MCQ Bank
What is the role of the dilution factor in the serial dilution process?
- A) Ensure sample aesthetics
- B) Increase the accuracy of microbial concentration determination
- C) Accelerate microbial counting
- D) Enhance microbial isolation
What is the primary purpose of screening and selecting LAB colonies based on diacetyl and lactic acid production?
- A) Ensure product quality
- B) Assess bacterial growth
- C) Increase pasturization
- D) Reduce flavor
A population of cells or multicellular organisms growing in the absence of other species or types are known as:
- A) All of these
- B) mixed culture
- C) Pure culture
- D) solid culture
How are the test tubes labeled after the completion of the serial dilution?
- A) Labels based on microbial growth
- B) Labels based on colors
- C) Random labels
- D) Labels based on dilution factor
What is the role of Aspergillus niger in food spoilage?
- A) Improving nutritional content
- B) Causing undesirable changes
- C) Enhancing flavor
- D) Producing preservatives
What is the primary objective of performing serial dilution in microbiology?
- A) Accelerate microbial growth
- B) Convert dense solution to usable concentration
- C) Enhance sample traceability
- D) Increase microbial density
What is the recommended action if moisture is present on agar plates in the streak plate method?
- A) Add more agar
- B) Incubate overnight
- C) Sterilize the plates
- D) Discard plates
Which organism milk is a rich source of Lactobacillus microorganisms
- A) Goat
- B) sheep
- C) cow
- D) deer
What is the purpose of pasteurizing raw cow milk samples in the isolation of lactic acid bacteria?
- A) To kill harmful bacteria
- B) To enhance flavor
- C) To reduce temperature
- D) To eliminate LAB
Why is the purpose of serial dilution to isolate colonies of microorganisms on a solid medium?
- A) Enhance microbial growth
- B) Ensure sample aesthetics
- C) Accelerate microbial counting
- D) Achieve a countable number of colonies
Which of the following is the YPS medium abbreviation?
- A) Yeast, Peptone, Sulphite
- B) Yttrium, Peptone, Sulphite
- C) Yeast, Peptone, Sulphur
- D) Yeast, potasium, Sulpheric acid
What is the significance of incubating yoghurt samples at 42°C for 4-6 hours?
- A) Enhance flavor
- B) Convert lactic acid to lactose
- C) Kill harmful bacteria
- D) Accelerate fermentation
While isolating Aspergillus from pearl millet, which of the following is NOT used in the isolation process?
- A) Sterile potato dextrose agar
- B) Fermenting vessel
- C) Sterile polythene bags
- D) Raw cow milk
The common name of saccharomyces cerevisiae is
- A) rancid yeast
- B) Fresh baker yeast
- C) baker yeast
- D) ripened yeast
Which media is used for the growth of Lactobacillus from goat milk
- A) MRS
- B) GYC
- C) Hektoen enteric agar
- D) MS
For the isolation of Lactobacillus at lab scale how much milk sample is required?
- A) 70ml
- B) 80ml
- C) 60ml
- D) 50ml
Which of the following product is used from S. cerevisiae.
- A) Chees
- B) wine
- C) yogurt
- D) bread
Which of the following media is used for the growth of acid-producing microorganisms?
- A) Basal media
- B) MEA
- C) MacConkey agar
- D) GYC
Why is it crucial to label test tubes with corresponding dilution factors in the serial dilution process?
- A) Improve sample aesthetics
- B) Ensure traceability and accuracy
- C) Speed up incubation
- D) Enhance microbial growth
Why is the Gram staining mentioned in the context of lactic acid bacteria (LAB)?
- A) To measure enzyme activity
- B) To determine sugar content
- C) To classify bacteria
- D) To assess acidity