A COMPARISON OF DIFFERENT METHODS OF CHEMICAL DISINFECTION OF FARM DAIRY UTENSILS

Abstract

A comparison of separate and combined detergent disinfectant treatments of milk contact surfaces using an alkaline detergent and sodium hypochlorite was made by farm trials of naturally contaminated milking machine equipment and by laboratory soiled milking machine units. With six farms tested over a period of 3 months the combined treatment was superior and was still further improved by the addition of a sanitizing rinse immediately before milking. With laboratory soiled equipment there was no significant difference between the two methods, though the addition of a further sanitizing rinse to the combined method brought about a significant improvement. With the combined process the disinfectant rinse of 75 ppm hypochlorite exerted a greater disinfecting action than the hot detergent‐disinfectant wash of 200 ppm hypochlorite. This appeared to be solely a result of the high pH of the alkaline wash. The importance of the sanitizing rinse immediately before milking was demonstrated, and its value attributed not to the concentration of disinfectant but to the timing of the rinse. Disinfectant rinses done several hours before milking (or bacteriological rinsing) allowed development of microorganisms on the utensil surface. Copyright © 1968, Wiley Blackwell. All rights reserved