Ch. 28 Microbiology
Commercial sterilization of processed canned foods uses 12D treatment which is based upon theoretical population of 10^12 C. botulinum endospores in a can of food. After treatment, there would theoretically be how many endospores left? a. 100 endospores b. 1 endospore c. 10 endospores d. 12 endospores c. 0 endospores
1 endospore
Bioreactors are widely used for industrial fermentation. Which of the following conditiona must be closely monitored for optimal fermentation? a. pH b. oxygen levels c. temperature d. both temperature and pH e. temperature, pH, and oxygen levels
temperature, pH, and oxygen levels
All of the following are industrial products produced by microbes EXCEPT a. antibiotics b. industrial enzymes c. amino acids in food supplements d. vitamin B12 and riboflavin e. uranium
uranium
All of the following are industrial enzymes made by microbial fermentations EXCEPT a. vitamin C b. amylases c. rennin d. proteases e. glucose isomerase
vitamin C
Commercial sterilization differs from complete sterilization in that commercial sterilization a. kills all microorganisms b. employs a higher temperature c. kills only bacteria d. may result in the survival of thermophiles e. may result in the survival of fungal spores
May result in the survival of thermophiles
What will be produced if wine is aerated? a. ethanol + CO2 b. acetic acid c. CH4 d. CO2 + H2O e. none of these answers is correct
acetic acid
Microorganisms play an active role in the formation of industrial products. Which of the following is mismatched? a. penicillium--treatment of disease b. Rhizobium--increases nitrogen in the soil c. algae--citric acid d. Bacillus thuringiensis--insecticide e. Saccharomyces cerevisiae--for fermenation
algae--citric acid
Canning works to preserve foods through a. exposure to heat b. creation of an anaerobic environment c. increasing pH d. mutation of bacterial DNA e. creation of an anaerobic environment and high heat
creation of an anaerobic environment and high heat
Aseptic packaging works to preserve foods through a. increasing pH b. creation of an anaerobic environment and high heat c. mutation of bacterial DNA d. exposure to high heat e. creation of an anaerobic environment
exposure to high heat
Figure 28.3 shows the growth curves of Acetobacter under different conditions. Which culture would produce the highest amount of the primary metabolite acetic acid? A. a B. b C. c D. d E. e
A. a
Which of the following is an undesirable contaminant in wine making? a. Acetobacter b. Clostridium c. Saccharomyces d. lactic acid bacteria e. Bacillus
Acetobacter
In figure 28.1, assume the cells are your desired product and you want to maintain a continuous culture. When would you harvest cells to maximize your yield? A. a B. b C. c D. d
B. b
Which of the following microbes produces a natural biopesticide? a. Bacillus thuringiensis b. penicillium chryssogenum c. Saccharomyces cerevisiae d. Lactobacillus buggaricus e. Thiobacillus ferroxidans
Bacillus thurngiensis
Which of the following pair is mismatched a. lactobacillus--yogurt b. Bacillus--Beer c. penicillium--blue cheese d. propionibacterium--Swiss cheese e. acetobacter--vinegar
Bacillus--Beer
In figure 28.1, assume the cells are producing penicillin which is collected during the idiophase. When would you be able to collect the penicillin? A. a B. b C. c D. d
C.
In figure 28.1, assume that the secondary metabolite is your desired product. When would you be able to obtain it? A. a B. b C. c D. d
C. c
Which of the growth curves in figure 28.3 will give the highest yield of a secondary metabolite? A. a B. b C. c D. d E. e
C. c
Spoilage of canned foods due to inadequate processing, NOT accompanied by gas production, is a. putrefactive anaerobic spoilage b. spoilage by mesophilic bacteria c. flat sour spoilage d. thermophilic anaerobic spoilage e. caused by acid-tolerant fungi
Flat sour spoilage
Which of the following microorganisms is usually used in the fermentation of alcoholic beverages? a. Lactobacillus b. Rhizopus c. Penicillium d. Saccharomyces e. Propionobacterium
Saccharomyces
Which of the following reactions is performed by yeast in wine-making? a. carbon dioxide-->sucrose b. sugar--CO2 + H2O c. malic acid--> lactic acid d. sugar--ethanol e. ethanol--acetic acid
Sugar--> ethanol
A baker forgets to put yeast in his bread dough. Which of the following do you expect to happen to the bread as a result? a. the bread will have a sour taste b. it will take longer to bake c. bacterial contaminants will now be able to grow d. the bread will not rise e. the bread will look normal but will be tough
The bread will not rise
Spoilage of canned foods stored at high temperatures, accompanied by gas production is a. putrefactive anaerobic spoilage b. spoilage by mesophilic bacteria c. flat sour spoilage d. thermophilic anaerobic spoilage e. caused by acid-tolerant fungi
Thermophilic anaerobic spoilage
All of the following are reasons for utilizing algae for biofuel production EXCEPT a. they produce more energy per acre than corn b. they produce a non-degradable waste product c. they do not take up land needed for food production d. their main requirement is abundant light e. they can utilize poor land
They can produce non-degradable waste product
