This set of Food Microbiology Multiple Choice Questions & Answers (MCQs) focuses on “Food Quality Analytical Techniques – Alternative Methods and Dye Reduction Test (MBRT)”.
1. ________ is the effective resistance of an electrical circuit.
a) Conductance
b) Capacitance
c) Impedance
d) Resistance
View Answer
Explanation: Impedance is the total effective resistance that comprises of ohmic resistances as well as reactance. It is symbolized by the letter Z.
2. ____ can be added into a selective enrichment broth to pre-screen the presence of Salmonella.
a) TMAO
b) SMAO
c) PMAO
d) DMAO
View Answer
Explanation: Trimethylamine oxide (TMAO) is reduced by the enzyme TMAO reductase to convert it into a strongly charged ion. This changes the conductance of the broth.
3. Detection time method is preferred over viable plate count in case of food spoilage.
a) True
b) False
View Answer
Explanation: In the detection time method, the microbial activity is measured directly. This is more useful. Also, rapid detection methods save time and labor. They are also very sensitive and specific.
4. _____ is the energy currency of the cell.
a) ADP
b) ATP
c) AMP
d) NTP
View Answer
Explanation: Adenosine Triphosphate is known as the energy currency of the cell. It is the final product of metabolic processes like photosynthesis, fermentation and respiration. It is produced in the cellular mitochondria.
5. Luciferase can be procured from ________
a) Dragonflies
b) Orcas
c) Frogs
d) Fireflies
View Answer
Explanation: Luciferase is an enzyme which acts on luciferin to emit light in the presence of ATP. This can be used to check cell viability.
6. What color is resazurin?
a) Red
b) Yellow
c) Blue
d) Green
View Answer
Explanation: The color change from resazurin is from slate blue to either pink or white. Resazurin is used to detect viable cells in cell culture. The irreversible color change is directly proportional to the aerobic activity of the organism or cell.
7. What test uses the formation of formazan to check for cell viability?
a) MTT
b) XTT
c) PTT
d) HTT
View Answer
Explanation: In the colorimetric MTT assay, the tetrazolium goes inside the live cells and precipitates as purple formazan crystals. However, XTT assay is preferred over MTT assay as in XTT, the color change is seen outside the cells, whereas, in the MTT assay, the crystals are formed inside and hence it might be difficult to retrieve the original cells.
8. MBRT test is used to check the ________
a) Quality of honey
b) Quality of raw milk
c) Quality of water
d) Quality of starch
View Answer
Explanation: The methylene blue reduction test is used to test the microbiological quality of milk. The methylene blue changes color from blue to clear. This is due to the metabolic activity of the microbes in the milk. They use up oxygen and form reducing products.
Sanfoundry Global Education & Learning Series – Food Microbiology.
To practice all areas of Food Microbiology, here is complete set of Multiple Choice Questions and Answers.
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