Relationship between temperature and sterilizing efficiency of heat treatments of equal duration. Experimental testing with suspensions of spores in milk heated in an ultra-high-temperature sterilizer

Abstract

Summary A relationship between temperature and sterilizing efficiency of heat treatment at constant time is described and checked experimentally using spores of Bacillus coagulans 604 in a pilot ultra-high-temperature plant. The relation is: where N 0 and N are initial and final concentrations of spores, T the temperature (°C), z the temperature coefficient (°C, z =10/log Q 10 ) and A a dimensionless constant. A special effect of the injection of spores into live steam is observed. The sterilizing efficiency curve can be used in determining the heating temperature for a desired sterilizing efficiency and in predicting the influence of temperature fluctuation on sterilizing efficiency.