The copper content of some Queensland butters

Abstract

The copper content of over 250 samples of commercial butter representing churnings from 30 factories ranged from 0.05 to 0.70 p.p.m. Comparison of butters from a factory with untinned copper equipment with those from a factory with stainless steel equipment showed a marked incidence of high copper content in the former and little evidence of copper in the latter. An examination of copper contamination on the farm showed that the first milk through the milking machine was heavily charged with copper in one plant when bare brass equipment was used, while no such contamination was evident in a plant with stainless steel and glass equipment. Some suggestions for reducing copper contamination in milk, cream and butter are offered.