Spiral Foods Shiitake Mushrooms are of the highest quality and grown outdoors on oak logs without chemicals and added flavours. The shiitake mushrooms contain a rich amount of minerals and B Vitamins. Donko is a type of shiitake that grows slowly in the cold season and is gathered when its top is 60 per cent -80 per cent opened. Due to the long growth period, it leaves the Donko Shiitake with a soft texture, rich flavour and aroma.