Define on which severity of heat treatment for pasteurization depends?
The severity of heat treatment for pasteurization depends on:
1.  Heat resistance of target microorganism.  Typical target organisms include Coxiella burnetti, a pathogenic rickettsia  in milk, yeasts and molds - in high acid foods and fermented products and yeasts - in fermented beverages
2.  Sensitivity of product to heat treatment:  For many foods use of High  Temperature  Short Time (HTST) treatment is recommended, which destroys pathogenic microorganisms, but does not do too much damage to food quality.