Green, black, or orange spots are signs of contamination. Healthy mycelium is white and fluffy.
Not sure? Do the cotton swab test: gently press a clean cotton swab against the suspicious spot. If colour transfers to the swab, it's likely contamination. If not, it's probably just bruising (which is harmless).
More info on identifying contamination: https://www.zamnesia.com/content/546-how-to-identify-a-contaminated-mushroom-culture
If your kit is contaminated, send us a photo along with your order number and batch number.