Mites in fruit fly culture

This is my second attempt to culture fruit flies, and in both cultures i have had mite problems. I am not sure where they are coming from as my superworms and cricket don't have any.

Any ideas and help is needed

Where are you getting your material from (both culture and flies)?
are you SURE that those are clean?
how about any other things you're putting into the culture?

Somewhere there's contamination.
If you're concerned, I would get an established clean culture going
from a 3rd party and then retry to make your from that.
it's possible that any mites may be brought in from wild populations
that are attracted the smell of your culture. landing on the lid
with the mites hopping off and creeping through your filter inside onto their new hosts.