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This section includes 172 Mcqs, each offering curated multiple-choice questions to sharpen your Microbiology knowledge and support exam preparation. Choose a topic below to get started.
| 51. |
Soft pickles are made so by pectolytic enzymes mostly from |
| A. | moulds |
| B. | yeasts |
| C. | bacteria |
| D. | none of these |
| Answer» B. yeasts | |
| 52. |
Aerobic Colony Count (ACC), is also known as |
| A. | Total viable count (TVC) |
| B. | Aerobic plate count (APC) |
| C. | Standard plate count (SPC) |
| D. | All of these |
| Answer» E. | |
| 53. |
Advanced treatment is generally used to treat waste water to |
| A. | remove coarse solids |
| B. | remove settleable solids |
| C. | reduce BOD |
| D. | remove additional objectionable substances |
| Answer» E. | |
| 54. |
Which of the following is not an ale type of beer? |
| A. | Weiss beer |
| B. | Porterr |
| C. | Stout |
| D. | Pilsener |
| Answer» E. | |
| 55. |
High acid foods with a pH above 5.3 are especially subjected to |
| A. | flat sour spoilage |
| B. | putrefaction |
| C. | both (a) and (b) |
| D. | TA spoilage |
| Answer» D. TA spoilage | |
| 56. |
The fermentation of wine can be carried out using the strains of |
| A. | Saccharomyces cerevisiae |
| B. | Saccharomyces carlsbergenesis |
| C. | Bacillus subtilis |
| D. | Pedicoccus cerevisiae |
| Answer» B. Saccharomyces carlsbergenesis | |
| 57. |
The magnitude of BOD of wastewater is related to |
| A. | bacterial count |
| B. | amount of organic material |
| C. | amount of inorganic material |
| D. | all of the above |
| Answer» C. amount of inorganic material | |
| 58. |
Biogas production is |
| A. | a temperature-dependent process |
| B. | a temperature independent process |
| C. | an oxygen dependent process |
| D. | none of the above |
| Answer» B. a temperature independent process | |
| 59. |
Canned meat and fish exhibit spoilage by |
| A. | Bacillus species |
| B. | Clostridium species |
| C. | both (a) and (b) |
| D. | Saccharomyces |
| Answer» D. Saccharomyces | |
| 60. |
Activated sludge usually employs an aeration period of ________________ |
| A. | 1 hour |
| B. | 24 hours |
| C. | 10-15 hours |
| D. | 4-8 hours |
| Answer» E. | |
| 61. |
In which of the following organism does iron secreted to form stalks or ribbons attached to the cell? |
| A. | Sphaerotilus |
| B. | Gallionella |
| C. | Thiobacillus |
| D. | Streptococcus |
| Answer» C. Thiobacillus | |
| 62. |
The canned acid foods such as pineapple, tomatoes and pears have been found spoiled by C. pasteurianum. Such spoilage is more likely when the pH of the food is |
| A. | >4.5 |
| B. | <4.5 |
| C. | >5.3 |
| D. | <5.3 |
| Answer» B. <4.5 | |
| 63. |
The immediate source of the flat sour bacteria is usually the |
| A. | plant equipment |
| B. | sugar |
| C. | starch |
| D. | soil |
| Answer» B. sugar | |
| 64. |
Heavy, thick, slimy film of bacteria in the slow process of vinegar manufacture reduces |
| A. | the rate of hydrogenation |
| B. | the rate of acetification |
| C. | the rate of esterification |
| D. | the rate of purification |
| Answer» C. the rate of esterification | |
| 65. |
Which of the following is true to prevent botulism from smoked fish? |
| A. | The fish should be heated at its coolest part to at least 82°C for 30 min during or after smoking |
| B. | Fish should be immediately frozen after packaging and kept frozen |
| C. | Good sanitation should be maintained throughout production and handling |
| D. | All of the above |
| Answer» E. | |
| 66. |
Group I C. botulinum strains generally includes in |
| A. | all types of strains (proteolytic)A, B and F |
| B. | all types of strains (non-proteolytic) E and F |
| C. | all types of strains (proteolytic)C, D and F |
| D. | none of the above |
| Answer» B. all types of strains (non-proteolytic) E and F | |
| 67. |
