Question

Which of the following stain is used to prepare the smear of lactobacillus?

• A. Methylene blue
• B. Safranine
• C. Crystal voilet stain
• D. None of the above

Answer 1

The correct option is A Methylene blue

• Steps involved in the preparation of the smear of lactobacillus and observing under the microscope
• Take a very small drop of yogurt with the toothpick and smear it for 2 to 3 seconds on the slide.
• Place a small drop of methylene blue solution on a microscope slide. Wear gloves.
• Place a cover slip on top. Remove excess solution around the cover slip with a paper towel or tissue.
• View in the compound microscope at 4 x or 10 x initially, before moving to higher magnification. Lactobacillus bacteria will appear small even at the highest magnification.
• Hence Methylene blue stain is used to prepare the smear of lactobacillus.
• So, the correct answer is 'Methylene blue'.