Pasteurized Straw Mushroom Growing Substrate 5 Pound Grow Bag 100% Pasteurized Straw is very resistant to contamination Our straw is cut, cleaned, Pasteurized and packaged for your convenience Use to cultivate many different species of fungi and will keep for a long time with no refrigeration needed Provides sufficient nutrition, adequate moister content and proper pH Comes in very large mushroom grow bag sealed for freshness