Bacteriological Examination of Pipeline Milking Machines by Rinsing the Entire System

The results of bacteriological examination of rinses of the entire systems of 12 pipeline milking machines were compared with a similar examination of the milk collected while they were used for milking. The machines were cleaned in three different ways and showed varying degrees of complexity. There was a close correlation between the results when the milk was collected with the maximum of cleanliness during milking. This is attributed to the localization of most of the micro‐organisms present in the milking machine in the junctions and complex parts of the machine and not on the surface of the equipment, so they are removed with the same efficiency by cold water or warm milk. The number of micro‐organisms retrieved by water during successive rinses (or by the milk during milking) decreased at a rate which depended either on the level of initial contamination of the equipment, its design or on the types of micro‐organisms present. Recommendations are made for the interpretation of the results of rinsing.