Deck 16: The Microbiology of Food and Water

Question 1

Small protein molecules produced by a microorganism that adversely affect a closely related microorganism are called

A)siderophores.
B)bacteriocins.
C)lysozymes.
D)beta-blockers.
E)proteases.

Answer 1

B

Question 2

Vacuum packaging inhibits the growth of microbes that

A)are obligate anaerobes.
B)rely on fermentation for energy metabolism.
C)are aerotolerant anaerobes.
D)rely on aerobic respiration for growth.
E)are chemolithotrophs.

Answer 2

D

Question 3

All of the following microbes play an important role in the production of fermented milk products except for

A)Lactobacillus.
B)Leuconostoc.
C)Lactococcus.
D)Clostridium.
E)Streptococcus.

Answer 3

D

Question 4

This microorganism is often used to make fermented semi-dry sausages and salami.

A)Leuconostoc
B)Pediococcus
C)Saccharomyces
D)Aspergillus
E)Lactobacillus

Question 5

Which one of the following foods would have the highest water activity?

A)Almonds
B)Honey
C)Dried Beans
D)Apple
E)Rice

Question 6

Which one of the following is an extrinsic factor that affects that rate of food spoilage?

A)The storage temperature
B)The pH of the food
C)The skin on a fruit
D)The water content of the food
E)The nutrient content of the food

Question 7

Which one of the following foods is not a fermented milk product?

A)Swiss cheese
B)Kefir
C)Butter
D)Butter milk
E)Yogurt

Question 8

Evidence of microbial food spoilage requires the presence of at least _________ microbes per gram.

A)100
B)1000
C)10,000
D 100,000
E)1,000,000

Question 9

LTH pasteurization is a method of preservation that involves heating the liquid to _______ °C for 30 min.

A)45
B)63
C)85
D)100
E)121

Question 10

When you add salt to meat for preservation you are

A)increasing the water activity of the meat.
B)decreasing the water activity of the meat.
C)increasing the pH of the meat.
D)decreasing the pH of the meat.
E)decreasing the nutrient content of the meat.

Question 11

Lyophilization is

A)the acidification of food for long term storage.
B)a type of canning technique.
C)sun-dried food.
D)freeze-drying of food.
E)salting of food for storage.

Question 12

Most milk sold in stores today has an extended shelf life primarily because of:

A)ultra-high temperature pasteurization
B)refrigeration
C)Tyndallization
D)high temperature short term pasteurization
E)low temperature hold pasteurization

Question 13

Pickling is a preservation method that uses __________ to help preserve the food.

A)alcohol
B)acetic acid
C)ascorbic acid
D)citric acid
E)spices

Question 14

The most common disease associated with improperly canned food is

A)botulism.
B)tetanus.
C)gastroenteritis.
D)colitis.
E)stomach ulcer.

Question 15

The most common food preservation method used in US households is

A)canning.
B)curing meat.
C)refrigeration.
D)heating.
E)freeze-drying.

Question 16

The fungus Penicillium is used in the production of

A)blue cheese.
B)cheddar cheese.
C)limburger cheese.
D)American cheese.
E)Colby cheese.

Question 17

What bacterium is used in the production of Swiss cheese to give it its characteristic flavor and also the holes from carbon dioxide production?

A)Pediococcus
B)Leuconostoc
C)Propionibacterium
D)Clostridium
E)Pseudomonas

Question 18

The protease rennin is used in the production of

A)butter.
B)yogurt.
C)kefir.
D)cheese.
E)ice cream.

Question 19

Which food is most prone to xerophilic mold spoilage?

A)Apple jelly
B)Sausage
C)Lettuce
D)Salt fish
E)Ground beef

Question 20

Canning is a technique used in food preservation.The food to be canned is heated to boiling for an hour

A)in the presence of high salt.
B)under acidic conditions.
C)with a preservative added for long term storage.
D)under pressure of 10 - 15 psi.
E)and immediately chilled after boiling.

Question 21

This mold and metabolism are used in the koji stage of soy sauce production:

A)anaerobic Aspergillus strains
B)aerobic Aspergillus strains
C)aerobic Leuconostoc strains
D)anaerobic Leuconostoc strains
E)none is active in this phase

Question 22

An example of an organism that causes a foodborne infection is

A)Staphylococcus aureus.
B)Campylobacter jejuni.
C)Clostridium perfringens.
D)Clostridium botulinum.
E)Bacillus cereus.

Question 23

An MPN test where lactose-fermenting microbes have been observed is known as a:

A)Presumptive test
B)A confirmed test
C)A completed test
D)A conclusive test
E)None is a correct choice

Question 24

Staphylococcus aureus causes foodborne illness through

A)the production of an enterotoxin that contaminates prepared foods.
B)a break in the skin during food preparation.
C)the ingestion of the microbe which grows in the large intestine to produce symptoms.
D)the production of an exotoxin after ingestion of the microbe.
E)the consumption of undercooked meat.

Question 25

All of the following are goals of wastewater treatment except

A)reduction of total organic content (TOC).
B)removal of harmful pathogens.
C)enhancement of the taste of water.
D)removal of nitrogen.
E)removal of phosphorus.

