In moderate amounts it is not generally considered an adulterant.
In this bulletin they do not classify saltpeter as an adulterant.
It was then in demand, it is said, as an adulterant of quinine.
It is often added to, as an adulterant, or substituted for the true Almond oil.
The roots of this, after being ground and roasted, are used either as a substitute or an adulterant ...