This set of Food Microbiology Multiple Choice Questions & Answers (MCQs) focuses on “Nutrient Elements: Macronutrient and Micronutrient”.
1. Which of the following is an intrinsic factor for the growth of microbes in food?
a) Nutrients
b) Temperature
c) Gaseous Environment
d) Relative Humidity
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Explanation: Intrinsic factors such as nutrients, water content, pH etc. are determined by the food environment whereas extrinsic factors are determined by the environment in which the food is stored. The synthesis of cellular components and energy gives rise to the growth and development of microbes in food. The nutrients required for this are obtained from the cell’s immediate environment.
2. Which of the following is not considered to be a nutrient in food?
a) Minerals
b) Water
c) Protein
d) Lipids
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Explanation: Every food contains 5 main nutrient groups, namely: Proteins, carbohydrates, lipids, vitamins and minerals. Water is considered to be a medium instead of a nutrient. The quantity of every nutrient group varies with the type of food and its function.
3. Molds are least capable of hydrolyzing complex molecules outside the cell.
a) True
b) False
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Explanation: Molds are actually most capable of producing certain extracellular enzymes to break down complex molecules outside and then transporting them inside the cell. Complex molecules include starch, cellulose, casein etc. Also, molds are most capable of hydrolyzing polysaccharides.
4. Which of the following is not a disaccharide?
a) Maltose
b) Sucrose
c) Lactose
d) Xylose
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Explanation: Xylose is a monosaccharide which is also called wood sugar. It is found in the embryos of many edible plants. Maltose is a disaccharide comprising of 2 glucose molecules whereas sucrose has 1 glucose molecule and 1 fructose molecule. Lactose contains 1 galactose molecules and 1 glucose molecule.
5. Creatinine is an example of __________
a) Simple Proteins
b) Conjugated Proteins
c) Non-Protein Nitrogenous Compounds
d) Peptides
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Explanation: Creatinine is an example of Non-Protein Nitrogenous Compounds (NPNs). NPNs are compounds which have the ability to be converted to proteins with the help of microbes in a ruminant gut. On hydrolysis, simple proteins break down to give amino acids and/or simple carbohydrate groups. Conjugated proteins are simple proteins along with a non-protein group, whereas, peptides are short polymers of amino acid monomers.
6. Which of the following is not an example conjugated proteins?
a) Mucin
b) Globulin
c) Casein
d) Myoglobin
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Explanation: Globulin is a simple protein found in milk. Mucin is a glycoprotein whereas casein is a phosphoprotein and myoglobin is a metalloprotein.
7. Extracellular lipases hydrolyze glycerides to _________ and _________
a) Fatty acids and glycerol
b) Waxes and sterols
c) Aldehydes and ketones
d) Carbohydrates and oils
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Explanation: Microbes produce extracellular lipases to break down glycerides into fatty acids and glycerol. Fatty acids can be used as an energy substrate once inside the cell and glycerol can be metabolized separately. Certain extracellular lipid oxidases convert unsaturated fatty acids to aldehydes and ketones.
8. Vitamins and minerals are micronutrients required for microbial growth and development.
a) True
b) False
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Explanation: Microbes need small amounts of elements like phosphorus, calcium, manganese etc. Many microbes can synthesize Vitamin B on their own. Also, most foods have sufficient amounts of nutrient for the proper growth of microbes.
9. Escherichia coli can produce indole from _______
a) Tyrosine
b) Glutamic Acid
c) Valine
d) Tryptophan
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Explanation: The Indole test is a biochemical test which determines the ability of an organism to convert tryptophan to indole. Therefore, indole producing E. coli can be differentiated from non-indole producing Enterobacter species. This conversion is possible due to a system of intracellular enzymes, tryptophanase.
10. Which of the following acids is not produced during the metabolism of carbohydrates?
a) Hydrochloric acid
b) Propionic acid
c) Butyric acid
d) Acetic acid
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Explanation: Hydrochloric is an inorganic acid whereas acetic acid, propionic acid and butyric acids are organic acids. The production of these organic acids has a negative effect on the growth, development and survival of many bacteria.
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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