Question 26

Vinegar production occurs through the oxidation of ethanol by

A)lactic acid bacteria.
B)the yeast Saccharomyces.
C)various molds.
D)acetic acid bacteria.
D)sulfate-reducing bacteria.

Question 27

The main goal of the primary treatment phase of wastewater treatment is the

A)reduction of total organic content (TOC).
B)removal of pathogenic microbes.
C)reduction of nitrogen.
D)removal of particulate matter.
E)removal of toxic chemicals.

Question 28

Anaerobic digesters at wastewater treatment plants are used to

A)reduce nitrogen and phosphorus in wastewater.
B)remove toxic organic pollutants.
C)remove potential pathogens.
D)treat wastewater effluent.
E)treat sludge and particulates collected during waste treatment.

Question 29

All of the following are processes that may be used in the treatment of drinking water except

A)filtration.
B)activated sludge digestion.
C)flocculation.
D)chlorination.
E)sedimentation.

Question 30

The fuel gas __________ is frequently recovered from anaerobic digesters at a waste treatment plant.

A)methane
B)carbon dioxide
C)hydrogen
D)nitrogen
E)argon

Question 31

Ozonation is a wastewater treatment used to

A)remove organic pollutants.
B)disinfect wastewater.
C)reduce nitrogen levels in the water.
D)remove heavy metals that may be present in wastewater.
E)remove phosphorus from wastewater.

Question 32

The activated sludge method of wastewater treatment uses

A)a microbial biofilm for organic carbon reduction.
B)an inoculum from the previous activated sludge treatment.
C)chemolithotrophic bacteria for carbon reduction.
D)special chemicals for the removal of organic pollutants.
E)large screens to filter out particulate matter.

Question 33

Staphylococcal enterotoxicosis may occur with:

A)Recently oven-removed cooked foods
B)Canned foods recently opened and then refrigerated
C)Foods in warming ovens at a buffet
D)Frozen foods like ice cream freshly served
E)All have an equal risk

Question 34

Which microbe listed below causes foodborne intoxication?

A)Shigella
B)Salmonella
C)Staphylococcus
D)Campylobacter
E)Vibrio

Question 35

Which of the following methods use microbial biofilms for secondary phase of wastewater treatment?

A)trickling filter
B)activated sludge
C)anaerobic digester
D)nitrification tank
E)oxidation pond

Question 36

The release of high levels of nitrogen and phosphorus into streams after wastewater treatment will result in

A)the production of high quality water for plant irrigation.
B)water that tastes bad.
C)eutrophication of the stream.
D)increased nutrients for the fish in the stream.
E)increase in oxygen levels in the stream.

Question 37

The most efficient production of vinegar is achieved with the:

A)trickle method
B)quick method
C)Orleans method
D)Appertiizer method
E)Frings method

Question 38

Fermented soybean products,like miso and tempeh,are produced using

A)lactic acid bacteria.
B)molds.
C)propionate bacteria.
D)acetic acid bacteria.
E)Saccharomyces.

Question 39

The ________________ is a measure of the amount of oxygen required for the microbial oxidation of organic compounds in a water source.

A)chemical oxygen demand
B)biological oxygen demand
C)respiration rate
D)carbon dioxide production
E)cell yield

Question 40

This mold and metabolism are used in the moromi stage of soy sauce production:

A)anaerobic Aspergillus strains
B)aerobic Aspergillus strains
C)aerobic Leuconostoc strains
D)anaerobic Leuconostoc strains
E)none is active in this phase

Question 41

The koji and moromi stages of soy sauce fermentation differ by these characteristics: (Select all that apply)

A)Koji is aerobic,moromi is anaerobic
B)Moromi is aerobic,koji is anaerobic
C)Koji is low-salt conditions,moromi is high-salt conditions
D)Moromi is low-salt conditions,koji is high-salt conditions
E)Koji is fermentation for several days,moromi is fermentation for several months

Question 42

In the MPN test,at which stage would the first identification of Enterobacteriaceae organisms occur?

A)Presumptive
B)Confirmed
C)Completed
D)Conclusive
E)All stages would permit this identification

Question 43

The MPN test estimates 33 potential fecal coliforms per 100 ml of sample water.Which results may have been observed? (Select all that apply)

A)Positive results in 4 in the 10ml samples,3 in the 1ml samples and 1 from the 0.1ml samples
B)Positive results in 4 in the 10ml samples,2 in the 1ml samples and 1 from the 0.1ml samples
C)Positive results in 5 in the 10ml samples,1 in the 1ml samples and 0 from the 0.1ml samples
D)Positive results in 5 in the 10ml samples,0 in the 1ml samples and 1 from the 0.1ml samples
E)Positive results in 4 in the 10ml samples,0 in the 1ml samples and 1 from the 0.1ml samples

Question 44

The MPN test generates positive tube numbers of 5 in the 10ml samples,1 in the 1ml samples and 0 from the 0.1ml samples.What is the most likely number of organisms present in the original sample?

