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To kill all spores in a clear liquid can take up to 22 hours with glutaraldehyde and even longer with formaldehyde. The presence of solid particles may lengthen the required period or render the treatment ineffective. Sterilization of blocks of tissue can take much longer, due to the time required for the fixative to penetrate.
Disinfection uses liquid chemicals on surfaces and at room temperature to kill disease-causing microorganisms. Ultraviolet light has also been used to disinfect the rooms of patients infected with Clostridioides difficile after discharge. [14] Disinfection is less effective than sterilization because it does not kill bacterial endospores. [15]
Ultraviolet germicidal irradiation (UVGI) is a disinfection technique employing ultraviolet (UV) light, particularly UV-C (180–280 nm), to kill or inactivate microorganisms. UVGI primarily inactivates microbes by damaging their genetic material, thereby inhibiting their capacity to carry out vital functions.
To prove sterility, biological indicators are used. Biological indicators contain spores of a heat-resistant bacterium, Geobacillus stearothermophilus. If the autoclave does not reach the right temperature, the spores will germinate when incubated and their metabolism will change the color of a pH-sensitive chemical.
Moist heat sterilization processes sterilize using hot air that is heavily laden with water vapor, which plays the most important role in the sterilization. [1] [2] Boiling a sample for 30 minutes or more will kill virtually all vegetative cells present, but will not kill spores, which can germinate shortly thereafter and resume growth ...
Tyndallization is a process from the nineteenth century for sterilizing substances, usually food, named after its inventor John Tyndall, that can be used to kill heat-resistant endospores. Although now considered dated, it is still occasionally used. [citation needed]
A disinfectant is a chemical substance or compound used to inactivate or destroy microorganisms on inert surfaces. [1] Disinfection does not necessarily kill all microorganisms, especially resistant bacterial spores; it is less effective than sterilization, which is an extreme physical or chemical process that kills all types of life. [1]
Ultra-high temperature processing (UHT), ultra-heat treatment, or ultra-pasteurization [1] is a food processing technology that sterilizes liquid food by heating it above 140 °C (284 °F) – the temperature required to kill bacterial endospores – for two to five seconds. [2]