Brilliant Green Agar 30 MCQs Mock Test

Welcome to the Brilliant Green Agar Mock Test, designed for students, laboratory technologists, and microbiology professionals who want to evaluate their understanding of this important selective culture medium.

Brilliant Green Agar is widely used for the selective isolation of Salmonella species from stool, food, and environmental samples. Its selective agents inhibit competing intestinal flora, allowing easier identification of pathogenic Salmonella colonies based on their characteristic appearance.

This mock test contains 30 carefully designed questions that reflect real laboratory and examination patterns. It is an effective tool for assessing theoretical knowledge and practical understanding of selective media used in enteric microbiology.

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Brilliant Green Agar MCQs Mock Test

Please read before starting the Brilliant Green Agar – 30 MCQs Mock Test. This test includes 30 multiple-choice questions, each with one correct answer. There is no negative marking, so attempt all questions. Avoid refreshing or closing the page to prevent losing your progress. After answering all questions, you may review your responses before submitting. If you want a Certificate, enter your correct Full Name and active Email after completing the test and before submission. Your certificate can be downloaded directly from the result page once the test is submitted.

Read Full Article: Brilliant Green Agar 50 FAQs and 30 MCQs

1 / 30

Category: Clinical Laboratory

Which medium is recommended for Salmonella Typhi isolation?

XLD Agar

Hektoen Enteric Agar

Bismuth Sulphite Agar

MacConkey Agar

2 / 30

Category: Clinical Laboratory

What is the primary use of Brilliant Green Agar?

Selectively isolate Salmonella (excluding S. Typhi)

Grow Pseudomonas species

Detect lactose-fermenting bacteria

Isolate Staphylococcus aureus

3 / 30

Category: Clinical Laboratory

Incubation temperature for food enrichment in Selenite Broth:

35°C

43°C

55°C

25°C

4 / 30

Category: Clinical Laboratory

Brilliant Green Agar inhibits growth of:

Gram-positive bacteria

Salmonella species

Yeasts

Non-lactose fermenters

5 / 30

Category: Clinical Laboratory

What is the concentration of brilliant green dye in BGA?

0.08 g/L

0.0125 g/L

10.0 g/L

5.0 g/L

6 / 30

Category: Clinical Laboratory

For water testing, BGA requires:

Freezing samples first

Filtration and enrichment

Direct plating without enrichment

Anaerobic incubation

7 / 30

Category: Clinical Laboratory

What is the shelf life of dehydrated BGA powder?

1 year

4 years

6 months

2 years

8 / 30

Category: Clinical Laboratory

Prepared BGA plates should be stored:

At 10–25°C away from light

Submerged in water

In a CO₂-rich environment

Frozen at -20°C

9 / 30

Category: Clinical Laboratory

Shigella flexneri ATCC 12022 on BGA should show:

Yellow colonies

Red zones

Good growth

Inhibited growth

10 / 30

Category: Clinical Laboratory

Which ingredient acts as the pH indicator in BGA?

Brilliant green

Phenol red

Lactose

Sodium chloride

11 / 30

Category: Clinical Laboratory

Which test is ESSENTIAL after isolating colonies on BGA?

Gram staining

Biochemical/serological confirmation

Antibiotic susceptibility

Motility testing

12 / 30

Category: Clinical Laboratory

BGA is classified as:

Radioactive

A hazardous medium

Non-dangerous under standard use

Carcinogenic

13 / 30

Category: Clinical Laboratory

Escherichia coli on BGA shows:

Yellow-green colonies with yellow halos

Inhibited growth

Both Yellow-green colonies with yellow halos and Inhibited growth

Red colonies with red zones

14 / 30

Category: Clinical Laboratory

Salmonella colonies on BGA typically appear as:

Metallic green sheen

White to pink colonies with red zones

Yellow colonies with green halos

Blue translucent colonies

15 / 30

Category: Clinical Laboratory

How much BGA powder is needed to prepare 1 liter of medium?

58.09 g

20.0 g

5.0 g

10.0 g

16 / 30

Category: Clinical Laboratory

Which medium should be used alongside BGA for better recovery?

Sabouraud agar

Blood agar

Less selective media (e.g., MacConkey)

Chocolate agar

17 / 30

Category: Clinical Laboratory

Why might Salmonella Typhi show poor growth on BGA?

Needs anaerobic conditions

It is inhibited by brilliant green

Requires higher pH

It ferments lactose

18 / 30

Category: Clinical Laboratory

What is the sterilization method for BGA?

Boiling for 10 minutes

Autoclaving at 121°C for 15 minutes

UV irradiation

Filtration

19 / 30

Category: Clinical Laboratory

Which pH change occurs with lactose fermentation?

No change

Alkaline (red)

Neutral (pink)

Acidic (yellow)

20 / 30

Category: Clinical Laboratory

Which organism may mimic Salmonella on BGA?

Staphylococcus aureus

Bacillus subtilis

Enterococcus faecalis

Proteus vulgaris

21 / 30

Category: Clinical Laboratory

BGA is used in pharmaceutical testing with:

Novobiocin

Vancomycin

Tetracycline

Ampicillin

22 / 30

Category: Clinical Laboratory

Overheating BGA during preparation may:

Promote lactose fermentation

Degrade selective agents

Enhance brilliant green activity

Increase agar solidification

23 / 30

Category: Clinical Laboratory

Which carbohydrates are included in BGA?

Lactose and sucrose

Mannitol and lactose

Xylose and lactose

Glucose and sucrose

24 / 30

Category: Clinical Laboratory

Why is BGA unsuitable for Shigella isolation?

Requires anaerobic incubation

Contains inhibitors for Shigella

Promotes Shigella overgrowth

Lacks nutrients for Shigella

25 / 30

Category: Clinical Laboratory

Food samples are pre-enriched in:

Saline solution

Buffered Peptone Water

Mannitol Salt Broth

LB broth

26 / 30

Category: Clinical Laboratory

Which enrichment broth is used for food samples before BGA plating?

Tryptic Soy Broth

Selenite Cystine Broth

Thioglycollate broth

Nutrient broth

27 / 30

Category: Clinical Laboratory

Pseudomonas species on BGA form:

Blue colonies

No growth

Pink to red colonies

Yellow zones

28 / 30

Category: Clinical Laboratory

Which organism is NOT typically isolated using BGA?

Salmonella Typhi

Salmonella Enteritidis

Salmonella Typhimurium

Salmonella Abony

29 / 30

Category: Clinical Laboratory

Sodium chloride in BGA primarily:

Acts as a carbon source

Inhibits Gram-positive bacteria

Maintains osmotic balance

Enhances lactose fermentation

30 / 30

Category: Clinical Laboratory

Which QC strain confirms BGA selectivity?

Staphylococcus aureus ATCC 25923

Escherichia coli ATCC 25922

Salmonella Typhimurium ATCC 14028

All of the above

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Final Thoughts

The Brilliant Green Agar Mock Test is a valuable resource for strengthening your understanding of selective culture media and enteric pathogen identification. Regular practice improves diagnostic accuracy, enhances exam performance, and builds confidence in microbiology laboratory procedures.

Continue practicing with additional microbiology mock tests to further improve your knowledge of clinical and food microbiology.

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