A)33 microbes per ml
B)33 microbes per 100 ml
C)33 microbes per liter
D)43 microbes per 100 ml
E)46 microbes per ml

Question 45

In the MPN test,at which stage would the first identification of Klebsiella organisms occur?

A)Presumptive
B)Confirmed
C)Completed
D)Conclusive
E)All stages would permit this identification

Question 46

with respect to water quality,an indicator organism is one which: (Select all that apply)

A)Causes water-borne illness
B)Ferments lactose
C)Is found in the mammalian intestine
D)Forms endospores
E)Ferments glucose

Question 47

In the MPN test,at which stage would the first identification of coliforms organisms occur?

A)Presumptive
B)Confirmed
C)Completed
D)Conclusive
E)All stages would permit this identification

Question 48

At an aw of 0.93,which of these microbes might cause food spoilage? (Select all that apply)

A)Staphylococcus aureus
B)E)coli
C)Xerophilic molds
D)Osmophilic microbes
E)Pseudomonas

Question 49

Which set of conditions will most effectively removed nitrogen containing compounds from wastewater to reduce eutrophication?

A)Aerobic conditions with addition of nitrifiers and denitrifiers
B)Anaerobic conditions with addition of nitrifiers and denitrifiers
C)Aerobic conditions with addition of nitrifiers and annamox bacteria
D)Anaerobic conditions with addition of denitrifiers and annamox bacteria
E)Anaerobic conditions with addition of denitrifiers and annamox bacteria

Question 50

with respect to water quality,an indicator organism is one which: (Select all that apply)

A)Causes little,if any,illness
B)Ferments lactose to produce gas
C)Is found in the avian intestine
D)Is non-endospore forming
E)Grows well at temperatures of 25 degrees C

Question 51

In the MPN test,at which stage would the first identification of lactose fermenting organisms occur?

A)Presumptive
B)Confirmed
C)Completed
D)Conclusive
E)All stages would permit this identification

Question 52

An MPN test where a positive EMB test (presence of metallic green colonies)has been observed is known as a:

A)Presumptive test
B)A confirmed test
C)A completed test
D)A conclusive test
E)None is a correct choice

Question 53

The koji and moromi stages of soy sauce fermentation differ by these characteristics: (Select all that apply)

A)Koji is high-temperature,moromi is low-temerature
B)Moromi is low-temerature,koji is high-temperature
C)Koji is low-salt conditions,moromi is high-salt conditions
D)Moromi is low-salt conditions,koji is high-salt conditions
E)Koji is fermentation for several months,moromi is fermentation for several days

Question 54

Which of the following type of radiation may be used to sterilize food? (Select all that apply)

A)Long wavelength ultra-violet
B)Short wavelength ultra-violet
C)Gamma irradiation
D)Ionizing
E)Infrared

Question 55

At an aw of 0.80,which of these microbes might cause food spoilage? (Select all that apply)

A)Staphylococcus aureus
B)E)coli
C)Typical molds
D)Osmophilic microbes
E)Pseudomonas

Question 56

The MPN test estimates 34 potential fecal coliforms per 100 ml of sample water.Which results may have been observed? (Select all that apply)

A)Positive results in 4 in the 10ml samples,3 in the 1ml samples and 1 from the 0.1ml samples
B)Positive results in 4 in the 10ml samples,2 in the 1ml samples and 1 from the 0.1ml samples
C)Positive results in 5 in the 10ml samples,1 in the 1ml samples and 0 from the 0.1ml samples
D)Positive results in 5 in the 10ml samples,0 in the 1ml samples and 1 from the 0.1ml samples
E)Positive results in 4 in the 10ml samples,4 in the 1ml samples and 0 from the 0.1ml samples

Question 57

An MPN test where E.coli bacteria have been identified is known as :

A)A presumptive test
B)A confirmed test
C)A completed test
D)A conclusive test
E)None is a correct choice

Question 58

The MPN test generates positive tube numbers of 4 in the 10ml samples,3 in the 1ml samples and 0 from the 0.1ml samples.What is the most likely number of organisms present in the original sample?

A)33 microbes per ml
B)20 microbes per 100 ml
C)33 microbes per liter
D)27 microbes per 100 ml
E)46 microbes per ml

Question 59

Foods with high water activity will usually spoil faster than foods with a low water activity.

Question 60

Hurdle preservative technology permits:

A)Reduced acidification of foods
B)Increased acidification of foods
C)Reduced heat treatment of food
D)Increased heat treatment of food
E)Reduced aw of food

Question 61

Chemical food preservatives like sodium benzoate,acetic acid,and propionate can only be used to protect alkaline foods.

Question 62

Vinegar is made by bacteria from one of two genera,either Gluconobacter or ________________.

Question 63

The addition of salt to certain food for preservation has been used for hundreds of years.Salt helps to preserve food by lowering the water activity.

Question 64

The bacterium that gives Swiss cheese its characteristic flavor and holes is in the genus ____________.

Question 65

A person eats some leftover potato salad from a picnic and becomes ill within three hours.This type of food poisoning is referred to as a "food-infection".

Question 66

One of the main reasons for wastewater treatment is to reduce the BOD.