Microorganisms themselves are commercial products. Which of the following microbes is available as a product sold in retail stores? a. Rhizobium b. Lactobacillus c. Bacillus thuringiensis d. saccharomyces e. all of these organisms can be found in various commercial products
all of these organisms can be found in various commercial products
Canning preserves food a. by exposure to chemicals b. by exposure to high pH c. by exposure to radiation d. through use of aseptic packaging e. by exposure to high heat
by exposure to high heat
All of the following are fuels produced by microorganisms EXCEPT a. hydrogen b. ethanol c. cellulose d. oil from algae e. methane
cellulose
Thiobacillus ferrooxidans is used for the recovery of ____ from ore a. sulfur b. iron c. sulfuric acid d. gold e. copper
copper
What process does yeast use to produce ethanol for automobile fuel from corn? a. the krebs cycle b. oxidation c. anaerobic respiration d. fermentation e. photosynthesis
fermentation
You are growing Bacillus subtilis in a bioreactor and notice that the growth rate has slowed and the pH has decreased. you suspect the bacteria are a. using the krebs cyle b. dead c. using proteins d. photosynthesizing e. fermenting
fermenting
All of the following are uses for radiation EXCEPT a. prevention of spouting b. killing of insect eggs and larva c. inactivation of Trichinella larvae d. sterilizing spices e. heating cold food
heating cold food
Aseptic packaging utilizes which of the following to sterilize laminated paper or plastic prior to filling with food? a. X rays b. hot hydrogen peroxide solution c. autoclave d. gamma radiation e. hot HCI solution
hot hydrogen peroxide solution
The following steps are required for making cheese. What is the second step? a. separation of curds and whey b. enzymatic coagulation of milk c. fermentation of curd d. inoculation with lactic acid bacteria e. inoculation with penicillium
inoculation with lactic acid bacteria
All of the following foods are produced using microbial fermentations EXCEPT a. sauerkraut b. ketchup c. yogurt d. coffee e. sour cream
ketchup
What role do lactic acid bacteria play in cheese production? a. providing characteristic flavor and smell b. curd formation c. ripening the cheese d. production of hole in Swiss cheese e. lactic acid bacteria carry out each of these roles in cheese production
lactic acid bacteria carry out each of these roles in cheese production
Radiation works to preserve foods through a. increasing pH b. exposure to high heat c. creation of an anaerobic environment and high heat d. creation of anaerobic environment e. lethal mutation of bacterial DNA
lethal mutation of bacterial DNA
Which of the following reactions makes wine less acidic? a. carbon dioxide-->sucrose b. sugar--CO2 + H2O c. malic acid--> lactic acid d. sugar--ethanol e. ethanol--acetic acid
malic acid--> lactic acid
Which of the following pertains to an improperly canned food product on a store shelf that bulges from microbial activity? a. mesophilic spoilage b. hydrogen sulfide spoilage c. flat sour spoilage d. thermophilic anaerobic spoilage e. bacterial soft rot
mesophilic spoilage
As cheese ages, it gets a. saltier b. more alcoholic c. more protein d. more acidic e. more whey
more acidic
All of the following are advantages of a bioreactor instead of a flask culture EXCEPT a. instrumentation for monitoring environmental conditions b. larger culture volumes can be grown c. uniform aeration and mixing d. aseptic sampling e. none of the answers is correct; all of these are advantages of using a bioreactor instead of a flask culture
none of the answers are correct
Biomass is a renewable energy source derived from the organic matter produced by living organisms. All of the following are sources of biomass EXCEPT a. bacteria b. oxidation of metals c. landfill sites d. algae e. crops
oxidation of metals
You are growing Bacillus subtilis in a bioreactor and notice that the growth rate has slowed and the pH has decreased. What could you add? a. lactose b. lactic acid c. glucose d. oxygen e. peptides
oxygen
All of the following are true of irradiation methods used for food production and sterilization except a. they are used for sterilization of many species b. they greatly reduce the number of pathogens present in meats and poultry c. they prolong shelf-life of fruits and vegetables d. ionizing radiation sich as X rays or gamma rays is used e. residual radioactivity is left behind on many foods
residual radioactivity is left behind on many foods
All of the following are industrial products produced using microbial fermentation EXCEPT a. monosodium glutamate b. citric acid c. riboflavin d. aspartame e. saccharin
saccharin
Xanthan used in household products is produced by bacteria a. that were irradiated to mutate them b. that are plant pathogens c. selected for their ability to utilize lactose d. that were genetically modified e. selected for their ability to utilize lactose and that are plant pathogens
selected for their ability to utilize lactose and that are plant pathogens
Microbial products can be improved by all of the following EXCEPT a. sterilization b. isolating new strains c. mutating existing strains d. modifying culture conditions e. genetically modifying strains
sterilization