The Schaeffer–Fulton stain is a technique designed to isolate endospores

Endospore

An endospore is a dormant, tough, and temporarily non-reproductive structure produced by certain bacteria from the Firmicute phylum. The name "endospore" is suggestive of a spore or seed-like form , but it is not a true spore . It is a stripped-down, dormant form to which the bacterium can reduce...

 by staining any present endospores green, and any other bacterial bodies red. The green stain is malachite green

Malachite green

Malachite green is an organic compound that is used as a dyestuff and has emerged as a controversial agent in aquaculture. Malachite green is traditionally used as a dye for materials such as silk, leather, and paper...

, and the counterstain is safranin

Safranin

Safranin is a biological stain used in histology and cytology. Safranin is used as a counterstain in some staining protocols, colouring all cell nuclei red. This is the classic counterstain in a Gram stain...

, which dyes any other bacterial bodies red.

Procedure

Using an aseptic technique, bacteria are placed on a slide and heat fixed. The slide is then suspended over a water bath with some sort of porus paper over it, so that the slide is steamed

Steaming

Steaming is a method of cooking using steam. Steaming is considered a healthy cooking technique and capable of cooking almost all kinds of food.-Method:...

. Malachite green is applied to the slide, which can penetrate the tough walls of the endospores, staining them green. After five minutes, the slide is removed from the steam, and the paper towel is removed. After cooling, the slide is rinsed with water for thirty seconds. The slide is then stained with diluted safranin for two minutes, which stains most other microorganic bodies red or pink. The slide is then rinsed again, and blotted dry with bibulous paper.
After drying, the slide can then be viewed under a light microscope

Optical microscope

The optical microscope, often referred to as the "light microscope", is a type of microscope which uses visible light and a system of lenses to magnify images of small samples. Optical microscopes are the oldest design of microscope and were possibly designed in their present compound form in the...

.

History

The procedure was designed by Alice B. Schaeffer and MacDonald Fulton, two microbiologists at Middlebury College

Middlebury College

Middlebury College is a private liberal arts college located in Middlebury, Vermont, USA. Founded in 1800, it is one of the oldest liberal arts colleges in the United States. Drawing 2,400 undergraduates from all 50 United States and over 70 countries, Middlebury offers 44 majors in the arts,...

, during the 1930s. The procedure also goes by the name Wirtz-Conklin method, referring to two bacteriologists during the 1900s.