A survey of methods of milk production: II. Statistical analysis of bacteriological tests on milk samples

Abstract

1. The results of a survey of the methods of milk production on a random sample of farms in four counties of England and Wales were used in conjunction with bacteriological and keeping quality tests of the milk produced, to estimate the influence on milk quality of factors in equipment and technique.2. Of the many factors in technique investigated, only the sterilization of utensils and the cooling of the milk appeared to affect milk quality. The effects of these two factors differed in some degree with the four tests used.3. Milk samples from machine-milked herds had significantly greater thermoduric colony counts than samples from hand-milked herds. No other factor of equipment showed appreciable association with milk-quality tests.4. Brief recommendations are made about the conduct of any future field survey of factors affecting bacteriological and keeping quality of milk.