Page 84 - MNUmicrobiology practical 2025

General Microbiology & Immunology (PM 401) second level Semester 4 2024/2025

Schaeffer-Fulton Stain

Principle
• In the Schaeffer-Fulton procedure, endospores are first stained by heating the

bacterial smear with malachite green, a weak basic dye.

• Heat makes the stain permeate through the tough spore coat components,

Dipicolinic acid-Ca2+. Once the spore has taken up the stain it never loses the stain

by decolorizing with distilled water.

• Whereas vegetative cells lose the primary stain color and appear to be colorless.

Safranin is used as the counterstain the vegetative structure.

General Microbiology & Immunology (PM 401) Practical note Page 73