The largest number on a mushroom ingredient specification is often the least difficult item to compare. The harder work is deciding whether the document controls a recognisable material, whether its tests have interpretable meanings and whether a batch can be released against it without filling gaps by assumption. A useful specification is an agreement about identity, composition, relevant risk limits and physical or application attributes. The certificate of analysis (COA) then reports a particular batch against that agreement. Reversing those roles by building a specification from whichever results happen to appear on one COA weakens future batch control.