The moment a mushroom leaves the bed it is still breathing and still warming. ICAR-DMR's post harvest bulletin puts field heat at picking at 15 to 18 C and asks that the mushroom's own temperature be brought to 4 to 5 C as fast as possible.
The manual's practical instruction is to grade, pack and chill at 4 C for 6 to 8 hours before sending to market.

