Localy owned and operated Fae Foods culture slants are filled and packed into sleeves in their sterile lab environment. The proprietary nutrient agar mix promotes rapid growth, longevity, and makes viewing a breeze. The addition of wood to the mix allows cultures to be stored for up to 2 years in sub 45F conditions (fridge).
The dark coloration is for contrast to the mycelium, they use organic activated charcoal. The Carbon is partially consumed by the mycelium.