Moist heat sterilization methods and microbial growth assessment

Apuntes

Moist Heat Method Condition Effect on Population Boiling water 100 °C, ≥ 1 minute Disinfect Pasteurization 63 °C, 30 minutes Disinfect Autoclave 121 °C at 15 psi,15 minutes Sterilize Tyndallization 100 °C, 15-30 minutes, incubate; repeat ≥ 3 times Sterilize Boiling water is the simplest moist heat method to reduce the number of microbes in a sample and is a common method among campers and hikers to make water drinkable. The World Health Organization (W.H.O.) recommends holding water at a rolling boil (100 °C) for at least 1, depending on altitude (more time for higher altitudes). Pasteurization aims to reduce the number of microbes in food and drink without compromising its taste and texture. There are many different pasteurization methods and depends on the consumable product and the industry or even manufacturer implementing it but all aim to disinfect. Our lab implements the ‘low temperature long time’, or LTLT, pasteurization method, which is 63 °C for 30 minutes. Autoclaves are complex (and sometimes costly) machines designed to sterilize through increased temperature and pressure. Steam heated to 121 °C is injected into a vacuumed chamber, pressurizing it to 15 psi (normal at...