Procedure : Steps 1 to 3 and step 5 are demonstration steps and will be performed by your counsellor. Observe these steps carefully.

1. The cotton plugs/caps of the test tubes, flasks and bottles containing microbial cultures are 1oosened.so that during autoclaving adequate heat can penetrate into the bottle/test tube/flask to kill the microbes.

2. The cultures in glass flasks, bottles, tubes and petridishes at 15 psi are autoclaved for 15 minutes at 120°C so that the microbes are killed. If a pressure cooker is used for this purpose, it is to be heated for 30 minutes after the pressure is formed.

3. After pressure in the autoclave is completely down, i.e. at zero, the lid of the autoclave is opened. The glassware containers are allowed to cool down for some time and then taken out carefully one by one from the autoclave so that culture material is not spilled out.

4. After the counsellor has taken out the glassware from the autoclave, with the help of a spatula empty the autoclaved culture material from the flasks/bottles/test tubes/petriplates in a disposable bag and seal the bag.

5. This autoclaved culture material can be disposed off by two methods: i) burying, ii) incineration. You will learn the process of burying while performing Activity 3 of this exercise. Incineration means heating the material at a very high temperature so that biological material is turned into ash. The incineration is done to destroy the dead culture materials and medium completely so that nutrients are not available for regrowth of microbes. Keep the material to be incinerated in a heat-resistant container.

Put this container in the incinerator and switch it on. Do not open the incinerator when the switch is on or until the temperature has come down to zero after the incineration process is over. Your counsellor will demonstrate the process of incineration for you.

6. You can dispose the autoclaved material by any of these methods that is available at your study centre. If you undertake the incineration process, collect the ash in a paper bag, seal it and put this bag in the collecting bin.

For burying, put the autoclaved culture material in a disposable bag and seal it and follow the steps given.