Polysorbate 80 is used as an emulsifier in foods, though research suggests it may “profoundly impact intestinal microbiota in a manner that promotes gut inflammation and associated disease states.

Polysorbate 80 is a surfactant and solubilizer used in a variety of oral and topical pharmaceutical products. Polysorbate 80 is also an excipient that is used to stabilize aqueous formulations of medications for parenteral administration, and used as an emulsifier in the making of the antiarrhythmic amiodarone.

Some mycobacteria contain a type of lipase (enzyme that breaks up lipid molecules); when these species are added to a mixture of polysorbate 80 and phenol red, they cause the solution to change color, so this is used as a test to identify the phenotype of a strain or isolate. 

On RODAC agar plates used in microbiological control, polysorbate 80 counteracts disinfectants often found on sampled surfaces, thereby allowing the microbes found on these surfaces to grow.