Nah the DE keeps weasels and shit out of the grain when in storage before you buy it, if it was not in there wheavils and other bugs would eat it and fuck it. Once you put the grain in the jars the preasure cooker then kills any spores such as mould and it is sterile so nothing will grow in it. You then add mushroom spores, Liquid culture or whatever you are useing and off it goes and colonises the jar.