Physical Methods of Sterilisation — Tyndallisation

know in detail about different types of sterilisation such as physical type of sterilisation

Tyndallisation — 100ºC

John Tyndall first devised the process. It was designed to remove spores and to retain other nutrient values likes sugars, proteins, serum. Intermittent sterilisation of Fractional sterilisation is also called Intermittent sterilisation because it proceeds in three steps for three consecutive days.

Step 1:

Heating at 100ºC — Kills all vegetative cells present but does not kill the spores.

Step 2:

Incubation at 37ºC — It facilities the remaining spores to germinate at the optimum temperature of the incubator.

Step 3:

Heating again at 100ºC — All vegetative cells germinated from the spores in the second step will be killed.

An addition of 24 hours incubation is also allowed for any remaining spores that have failed to germinate in the first step. A device called an Arnold steriliser is designed to carry out the process of sterilisation. It helps in generating the free flow of steam.