They are hard to rid of, and once you get hit - it's a paranoia that follows you for some time. I look at surfaces all the time now *laughs*! 3 weeks ago I bought a "Fluker's Cricket feed" bottle from a local Petco. I used it a few times before I realized It was INFESTED! (Petco refunded me for that, PLUS replaced my crickets). Now I'm checking containers in stores. Those pesky little mites!!! I've had to throw out a couple of feeder colonies in the past year - what a bother!
They grow quickly in high humidity. You're only option is probably going to be a good cleaning.
Someone told me that you can get something through your local feed store to help rid of them. I can't for the life of me remember what it was called. I've never used it. I always cleaned my surfaces with bleach water.
Good luck to you!