Pharma Interview Q and A Sep-29-21

September 29, 2021: Pharmaceutical Interview Questions and Answers

#Endospore staining #SchaefferFultonStaining

1. Which indicators are used for spore staining?

Malachite green (a triarylmethane dye) and a safranin (an azonium compound) counterstain is useful tool in identifying the presence or absence of spores.

This is referred to as the Schaeffer-Fulton stain.

2. Explain the Schaeffer-Fulton staining method for endospore staining technique?

1. Prepare a bacterial smear on a clean slide, air dry and gently heat fix.

2. Cover the slide with a piece of paper towel, and place on a staining rack over the water bath with boiling water.

3. Flood the paper towel on the slide with Malachite green (primary stain). Steam the slide for about 5 minutes.

4. Remove the slide from the water bath, and remove the paper towel from the slide.

5. Allow the slide to cool, and then rinse with deionized water until the water runs clear.

6. Drain excess water and apply Safranin (counterstain) for 2 minutes.

7. Rinse Safranin off with deionized water, and blot the slide dry with blotting paper.

8. Examine the slide with a light microscope under oil immersion objective


Endospores appears green

Vegetative cells appear red or pink

image 9

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