Sterilisation in pressure cookers

  1. Wrap a stack of 3-4 dishes with tinfoil, and put a piece of autoclave tape on top of the parcel.
  2. Put the petri dish parcels in pressure cooker baskets.
  3. Add 2L of water to your pressure cooker, and add the petri dish parcels. Ideally they will sit above the water in the cooker.
  4. Put the lid on the pressure cooker and turn up to full.
  5. When the pressure cooker comes up to pressure, turn the heat down a little and put a timer on for 20min.
  6. Make sure the pressure stays up. When 20 min is up, take the pressure cooker off the heat.
  7. When the pressure cooker has cooled, take the petri dishes out with oven gloves.
  8. Check the autoclave tape has changed colour, label the dishes with the date and the type of media.

Petri dishes can be stored in the fridge for a month or so.