This document gives an overview of the general methods and practices I employ in the laboratory.
Glassware vs. Plastics:
For several reasons I prefer glassware over plastics when working with cultures:
1. to reduce waste and carbondioxide emissions 2. to sterilize the medium inside the petri-dish, and minimize the possibilities for contamination 3. to save money
Autoclaving cycles
Media is autoclaved at 121°C (assumption as the autoclave has no thermometer) for at least 20 minutes. (higher temperatures will caramelize the sugars rendering the medium unfit for fungi.) The autoclave is brought up to temperature. When the pressure relief valve opens the temperature is lowered to keep the contents of the vessel from boiling. ( in this case 2 will do) The vessel is then removed from the stove and put into the laminar flow, till the pressure is reduced to normal. The dishes are removed from the vessel while still hot and lined under the laminar flow and the UV light till solid. Optionally the lids can be opened and the medium can be slightly dried to reduce condensation. ( a method Dr. V. Glöckner suggested)
The petri dishes are always sealed with parafilm to avoid airborne contaminants, and even more important to avoid accidental opening and contaminating by other lab-users.
The petri-dishes are stored upside-down to prevent airborne contaminants from settling on the medium.