Chapter 26 Applied and Environmental Microbiology
26.1 Multiple Choice Questions
1) Food microbiology applies to
A) the use of microorganisms to make food.
B) the control of microbial activity to prevent foodborne illness.
C) using microbes to solve agricultural problems.
D) the use of microorganisms to make food and the control microbial activity to prevent
foodborne illness.
E) using microbes to improve livestock and to solve agricultural problems.
2) A researcher studying the impact of agricultural pesticides on native plants discovers a
bacterium capable of degrading small amounts of a specific pesticide. The researcher then
modifies the bacterial species in the lab to increase the rate of pesticide degradation. This
research represents
A) applied microbiology.
B) environmental microbiology.
C) food microbiology.
D) both food microbiology and environmental microbiology.
E) both applied microbiology and environmental microbiology.
3) Which of the following common food products is prepared by the fermentation of cabbage?
A) kimchi
B) coleslaw
C) sauerkraut
D) kimchi and sauerkraut
E) coleslaw, kimchi and sauerkraut
4) Why are “fortified” foods more likely to spoil than are unfortified foods?
A) The added vitamins and minerals can promote microbial growth.
B) The foods are fortified by the addition of vitamin-producing microbes.
C) Every step of modification or manipulation of food increases the chance for contamination.
D) Vitamins are frequently contaminated by the microbes that produced them.
E) The vitamins require a neutral pH environment, which is suitable for many microbes.
5) Which of the following is a lactic acid bacterium used in the production of food?
A) Aspergillus oryzae
B) Gluconobacter
C) Leuconostoc
D) Penicillium
E) Saccharomyces cerevisiae
6) Which of the following is produced by fermentation?
A) beef jerky
B) pasteurized milk
C) pepperoni
D) mozzarella cheese
E) pepperoni and mozzarella cheese
7) Sulfur dioxide is added to “must” in the production of wine to
A) improve the flavor.
B) allow more control over the fermentation process.
C) provide a necessary nutrient for the fermentation process.
D) prevent tannins from leaching out of wood into the fermenting wine.
E) both enhance flavor and promote fermentation.
8) Why is the pasta you buy from the grocery store shelf considered a nonperishable food?
A) It has a low nutritional content.
B) It was sterilized during preparation.
C) The low moisture content prevents microbial growth.
D) Various preservative chemicals are added.
E) Microbes present in the pasta inhibit the growth of harmful microbes.
9) Which of the following pairs is MISMATCHED?
A) vodka; potatoes
B) white wine; must
C) whiskey; cereal grains
D) beer; malt
E) brandy; fruit juice
10) Which of the following results when ethanol is allowed to oxidize to acetic acid following
the fermentation of fruit, grain, or vegetables?
A) beer
B) wine
C) whey
D) vinegar
E) must
11) Which of the following items that are commonly added during food preparation can be
considered a preservative?
A) apple juice
B) meat broth
C) garlic
D) yeast
E) whey
12) Which of the following is considered an intrinsic factor for food spoilage?
A) degree of processing
B) acidity
C) storage temperature
D) water content
E) storage packaging
13) Pickling is an effective means of food preservation involving
A) increasing pH.
B) increasing salt concentration.
C) reducing pH.
D) increasing both salt concentration and pH.
E) increasing salt concentration or reducing pH or both.
14) Which of the following is the correct sequence of steps for beer preparation?
A) mashing, malting, fermentation, clarification, aging
B) malting, mashing, adding hops, fermentation, aging
C) mashing, malting, fermenting, aging, clarification
D) malting, fermenting, adding hops, clarification, aging
15) Which of the following additives help preserve food as well as enhancing flavor?
A) cinnamon
B) garlic
C) salt
D) salt and pepper
E) cinnamon, garlic, and salt
16) Which of the following methods of preserving food sterilizes it?
A) canning
B) pasteurization
C) drying
D) gamma radiation
E) lyophilization
17) Secondary metabolites are often useful, and are obtained by
A) harvesting a culture during log phase.
B) allowing a culture to enter stationary phase.
C) growing a culture at sub-optimal temperature.
D) adding chemicals that alter metabolic pathways.
E) using continuous flow culturing.
18) Which of the following is a eukaryote involved in foodborne illness?
A) Toxoplasma gondii
B) Campylobacter jejuni
C) Listeria monocytogenes
D) Yersinia enterocolitica
E) Naegleria fowleri
19) Which of the following microorganisms associated with food poisoning thrives in cold
storage?
A) Salmonella spp.
B) Shigella spp.
