Moist heat sterilization Autoclave: a device somewhat like a fancy pI ressure cooker The air initially present is forced out the chamber is filled with saturated stream 121°Cor15 pounds 15-30min 1. All air must be flushed out of the chamber. or it will not reach 121C even though it may reach pressure of 15 pounds 2. The chamber should not be packed too tightly
Moist heat sterilization • Autoclave: a device somewhat like a fancy pressure cooker. • The air initially present is forced out the chamber is filled with saturated stream • 121oC or 15 pounds 15-30min 1. All air must be flushed out of the chamber, or it will not reach 121oC even though it may reach pressure of 15 pounds. 2. The chamber should not be packed too tightly
Pasteurization Milk, beer, and many other beverages are treated with controlled heating at temperatures well below boiling. Not sterilize, just pasteurized Past:63°C,30min HTST:72°C,15sec UHT:140-1500C,1-3sec
Pasteurization • Milk, beer, and many other beverages are treated with controlled heating at temperatures well below boiling. Not sterilize, just pasteurized. • Past : 63oC, 30min • HTST: 72oC, 15sec • UHT: 140-150oC, 1-3sec
Dry heat sterilization 160-170°C2-3h Suitable for glass petri dishes and pipettes Not suitable for heat-sensitive materials like many plastic and rubber items
Dry heat sterilization • 160-170oC 2-3h • Suitable for glass petri dishes and pipettes • Not suitable for heat-sensitive materials like many plastic and rubber items
Filtration Heat-sensitive solution Depth filters: diatomaceous; unglazed porcelain Membrane filters: membranes with pores about 0.2um in diameter are used to remove most vegetative cells. but not viruses Air: 1. Surgical masks and cotton plugs on culture vessels 2. Biological safety cabinets
Filtration • Heat-sensitive solution • Depth filters: diatomaceous; unglazed porcelain. • Membrane filters: membranes with pores about 0.2m in diameter are used to remove most vegetative cells, but not viruses. • Air: 1. Surgical masks and cotton plugs on culture vessels. 2. Biological safety cabinets