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MIB611S - MICROBIOLOGY - 2ND OPP - JULY 2022 |
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nAmIBIA unIVERsITY
OFSCIEnCEAno TECHnOLOGY
FACULTY OF HEALTH, APPLIED SCIENCES AND NATURAL RESOURCES
DEPARTMENT OF HEALTH SCIENCES
QUALIFICATION: BACHELOROF HUMAN NUTRITION
QUALIFICATION CODE: 08BOHN
LEVEL: 6
COURSE CODE: MIB611S
COURSE NAME: MICROBIOLOGY
SESSION: JULY 2022
PAPER: THEORY
DURATION: 3 HOURS
MARKS: 100
EXAMINER:
SUPPLEMENTARY /SECOND OPPORTUNITY QUESTION PAPER
MS FIINA NAMUKWAMBI
MODERATOR: DR LARAI AKU-AKAI
INSTRUCTIONS
1. Answer ALL the questions.
2. Write clearly and neatly.
3. Number the answers clearly.
PERMISSIBLE MATERIALS
NONE
THIS QUESTION PAPER CONSISTS OF 5 PAGES {Including this front page)
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SECTION A
QUESTION 1
(10 MARKS)
Evaluate the following statements in each numbered section and select the most appropriate
answer from the given possibilities. Write the appropriate letter next to the number of the
statement/phase in the ANSWERBOOK.(Each question carries 1 mark.)
1.1 Which of the following is the characteristics of micro-organisms:
A. Too small to be seen with the naked human eye
B. Cells are relatively simple and less specialized than those plants and animals
C. Can be handled and cultured in the laboratory
D. All of above
1.2 Saccharomyces cerevisiae is:
A. Bacteria
B. Mold
C. Yeast
D. Virus
1.3 The characteristics of yeast include:
A. Unicellular and usually egg-shaped
B. Reproduce by spores
C. Larger than molds, smaller than bacteria
D. Reproduce by spores
1.4 Pasteurization heat treatment is designed to kill primarily:
A. Vegetative cells
B. All forms of microorganisms
C. Spore cells
D. Vegetative and spore cells
1.5 Shiga toxin-producing strains are caused by:
A. Clostridium perfringens
B. Escherichia coli
C. Campylobacter jejuni
D. Staphylococcus aureus
1.6 It is not recommended to eat raw eggs because:
A. Raw eggs could be contaminated with Clostridium perfringens causing severe
abdominal pain
B. Raw eggs cannot easily be digested and may cause abdominal clamps
C. Raw eggs could be contaminated with salmonella resulting into severe
infections
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D. Natural antimicrobial such as lysozyme occurring in egg white prevent all
microbial growth
1.7 Which of the following is the first method used for controlling microbial growth of in food
processing plant:
A. Control by antimicrobial preservatives
B. Control by heat
C. Control by low temperature
D. Control of microorganisms by physical removal
1.8 Which of the following is not a gram-negative bacteria:
A. Staphylococcus aureus
B. Listeria monocytogenes
C. Compylobacter jejuni
D. Escherichia coli
1.9 Which of the following is the main carbohydrate in milk:
A. Lactose
B. Lactic acid
C. Fructose
D. Maltose
1.10 The following are some of the extrinsic factors which affects microbial growth in food:
A. pH and temperature of storage
B. Presence and concentration of gases in the environment
C. The biological structure of the food
D. Relative humidity and moisture content
QUESTION 2
(10 MARKS)
Assess the following statements and decide whether they are true or false. Write only the
number of the question and next to it indicate your answer as true or false in the ANSWER
BOOK.{Each question carries 1 mark)
2.1 Micro aerophiles can grow in environments with adequate oxygen.
2.2 Penicillium digitatum is the type of microorganisms responsible for spoilage in oranges.
2.3 During the second stage of bacterial curve growth, the viable count remains in
equilibrium, the dying cells, and the newly formed cells are equal.
2.4 The lag phase is the first stage in the bacterial growth curve.
2.5 Osmophilic yeast tolerates and grows in high osmotic pressure.
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2.6 Eugenol is an antimicrobial constituent found in clove.
2.7 Aerobic microorganisms require positive Reduction Potential (Eh) value (oxidized) for
growth.
2.8 Sulfur dioxide is used to control microorganisms in soft fruits and fruit juices.
2.9 True yeast converts sugar into alcohol and carbon dioxide e.g production of wine
and beer.
2.10 Lactic acid bacteria lack amylase enzyme to breakdown polysaccharides.
SECTION B
QUESTION 3
(28 MARKS)
3.1 Differentiate between following terms and concepts:
3.1.1 Good bacteria and bad bacteria
(4)
3.1.2 Food poisoning bacteria and food spoilage
(4)
3.1.3 Selective media and non-selective media
(4)
3.1.4 Controlled fermentation and back slopping fermentation
(4)
3.1.5 Facultative anaerobes and anaerobes bacteria
(4)
3.2 Outline any four (4) main characteristics of yeast and moulds each?
(8)
3.3 Why is it important to understand the sources of microorganisms in food?
(4)
QUESTION 4
(19 MARKS)
4.1
Mrs Didi prepared a home-made beverage drink called Oshikundu. She uses sorghum flour and
previous Oshikundu as a starter culture and it was contaminated with presence of flies,
cockroaches, and rats. All the family members including her husband and four children
consumed this beverage drink. After 72 hours, everyone in the house became sick and
developed a range of symptoms that included: stomach cramps, vomiting, bloody diarrhea,
headache, body aches, fever, and chills.
4.1.1
4.1.2
4.1.3
4.1.4
What is the mode of causation of this illness?
(1)
What condition is this family suffering from? Justify your answer?
(2)
What is the name of the causative agent responsible for such illness?
(2)
Highlight four (4) main characteristics of the organism responsible for this illness?
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(4)
4.1.5 Propose five (5) measures to control the transmission of this disease?
(5)
4.2 Propose five (5) measures to control the transmission of Vibrio cholerae?
(5)
SECTION C
QUESTION 5
(20 MARKS}
5.1 Microorganisms grow and cause food spoilage, which for some foods could be relatively
high based on the water activity. With relative examples, outline three (3) different
categories in which food can be classified.
(6)
5.2 Write a short summary on the following terms as they are related to controlling
microorganisms by access:
5.2.1 CIP
(5)
5.2.2 COP
(5)
5.3 Outline four (4) groups of sanitizers use in food processing plants for effective removal
of pathogens and reduce microbial load after cleaning?
(4)
QUESTION 6
(13 MARKS)
6.1 Describe the four (4) steps in processing semi-dry sausages in controlled fermentation? (4)
6.2 Briefly explain the major three (3) factors that need to be considered for effective control
of micro-organisms in food under heat treatment?
(9)
GOOD LUCK!!!
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