Australia's Science Forum

After just getting a new microwave, and I have done my first batch of agar plates, in the microwave. Which I would say turned out very well. I shall never go back to doing them the old way, on the hot plate etc. I would now like to know how long you need to microwave the agar plates to dispose of them.

Thank you

Plates, once finished with, must be made safe before throwing away. The usual method is to place inside an autoclave bag and then sterilised by microwaving on medium/high for 15 minutes. Plastic plates will melt (hence the bag). After about 20 minutes the microwave and plates will have cooled down and the bag can safely be thrown away. If no microwave or autoclave is available an ordinary domestic pressure cooker can be used, or an incinerator may be used.

Other equipment may be decontaminated by being placed in a suitable disinfectant such as Dettol for 24 hours.

When all manipulations are done, the bench is disinfected once again. The last step should be to wash the hands thoroughly with antibacterial soap and hot water before leaving the lab.

Is there a way to clean out incubators? We had some plates go in which weren't very well sealed (two pieces of sticky tape to make a cross on top of the petri dish) and now our incubator is a rather smelly... which I'm thinking can't be good! I just want to know if there's something I can spray in it without destroying the inside. Vanilla fridge wipe?

THanks Richard, would an oven bag do the same job? Or would I use two bags??

A couple of tablespoons of Bi carb soda in a petri dish bottom for the whiff in the incubator (good to keep moisture down also!) + any surface anti bacterial spray to wipe the inside clean will suffice. We use Viraclean hospital disinfectant from Q Stores. Go easy on it though or nothing will grow in it if the plates are not 100% sealed! If it's really smelly we put the bi carb in while the plates are incubating.

1 x oven bag should be fine if it's big enough (convection/airflow around the dishes is prefered for maximum effect) so long as they don't split open or melt.