In an endospore stain, what color are spores and vegetative cells after staining?

• A. Spores appear green; vegetative cells appear pink/red
• B. Spores pink; vegetative cells green
• C. Spores red; vegetative cells blue
• D. Spores appear green; vegetative cells appear pink/red

Answer: (D)

This question tests how endospore staining differentiates spores from vegetative cells. In the Schaeffer-Fulton endospore stain, heat drives the malachite green dye into the resistant spores. The heat helps the dye penetrate the tough spore coat, and once washed, the spores retain the green color. The surrounding vegetative cells don’t hold onto malachite green and instead take up the counterstain, safranin, which colors them pink/red. So the final appearance is green spores with pink/red vegetative cells.