C) Clostridium botulinum
D) Escherichia coli
E) Listeria monocytogenes
20) Which of the following pairs of industrial microbial products and their uses is
MISMATCHED?
A) streptokinase; dissolving blood clots
B) indigo; blue jeans
C) citric acid; antioxidant in food
D) gluconic acid; release of cellulose from flax to make linen
E) phenylalanine; the sweetener aspartame
21) Which of these microbial products is needed to produce “gasohol”?
A) citric acid
B) methanol
C) ethanol
D) hyaluronidase
E) aspartame
22) What was the first substance produced by microorganisms to be used pharmaceutically?
A) penicillin
B) streptokinase
C) phenylalanine
D) rennin
E) erythromycin
23) Industrial fermentation and fermentation in food production
A) are both processes in which sugars are oxidized to alcohols or acids.
B) are processes in which sugar or protein is oxidized to produce alcohols or acids.
C) use entirely different microorganisms.
D) use entirely different starting material.
E) make use of entirely the same microorganisms.
24) During treatment of water to make it potable, about 90% of the microbes are removed
A) by preliminary fermentation.
B) in the sedimentation step.
C) by treatment with biosensors.
D) by treatment with chlorine or ozone.
E) in the filtration step.
25) Potable water is water that
A) is considered safe to drink because it is completely sterile.
B) contains biosensors.
C) contains a dangerous number of microorganisms.
D) is transferred from one place to another.
E) contains low amounts of microorganisms and is considered safe to drink.
26) Municipal water treated with chlorine compounds contains
A) no viruses.
B) no bacteria at all.
C) no endospores.
D) no cysts.
E) a decreased microbial load.
27) Which of the following is a waterborne pathogen that causes severe diarrhea?
A) Entamoeba histolytica
B) Naegleria fowleri
C) Campylobacter jejuni
D) Toxoplasma gondii
E) Gonyaulax species
28) A patient is brought to the emergency room in a comatose state. The family reports he had
complained of nausea and a bad headache in the past couple of days. They also report they had
engaged in their normal summer activities: picnicking, fishing and swimming at the lake near
their home. His fever is high, and while in the ER, he has a seizure. Which of the following is
likely to be responsible for his symptoms?
A) Entamoeba histolytica
B) Giardia intestinalis
C) Gonyaulax
D) Naegleria fowleri
E) Toxoplasma gondii
29) Which of the following is a specific example of bioremediation?
A) the purification of water for drinking
B) the treatment of wastewater
C) the treatment of sludge
D) the degradation of crude oil spilled into the Gulf of Mexico
E) acid mine drainage
30) Which of the following is a microbial product used to reduce crop damage?
A) Bt toxin
B) saxitoxin
C) ice-minus
D) both Bt toxin and ice-minus
E) both Bt toxin and saxitoxin
31) A new industrial park in your community dumps its wastewater into a large aerated pond,
to which nutrients are added. The water from this pond makes its way into a nearby marsh,
which eventually drains into a slow-moving stream. This is an example of
A) artificial bioremediation.
B) natural bioremediation.
C) bioreporter use.
D) natural fermentation.
E) a method to make potable water.
32) A measure of wastewater treatment is its BOD. This measures the
A) biological organism density.
B) biphosphate oxidizing demand.
C) bacterial optimal density.
D) biochemical oxygen demand.
E) bioparticulate optical density.
33) Which aquatic zone in a lake will have the highest nutrient levels and therefore the densest
microbial populations?
A) the littoral zone
B) the limnetic zone
C) the profundal zone
D) the benthic zone
E) the sediment zone
34) Which of the following sets of characteristics describes the highest level of threat potential
from biological weapons?
A) a waterborne toxin that is easily introduced into public water supplies and does not replicate
in humans
B) a pathogen of livestock transmitted by contact with infected animals but not infected people
C) a human pathogen easily produced as an aerosol and transmissible by respiratory aerosols
D) a pathogen of wheat that could be delivered using crop dusters
E) a microbe that can be introduced into food during packaging and withstands refrigerator
temperatures but not typical cooking temperatures
35) Which of the following infectious diseases currently tops the list of bioterrorist threats?
A) anthrax
B) the plague
C) smallpox
D) botulism
E) cholera
36) Which of the following human diseases may result from exposure to soil containing the
microbe responsible?
A) blastomycosis
B) giardiasis
C) crown gall disease
D) cryptosporidiosis
E) saxitoxin poisoning
37) Which of the following may result from eating tuna sashimi (raw fish)?
A) botulism
B) norovirus infection
C) polio
D) salmonellosis
E) saxitoxin intoxication
38) Which of the following bacteria is a common soil contaminant that may cause disease in
humans?
