Fig. 93.—A pasteurizer for grape juice, cider, etc., in bottles.
2. Pasteurizing machines are used and the fluid flows through continuously. In one type the temperature is raised to 60° and by “retarders” is kept at this temperature for twenty to thirty minutes ([Figs. 95 to 98]). In another type the temperature is raised to as high as 85° for a few seconds only, “flash process” ([Fig. 99]), and then the material is rapidly cooled. It is certain that all pathogenic microörganisms, except the very few spore formers in that stage, are killed by proper pasteurization. The process is largely employed in the fermentation and dairy industries.
Fig. 94.—A pasteurizer for beer in bottles.
Fig. 95.—A continuous milk pasteurizer.
Fig. 96.—A pasteurizer for cream to be used in making ice-cream.
