Nonpathogenic, slow growing scotochromogens and nonphotochromogens commonly produce lipase which hydrolyzes polysorbate 80 into oleic acid and polyoxyethylated sorbitol, whereas pathogenic Mycobacterium spp. do not produce this enzyme4. Polysorbate 80 Hydrolysis Substrate Concentrate contains the indicator, neutral red dye. Neutral red dye is normally red at pH 7.0, but after binding with polysorbate 80 it changes to amber or straw color that it has at an alkaline pH. Certain Mycobacterium spp. hydrolyse polysorbate 80 which is then no longer available to bind the indicator causing the neutral red dye to revert to its original red color5,6.This reagent contains neutral red as an indicator, disodium and monopotassium phosphate buffers and Polysorbate 80.Not all products are available for sale in all territories. Please inquire.Remel™ and Oxoid™ products are now part of the Thermo Scientific brand.