either. With the start of lactation the concentration of chlorinated hydrocarbons especially of PCB's are increased as could be shown with single samples.

[On the contamination of milk and milk products with chlorinated hydrocarbons. I. Methods]

A method of gaschromatographic determination of chlorinated insecticides in milk and butter in the presence of PCB's is described. The fatty components were extracted from milk after adding sodium oxalate and ethanol with diethyl ether and petrol ether. The clean up of the extracts was carried out according to a modification of the method of Hadorn and Zürcher with propylene carbonate as a selective solvent.

[Phospholipase D of cereals (author's transl)]

Phospholipase D containing water insoluble fraction was isolated from mature barley; the enzym preparation only had weak phospholipase B activity. The phospholipase D of barley was activated by Ca2+, diethyl ether and sodium dodecyl sulphate (SDS); EDTA inhibited the enzyme to an extent of 10% of the original activity. Diethyl ether and SDS showed and additive effect. Phospholipase D activated by CaC12, diethyl ether and SDS exhibited a sharp optimum at pH 6.6. Lysophosphatidylcholine was hydrolysed much slower than phosphatidylcholine. Diethyl ether and SDS also increased the breakdown of the lysophosphatidylcholine.