Astaxanthin and cantaxanthin are carotenoids that are used as color enhancers in aquatic animals. The residue limits for cantaxanthin, are set for livestock and fishery foods, and the test methods are described in "Testing methods for pesticide residues in foods, feed additives, or substances that are components of veterinary drugs" (Notification No. 0124001 of the Safety Division, PFSB dated January 24, 2005).
In this report, a High Performance Liquid Chromatography (HPLC) was used with a photodiode array detector (PDA), which is versatile for many diverse applications.