Effect of Low-Temperature Cleaning of Milking Equipment on the Microbiological Quality of Raw Milk

Abstract

Effect on the microbiological quality of milk of using a special cleaning detergent (Diversey-Wyandotte, Inc.) for low-temperature (initial 43.8°C, end of wash 35.4°C) washing in a milking parlor pipeline system was compared to regular high-temperature (initial 73°C, end of wash 43.8°C) wash of the system. Microbiological quality of the milk was determined by standard plate count (SPC) and psychrotrophic bacterial count (PBC). Cleanliness of equipment was evaluated by measurement of calcium deposits and visual inspection. Statistical analysis of data over time (June 5 to September 16, 1980) indicated no difference in SPC and PBC of milk between low-and high-temperature washing and, although there was a significant negative slope of PBC with time, this was due to factors other than treatment. Calcium soil deposition and visible evaluation of the equipment were not different for the wash temperatures.

Control of Microorganisms

“…Besides the health of the dairy cow, standards have been developed for the housing and milking areas so that they can be maintained in a satisfactory manner. There are requirements for the equipment used to obtain, handle, and store the milk, and for the equipment to be properly cleaned, sanitized, and maintained (Guterbock, Blackmer, and Duffy 1984;Stone, Myhr, and Davie 1983). Grade A milk must be cooled to lOoe or less within two hours after milking to maintain the quality.…”