Moeller stain

Moeller staining involves the use of a steamed dye reagent in order to increase the stainability of endospores.

Endospores are surrounded by a highly resistant spore coat, which is highly resistant to excessive heat, freezing, desiccation, as well as chemical agents.

The slide is then heated over a bunsen burner, or suspended over a hot water bath, covered with a paper towel, and steamed for 3 minutes.

The slide is rinsed with acidified ethanol, and counter-stained with Methylene blue.

An improved method involves the addition of the surfactant Tergitol 7 to the carbol fuchsin stain, and the omission of the steaming step.