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Viability Staining Method For Bacteria

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To distinguish between living and dead cells.


The viability Staining Method mainly used to detect living and dead cells in culture. This method is based on the fact that, certain changes take place in dead cells which result in these cells giving a different reaction to stains from that of living cells.



  • 2-3 weak old bacterial cultures.
  • Loeffler’s methylene blue solution.
  • Dilute carbol fuchsim solution
  • Bunsen burner
  • Clean glass slide.
  • Blotting paper
  • Microscope.

Procedure of Viability Staining

  1. Take a clean slide and make it grease-free by washing it with soap and water.
  2. Allow to air dry.
  3. Take an inoculating loop and sterilize it by holding it on bunsen burner flame until it becomes hot red. Allow cooling the loop.
  4. Transfer the bacterial culture on the slide by using this sterile cooled loop.
  5. Spread the culture on the slide.
  6. Heat fix the smear, by passing the slide through the flame of bunsen burner for 2-3 times. It will fix the cell at the surface of slide.
  7. Flood the smear with methylene blue for 10 minutes.
  8. Rinse the smear with running tap water until the smear appears pale blue.
  9. Add carbol fuchsin on slide.
  10. Wash immediately with tap water.
  11. Blot dry the slide.
  12. Now, slide is ready to observe under microscope.

Viability Staining Method For Bacteria Flow Chart

Viability Staining Method For Bacteria Flow Chart
Viability Staining Method For Bacteria Flow Chart

Result of Viability Staining

  • Live Bacterial Cell: Appear purple.
  • Dead Bacterial Cell: Appear red or pink.
  • Living Spore: Stained Pink
  • Dead Spore: Stain Blue


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