Section 19.387 - Ensuring the quality of denaturants(a)General. Proprietors must ensure that the materials they receive for use in denaturing conform to the specifications prescribed in part 21 of this chapter. In addition, the appropriate TTB officer may require that a proprietor test the quality of denaturants at any time.(b)Testing. A proprietor must comply with the following when testing a lot of denaturants: (1) Sampling denaturants. Proprietors must use good commercial practice when taking samples of denaturants for quality assurance testing. Samples of denaturants must be representative of the lot being sampled.(2)Third party testing. A proprietor may employ an outside laboratory or other appropriate third party to test samples of denaturants. In the case of a third party test, the proprietor must obtain a copy of the analysis or statement of findings signed by the chemist who performed the test. On request, the proprietor must provide to the appropriate TTB officer samples of denaturants for quality control testing in a Government laboratory.(c)Substandard denaturants. If TTB or a proprietor finds that a material does not conform to the specifications for a denaturant prescribed in part 21 of this chapter, the proprietor must immediately terminate use of the substandard material as a denaturant. However, the proprietor may continue to use the material as a denaturant after treating or reprocessing the substandard material to correct the deficiency and bring the material into conformity with the applicable specifications.