... Specific Rotation, Top Quality√ First domestic L-Theanine manufacturer through USP auditAbout Us:Zhejiang Tianrui Chemical CO., Ltd., situated in south ... . Our company are ISO22000 and ISO14001 certified. Our products obtained USP, HACCP, KOSHER, HALAL and other international certificates. We are ... circulating water, with innovative product ecological safety control system. ISO certificate L-Theanine