The most important kind of chemical spoilage of canned foods is the hydrogen swell which is favored by |
| A. | increasing acidities of foods |
| B. | increasing temperature of storage |
| C. | imperfection in the tinning and lacquering |
| D. | all of these |
| Answer» E. | |
| 68. |
Which among the following is a gas producer organism? |
| A. | Streptococcus lactis |
| B. | Lactobacillus fermentum |
| C. | Micrococcus luteus |
| D. | Clostridium butyricum |
| Answer» E. | |
| 69. |
If the mash in the brewhouse is held too long it may undergo |
| A. | butyric acid fermentation |
| B. | lactic acid fermentation |
| C. | both (a) and (b) |
| D. | citric acid fermentation |
| Answer» D. citric acid fermentation | |
| 70. |
Slimy or ropy kraut is caused by |
| A. | encapsulated varieties of Lactobacillus plantarum |
| B. | Lactobacillus lactis |
| C. | encapsulated varieties of Lactobacillus brevis |
| D. | none of the above |
| Answer» B. Lactobacillus lactis | |
| 71. |
Trickling filter is used in which of the following wastewater treatment processes? |
| A. | Primary treatment |
| B. | Secondary treatment |
| C. | Advanced treatment |
| D. | Final treatment |
| Answer» C. Advanced treatment | |
| 72. |
The application of Gamma rays destroys botulism toxin. The dose of gamma rays required for this purpose is |
| A. | 73 Gy |
| B. | 73 Rad |
| C. | 7.3 Mrad |
| D. | 173 Rad |
| Answer» D. 173 Rad | |
| 73. |
Which chemical is used to inhibit mold growth in bread? |
| A. | benzoic acid |
| B. | nitrates |
| C. | sorbic acid |
| D. | lactic acid |
| Answer» D. lactic acid | |
| 74. |
Which of the following organism is found at the initial stages in the batter of Idli? |
| A. | Leuconostoc mesentroides |
| B. | Aspergillus niger |
| C. | Bacillus natio |
| D. | None of these |
| Answer» B. Aspergillus niger | |
| 75. |
Thiobacillus can produce an acidity in the range of pH __________ |
| A. | 7 |
| B. | 5 |
| C. | 3 |
| D. | 1 |
| Answer» E. | |
| 76. |
Oxidation ponds are shallow ponds, generally designed at the depth of |
| A. | 2 to 40 feet |
| B. | 4 to 6 feet |
| C. | 1 to 3 feet |
| D. | 5 to 8 feet |
| Answer» B. 4 to 6 feet | |
| 77. |
The micro-organisms causing wine spoilage are |
| A. | wild yeast |
| B. | moulds |
| C. | bacteria |
| D. | all of these |
| Answer» E. | |
| 78. |
Which of the following is not true for the thermal resistance of the bacterial cells? |
| A. | Cocci are usually more resistant than rods |
| B. | Higher the optimal and maximal temperatures for growth, higher the resistance |
| C. | Bacteria that clump considerably or form capsules are difficult to kill |
| D. | Cells low in lipid content are harder to kill than other cells |
| Answer» E. | |
| 79. |
Which of the following is a food infection? |
| A. | Salmonellois |
| B. | Botulism |
| C. | Staphylococcal intoxication |
| D. | None of these |
| Answer» B. Botulism | |
| 80. |
The ability of B. coagulans to grow in tomato juice depends upon the |
| A. | number of spores present |
| B. | the availability of oxygen |
| C. | the pH of the juice |
| D. | all of these |
| Answer» E. | |
| 81. |
The growth of black-pigmented Bacillus nigrificans, a causative agent of black pickle is favoured by |
| A. | presence of carbohydrate like glucose |
| B. | low level of available nitrogen |
| C. | neutral or slightly alkaline brine |
| D. | all of the above |
| Answer» E. | |
| 82. |
Which is not a form of biomass energy? |
| A. | Incineration of solid waste |
| B. | Composting to produce methane |
| C. | Ethanol and methanol production for auto fuel |
| D. | Photovoltaic production of hydrogen |
| Answer» E. | |
| 83. |
The Bacillus cereus causes gasteroenteritis by the production of an exoenterotoxin which is released in food as a result of |
| A. | cell growth |
| B. | cell autolysis |
| C. | cell permeation |
| D. | cell damage |
| Answer» C. cell permeation | |
