Microbiology
General Microbiology Pa 1 (History, Microscopy, Stains and Structure and Physiology of Bacteria)
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A method of sterilization that involves exposure to 100degC for 20 minutes on 3 successive days is known as _____
High-Yield Explanation
1) Inspissation (fractional sterilization) 80 to 85degC for 30 min (for 3 days) by Inspissator For media containing egg or serum - (LJ media, Dorset's egg medium, Loeffler's serum slope) 2. Tyndallisation (Intermittent sterilization):100degC, 20 min, 3 consecutive days. Nutrient media and media containing sugars or gelatin 1st day all vegetative bacteria are killed. On II and III day spores that germinate are killed. 3. Autoclave -121 oC for 15 min with 15 lbs. pressure This type of sterilization is done by steam heat under pressure. Use: Glass ware, surgical dressing, culture media, rubber, gloves, surgical instrument are sterilized by this method (Autoclaved) Sterilization control: Spores of Geobacillusstearothermophilus (Bacillus stearothermophilus), Thermocouples, Browne's tube, Autoclave tapes. 4) Pasturization-used for disinfection of milk holder method: moist heat oC for 30 minutes Flash method :moist heat oC for 15 -20 seconds followed by rapid cooling to the temperature of < 13oC UHT method: moist heat 149 oC for 0.5 sec