I have no proof, but anecdotal evidence suggests that since cannabis users aren't getting sick from them that we can tolerate them.
We have bacteria's on everything we eat, drink, touch, digest and breath.. They are part of our normal life. Plants in nature can't get nutrients without various microbes digesting organic material to feed them.
Whether we realize it or not, we are learning a lot about science as we consider the various ways to grow our plants, and part of that is recognizing the roll microbes play in our life.
My 2c