| 84. |
The time temperature combination for HTST paterurization of 71.1°C for 15 sec is selected on the basis of |
| A. | Coxiella Burnetii |
| B. | E. coli |
| C. | B. subtilis |
| D. | C. botulinum |
| Answer» B. E. coli | |
| 85. |
The most important organism involved in manufacture of Koji is |
| A. | Aspergillus oryzae |
| B. | Aspergillus soyae |
| C. | both (a) and (b) |
| D. | Lactobacillus lactis |
| Answer» D. Lactobacillus lactis | |
| 86. |
Which of the following products have higher acidity and lacks aroma? |
| A. | Cultured buttermilk |
| B. | Cultured sour cream |
| C. | Bulgarian milk |
| D. | Acidophilus milk |
| Answer» D. Acidophilus milk | |
| 87. |
Which of the following acts as a carbon source for Enterobacter aerogenes? |
| A. | Peptone |
| B. | Sodium citrate |
| C. | Yeast extract |
| D. | Tryptone |
| Answer» C. Yeast extract | |
| 88. |
Jellies and jams are rarely affected by bacterial action. |
| A. | True |
| B. | False |
| C. | May be |
| D. | Can't say |
| Answer» B. False | |
| 89. |
Spoilage of bread is caused by which of the following microorganism(s)? |
| A. | Saccharomyces |
| B. | Rhizopus |
| C. | Leuconostoc |
| D. | Pseudomonas |
| Answer» C. Leuconostoc | |
| 90. |
Pickled cucumber is made from fermented salt-stock pickles. |
| A. | True |
| B. | False |
| C. | May be |
| D. | Can't say |
| Answer» C. May be | |
| 91. |
Gassy spoilage of green olives is usually caused by |
| A. | Enterobacter spp |
| B. | Bacillus spp |
| C. | Clostridium spp |
| D. | all of these |
| Answer» E. | |
| 92. |
Suspected colonies of Staphylococcus aureus when grown on Baird-Parker medium shall show |
| A. | coagulase activity |
| B. | protease activity |
| C. | catalase activity |
| D. | none of these |
| Answer» B. protease activity | |
| 93. |
Which of the following is generally not referred to the sewerage system? |
| A. | Sanitary sewers |
| B. | Storm sewers |
| C. | Combined sewers |
| D. | Solid sewers |
| Answer» E. | |
| 94. |
Black kraut is caused by |
| A. | the plant enzymes |
| B. | the micro-organisms |
| C. | the combined actions of plant enzymes and micro-organisms |
| D. | none of the above |
| Answer» D. none of the above | |
| 95. |
The butyric acid type of fermentation in acid or medium acid foods, with swelling of the container by the carbon dioxide and hydrogen gas is caused by |
| A. | C. butyricum |
| B. | C. pasteurianum |
| C. | both (a) and (b) |
| D. | C. sporogenes |
| Answer» D. C. sporogenes | |
| 96. |
NaCl can act as |
| A. | antagonist at optimal concentrations |
| B. | synergistically if added in excess of optimum level |
| C. | Both (a) and (b) |
| D. | None of the above |
| Answer» D. None of the above | |
| 97. |
Plate count of bacteria in foods generally use the plating medium consisting of |
| A. | peptone, yeast extract, glucose, sodium chloride, agar and distilled water |
| B. | yeast extract, glucose, sodium chloride, agar and distilled water |
| C. | peptone, glucose, sodium chloride, agar and distilled water |
| D. | peptone, yeast extract, glucose, sodium chloride and distilled water |
| Answer» B. yeast extract, glucose, sodium chloride, agar and distilled water | |
| 98. |
The more oxidizable organic material, the lesser the BOD. |
| A. | True |
| B. | False |
| C. | May be |
| D. | Can't say |
| Answer» C. May be | |
| 99. |
Staphylococcal intoxication is caused by the toxin m the food from |
| A. | Staphylococcus aureus |
| B. | S. cerevisiae |
| C. | S. thermophillus |
| D. | none of these |
| Answer» B. S. cerevisiae | |
| 100. |
Which of the following(s) is/are porteolytic or putrefactive decomposing proteins with the production of malodorous compounds such as H2S, mercaptans, ammonia, indole and skatole? |
| A. | C. sporogenes |
| B. | C. putrifaciens |
| C. | both (a) and (b) |
| D. | C. butyricum |
| Answer» D. C. butyricum | |