I was seeding plates with OP50-1 w/strep and I got this nasty contamination. The plates seemed fine before and the contamination was originally restricted to the bacterial lawn, but has started growing to other parts of the plates. I grew the bacteria in LB media and used brand new M9 media when resuspending the bacteria pellet. I believe the contamination was in the seeding material, but I’m not sure why and I’ve never had contamination this bad.
I won’t be using that M9 anymore, but wanted to ask for any help/tips. Could it have come from the LB plate where I picked the colony from? I ask because I streaked an LB plate with the same seeding material that ended up contaminating all those plates. This was before I saw any contamination on them. On that note, after seeding I leave the plates out for 24 hours and then store them, would it be bad for me to leaving them out for longer to catch contamination like this sooner since it took longer for the contamination to grow/become visible when it was stored in the fridge.
Also new user, so it’s not letting me upload pictures!
Thank you for any help!