Dave Smith wrote:
>
> Arri London wrote:
>
> >
> > > Actually, it is a biochemical process that deals with the pesticides in the
> > > previous level of the food chain. A lot of the basic components of the
> > > "growing medium" is hay, grass, grains, feed and whatever else the horse
> > > ate. Most of the rest of it is the straw bedding from the stalls. The first
> > > step of the "growing medium" retrieval is called "mucking out" in stable
> > > talk..... cleaning stalls. It is trucked away to the mushroom farms where it
> > > is composted and, as some have indicated, sterilized in autoclaves.
> >
> > But there still can be residues and unmetabolised pesticides which the
> > sterilisation would inactivate.
>
> What pesticides? The original food was grass, hay, grains and feed. They don't use
> pesticides on hay and fodder crops.

Perhaps not in your part of the US. But I've seen crop dusters spraying
hay fields locally. It certainly wasn't water or fertiliser; I've lived
on farms before LOL!

They don't use pesticides on grain except soon
> after germination.

Which is probably about the worst time to spray if one is trying to
avoid accumulation.

Animal feed is usually pretty clear of pesticides. Straw is
> the chaff from grain crops, so the amount of residual pesticides is pretty close to
> zero. AFAIAC, pesticide residue in mushroom growing medium is pretty much a non
> issue.

Perhaps perhaps not. Since crops are rotated, residues can be picked up
from fields which have been sprayed. It is probably a non issue but not
necessarily because spraying doesn't happen ...