Are you using vinegar in your cultures? When I forget is when I usually see mold. I use NE Herp media as well. Excelsior is also a potential culprit if you use it.
As far as a spot of mold, take a spoon and scoop it out. You may at least be able to slow the spread if it doesn't outright stop it.
As far as a spot of mold, take a spoon and scoop it out. You may at least be able to slow the spread if it doesn't outright stop it.