Methods of sterilization:(1) Physical method:a) Dry heat sterilization: It includes flaming technique, hot air oven method and sterilization by I.R radiations.b) Moist heat sterilization - It includes autoclaving, tyndalization and pasteurization.c) Radiation sterilization - By UV and gamma radiations.(2) Chemical methods: Chemical methods of sterilization includes sterilization by heating with bactericides and gaseous sterilization.(3) Mechanical methods: In this process sterilization is done by filtration with bacteria proof filters. These are ceramic filters, seitz filter, sintered glass filters, sintered metal filters, and membrane filters