This set of Food Microbiology Multiple Choice Questions & Answers (MCQs) focuses on “Food Preservation – Compartmentalization and Heat Processing”.
1. Lactic acid bacteria form ______ in ripened-cream butter.
a) Lactate
b) Sorbate
c) Propylgallate
d) Diacetyl
View Answer
Explanation: These bacteria ferment citrate to produce diacetyl. The lactic acid bacteria give butter a sour taste whereas diacetyl gives it a buttery aroma and taste. This gives the butter a stronger flavor.
2. Churns made of wood are better than churns made of stainless steel.
a) True
b) False
View Answer
Explanation: The cleaning and sanitization of wooden churns is much more difficult than that of stainless steel churns. Hence, the former is being replaced by the latter.
3. Phase inversion is achieved by __________
a) Churning
b) Addition of salt
c) Heating
d) Freezing
View Answer
Explanation: Churning causes phase inversion. The milk which is a fat in water emulsion gets converted to butter which is a water in fat emulsion.
4. Who can be credited with discovering the role of heat in food preservation?
a) Francois Nicolas Appert
b) Charles Mitchell
c) Peter Durand
d) Louis Pasteur
View Answer
Explanation: Francois Nicolas Appert introduced methods to preserve food using the heat from boiling water. Peter Durand is credited with the development of the steel canning method. Charles Mitchell incorporated the metal lining inside the cans to improve the quality and efficiency of food preservation. Pasteur introduced heating of wine to destroy souring bacteria.
5. How many organisms will be present if the original number of organisms is 100000, the death rate constant is 0.002/hr and the time given is 2 hours?
a) 99600
b) 9960
c) 996
d) 99
View Answer
Explanation: Here, N0 is 100000, k is 0.002/hr and t is 2 hours.
N=N0e-kt
Using this formula, N=99600
6. The ____ value represents the temperature needed for the thermal destruction curve to traverse one log cycle. (Temperature is in Fahrenheit)
a) z
b) a
c) t
d) k
View Answer
Explanation: The z value gives us the temperature needed for the thermal destruction curve to cross one log cycle. Numerically, the reciprocal of the slope of the TDT curve gives us the value of z.
7. Which of the following enzymes is deactivated after Pasteurization?
a) Sulfurous acid
b) Polynucleotide Phosphorylase
c) Kinase
d) Alkaline Phosphatase
View Answer
Explanation: Milk naturally contains alkaline phosphatase. This enzyme is deactivated after successful Pasteurization. Therefore, the absence or presence of alkaline phosphatase in treated milk is often a test to check for Pasteurization.
8. What will be the decimal reduction time if the number of organisms at t=0 is 1000 and at t=10 is 100?
a) 100
b) 5
c) 1
d) 10
View Answer
Explanation: Here, N1=1000, t1=0, N2=100 and t2=10
D=(t2-t1)/(logN1-logN2)
Hence, D=10
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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