A) Aspergillus oryzae
B) Bacillus anthracis
C) Cyanobacteria
D) Lactoccocus cremoris
E) Streptomyces scabies
39) Microbial proteases are used
A) in the production of linen.
B) as preservatives.
C) in spot removers.
D) as a component of fabric dyes.
E) to biodegrade plastics.
40) Streptokinase is involved in which of the following?
A) producing antibiotics
B) cheese production
C) biosensors
D) dissolving blood clots
E) insecticide
41) Which of the following is a common source of antibiotics?
A) Acetobacter
B) Bacillus species
C) Pseudomonas
D) Streptococcus thermophilus
E) Streptomyces
42) Which of the following would be most effective in reducing the amount of CO2 in the
atmosphere?
A) cyanobacteria
B) anaerobic microbes
C) heterotrophic organisms
D) fungi
E) nitrogen fixers
43) Which of the following is a nitrogen-fixing bacterium that forms associations with the roots
of plants?
A) anaerobic Bacillus species
B) Clostridium species
C) Rhizobium species
D) Azotobacter species
E) cyanobacteria
44) When runoff containing excessive nutrients enters streams and lakes it can result in an
overgrowth of cyanobacteria and algae, a process known as
A) eutrophication.
B) oxidation.
C) fixation.
D) ammonification.
E) both ammonification and fixation.
26.2 True/False Questions
1) Reducing the water content of food is a highly effective way of reducing food spoilage.
2) Canned foods are prepared using the same temperature as is used for autoclaving.
3) Amino acid and vitamin supplements are prepared from extracts of microbial cultures.
4) Pasteurization is a more rigorous process than canning.
5) Cold is preferred for storing food because it retards microbial growth by slowing down
metabolic processes.
6) Algae and protozoa in the soil are quite hardy, and therefore their abundance is not a useful
indicator of environmental pollution.
7) Through recombinant DNA technology, many plants now can manufacture their own Bt
toxin, which improves fermentation.
8) Bioremediation is the process of using organisms to clean up toxic, hazardous compounds by
degrading them to less harmful substances.
9) Without the activities of microorganisms, the functioning of Earth’s ecosystems would cease.
10) Most of the nitrogen in the environment is in the form of nitrogen gas, which is the form
used by most organisms.
26.3 Short Answer Questions
1) The definition of (fermentation/cultivation) used by food microbiologists is the desirable
change in food due to microbial activity.
2) The milk product known as (curd/yogurt/whey) is the basis of cheese production.
3) The sour flavor in some fermented foods is usually the result of (acetic/benzoid/lactic) acid
production.
4) The process of preserving foods in brine is called (canning/pickling/salting).
5) Garlic contains an antimicrobial substance called (acetic acid/allicin/benzoic acid).
6) A few hours after a dinner party, most of the people who attended begin to suffer nausea,
vomiting, and diarrhea. The food at the meal is suspected as the source, although no unusual
microbes are cultured from samples of the food or from stool samples. These observations
suggest they may be suffering from food (infection/intoxication).
7) Brandy is made by the same process as wine, but the alcohol is then concentrated by
(fermentation/distillation/filtration).
8) Freezing food and then using a vacuum to draw off the ice crystals is called
(dehydration/lyophilization/sublimation).
9) Benzoic acid is largely a(n) (antifungal/antiprotozoal/pickling) agent and does not affect the
growth of many bacteria.
10) The enzyme (amylase/hyaluronidase/lipase) can be used in injected medications to enhance
their rate of absorbance.
11) With the (batch/continuous) production technique, organisms are allowed to ferment their
substrate until it is exhausted.
12) Botryococcus braunii is an alga that produces hydrocarbons at (10/20/30) percent of its dry
weight and could be harvested in the future as an alternative fuel.
13) The anthrax attack of fall 2001 was accomplished by mailing the agent in ordinary
envelopes. This method of delivery took advantage of the ability of Bacillus anthracis to
produce (aerosols/endospores/spores).
14) When one microbe’s metabolic activities create favorable conditions for another
microorganism, this is referred to as (competition/cooperation/facilitation).
15) The organic material found in topsoil is called (humus/peat/compost).
26.4 Essay Questions
1) What are the levels of microbial associations in the environment? How do they relate to an
ecosystem?
2) Compare the use of biosensors with traditional methods of determining microbial
contamination.
3) How does water quality testing make use of environmental microbiology?
4) Smallpox is considered a serious potential biological weapon, whereas anthrax has been
successfully used as one. Compare and contrast their potential with regard to the criteria for
assessing biological threats.
5) Compare and contrast the two types of foodborne disease.