OBSERVATIONS ON THE THERMAL INACTIVATION OF THE ORGANISM OF Q FEVER IN MILK.1

Abstract

Q Fever is an infectious disease of man. Cattle, sheep and goats, who for the most part suffer inapparent infections with the organism, are the important sources of infection for man. These animals shed the organism in their milk. This manuscript reports on the cooperative studies designed to determine the times and temperatures needed to eliminate the causative rickettsiae, Coxiella burnetii, from cows milk. It is reported that the present minimum standard of pasteurization by the vat method of 143° F. for 30 minutes is inadequate, but the temperature of 145° F. for 30 minutes will eliminate the organism. The pasteurization of milk according to the present standards for HTST equipment of 161° F. for 15 seconds seems adequate to destroy C. burnetii.