That's an excellent question to ask your allergist/health-care provider.

Honestly, I have no real knowledge about mushroom allergies. But, most allergies are triggered by a protein in the allergenic substance - the protein is the allergen. If it were me I would avoid contact with the soil as I would suspect it of possibly containing the protein/allergen. The likelihood is probably low, but there is some level of risk. The food issue is not uptake (I don't know of plants taking in soil bound proteins), but if the offending allergen is soil resident then there is a risk of food contamination from soil contact. The greatest risk would most probably be with root vegetables, then low-growing leafy stuff (lettuce, spinach, etc.), then the higher growing fruiting stuff (peppers, tomatoes). If the produce was well washed I would guess that it wouldn't be a problem, but it's a guess. edit - meant to add. you sure are lucky to have a source of SMS. I used to live about 15 miles from a major mushroom center, and the spent stuff is incredibly good compost. This post was edited by TXEB on Tue, Apr 23, 13 at 19:10

In a discussion of mushroom compost a while back in an azalea group, someone pointed out that this compost is alkaline and not good for acid-loving plants. So please be careful about what you put in your raised beds, if you're going to plant shrubs -- Leafgro is neutral, but manure can be too high in nitrogen unless well aged and mixed with other stuff (better for veggies). Might want to consider starting your own composting area now that you have the room and material for it....

I will say a word about compost. For several years I bought compost at the Ft. Smith landfill. It started out being pretty good stuff, I think at one time they had inmates or people from the Bost center picking out the plastic trash bags. Now the bags are shredded along with the wastes and screened, or blown out. The compost has a lot of shredded plastic in it which gets worse as the compost decays. The plastic blows all over your yard and garden and you spend years trying to get rid of it. The only reason I am saying this is to suggest that you know about the compost before you buy it because it can have chemicals, plastic or about anything else in it. I have used 3 scoops of mushroom compost from Miami so far and am happy with if. If you get compost from a city facility, find out how they process it. You may not want it even if it is free. Larry