Pasteurization is based on a short-term increase in temperature, which causes the destruction of pathogenic microorganisms­. Unlike overcooking, it does not significantly change the quality of the food. There is no sterilization during pasteurisation. The effect of heat must be adapted to the individual beverage. The higher the temperature, the shorter the time required to kill microorganisms. The higher the number of bacteria, the longer the time required.

The goal of pasteurization of beer, cider is to treat and increase its biological durability. Cans and glass bottles are treated by so-called tunnel pasteurization or flow pasteurization.In the passage of the bottles through the tunnel shepherd, the bottles are sprayed with water at different temperatures to heat them to the desired pasteurization temperature, usually 61–62 ° C and then gradually cooled to an outlet temperature of about 25–30 ° C. The total time it takes for bottles is 40–60 minutes (shorter for cans). Pasteu­rizing temperatures of 70–74 ° C are used in the flow pasteurizer and even a short elongation leads quickly to pasteurization with negative consequences on beer taste and smell. Often, pasteurization is replaced by membrane filtration.

source: https://cs.wikipedia.org/wiki/Pasterace