[Computation for the sterilisation process in rendering plants (author's transl)].

Abstract

In the present paper a mathematical model for the computation and costing of the sterilisation process in rendering plants has been developed and the computation of the F value in the canning industry has been used as a guide. In this, a test germ with the heat resistance parameters z = 10 degrees C and Dr = 10 sec is taken as a guide. If the steam-pressure heating regulation of the German Carcass Disposal Act which prescribes a temperature of 133 degrees C during 20 min after decomposition of the soft parts, is related to such a test germ, then a comparable sterilisation time of roughly 300 min at 121 degrees C is obtained, the heating-up phase and the cooling-down phase being disregarded. In computing the total lethality of a practical heating procedure in a dry melter, the result is a comparable heating process of abt. 640 min at 121 degrees C. While making allowance for the time lags in the temperature development in meat and bones during autoclaving and on the basis of a heating-up value of 100 minutes at 121 degrees C, various steam-pressure heat treating systems are suggested within the temperature range from 120 to 135 degrees C, having a comparable total lethal effect varying in duration.