Inspect straw or other approved substrate before using it. Record where it came from and whether storage has allowed rain, visible mould, soil or chemical contamination. A low purchase price is not a saving if preparation losses or crop failures increase. Use a crop-specific treatment method taught by a competent institution; treatment time and temperature belong to the method and load, not to a generic internet recipe.
The treated material must cool under protected conditions before spawn is added. Mixing hot material with spawn, draining on a dirty floor or handling treated and untreated straw with the same equipment creates different failure routes. Identify the transition from raw to treated material physically. Label each treatment load so that later contamination can be traced to preparation, spawn or handling rather than blamed on the whole room.