Microbiology Test 3: Chapter 16 practice questions

This type of foodborne illness typically presents quickly after consumption of affected food. Foodborne intoxication Foodborne infection Foodborne poisoning

Foodborne intoxication

The principle behind canning as an effective means of food preservation is -it reduces available water content (aw). -exposure to high temperatures under pressure for an extended period of time reduces the number of potential spoilage organisms. -limiting exposure to the atmosphere by storage in a sealed container reduces the potential of contamination by spoilage organisms. -the chemical additives used during the canning process will significantly lower the pH and inhibit the growth of potential spoilage organisms.

exposure to high temperatures under pressure for an extended period of time reduces the number of potential spoilage organisms.

Typically, agents of foodborne illnesses target the nervous system. gastrointestinal tract. respiratory system. musculoskeletal system.

gastrointestinal tract.

In the world of wastewater treatment, biosolid is defined as -suspended material heavier than water. -stabilized sludge. -clumps of biomass consisting of adsorbed material and biofilm microorganisms. -filtered organic concentrate.

stabilized sludge.

Natural sources of water, unimpacted by humans, typically have very low microbial populations. True False

False

Fun Fact: The estimated number of foodborne illnesses in the USA in 2011 was 48,000. 480,000. 4,800,000. 48,000,000.

48,000,000.

Why is one type of cheese different from another? -The temperature at which fermentation is carried out. -The length of time fermentation is allowed to proceed. -The species and concentration of starter culture used for fermentation. -The pH of whey when it is separated from the curds.

The species and concentration of starter culture used for fermentation.

Why are lactic acid bacteria (LAB) of special significance in the food industry? -They are the only group that can metabolize a wide variety of sugar substrates. -They are the only group that can ferment within feasible ranges of pH and temperature. -This group happens to produce metabolic end products with desirable taste properties. -They are inexpensive to grow in large quantities.

This group happens to produce metabolic end products with desirable taste properties.

"Commercial sterility" is not the same thing as absolute sterility. True False

True

Fresh foods are characterized by a high aw and preserved foods often have a low aw. True False

True

In addition to reducing the microbial load and eliminating potential pathogens, wastewater treatment systems are able to reduce the nitrogen and phosphorus loads, thus improving water quality. True False

True

In western countries, most lactic acid bacteria and yeasts are the primary fermenters, but in Asian countries, molds are the primary fermenters. True False

True

Lyophilization is a fancy name for freeze-drying. True False

True

Manipulating pH is an effective means of preserving foods. True False

True

Potable water is water suitable for drinking. True False

True

Phage infections in starter cultures are a source of constant concern for dairy processors. What is a strategy used to limit the impact of phages in starter cultures? -Use good aseptic technique. -Use media that supports the growth of large numbers of starter culture cells. -Use starter cultures without phages. -All of these choices.

Use good aseptic technique.

A food with an aw of 0.75 is best refrigerated to extend shelf life. stable at room temperature and has a long shelf life. a potential host for spoilage by bacteria. a potential host for spoilage by molds.

a potential host for spoilage by molds.

An advantage of using starter cultures instead of relying on the microbes found naturally in the raw material is -the starter cultures yield much more consistent products. -the naturally occurring microbes may not be present in sufficient numbers to be commercially viable. -the starter cultures can be maintained more cost effectively. -all of these choices.

all of these choices.

When examining bacterial growth curves to determine which microbes may be potential spoilage organisms, the component of the curve of most interest is the lag phase. the exponential phase. the stationary phase. both the lag phase and the exponential phase.

both the lag phase and the exponential phase.

In the world of wastewater treatment, floc is defined as -suspended material heavier than water. -stabilized sludge. -clumps of biomass consisting of adsorbed material and biofilm microorganisms. -filtered organic concentrate.

clumps of biomass consisting of adsorbed material and biofilm microorganisms.

The principle behind pasteurization as a mechanism to prevent food spoilage is -only very small, non-spoilage microbes are able to pass through the biological filters. -it reduces available water content (aw). -exposure to short bursts of high heat, pressure, or irradiation destroys most microbes without cooking the food. -limiting exposure to the atmosphere by storage in a sealed container reduces the potential of contamination by spoilage organisms.

exposure to short bursts of high heat, pressure, or irradiation destroys most microbes without cooking the food.

Non-perishable foods are often non-perishable because they have been sterilized. are naturally sterile. have very limited organic content. have limited water availability.

have limited water availability.

The impact of refrigeration on the growth curve of potential spoilage bacteria is -it extends the lag time. -it increases the rate of exponential growth. -it increases the number of cells necessary to reach the stationary phase. -it extends the lag time and increases the number of cells necessary to reach the stationary phase.

it extends the lag time.

At the conclusion of the primary treatment stage, and prior to start of the secondary treatment stage, the effluent is -sterile. -not sterile, but with reduced microbial load. -not sterile, but with reduced microbial load and a high percentage of suspended solids. -not sterile, but with concentrated microbial load and a low percentage of suspended solids.

not sterile, but with reduced microbial load and a high percentage of suspended solids.

The best way to reduce the risk of foodborne illness is to use organic products. prepare and store food at appropriate temperatures. eat only a liquid diet. thoroughly wash all food before preparation.

prepare and store food at appropriate temperatures.

Modified atmosphere package (MAP) helps to preserve food by removing oxygen from the atmosphere. removing water vapor from the atmosphere. removing carbon dioxide from the atmosphere. all of these choices.

removing oxygen from the atmosphere.

A limitation of freezing as a food preservation mechanism is -the formation of ice crystals which puncture cells and negatively impact the texture of the food. -most foods can only be frozen for relatively short periods of time. -long term freezing changes the pH of many foods. -none of these choices; there are no serious drawbacks to freezing as a food preservation mechanism.

the formation of ice crystals which puncture cells and negatively impact the texture of the food.

The principle behind irradiation as a mechanism to prevent food spoilage is -only very small, non-spoilage microbes are able to survive exposure to radiation. -it reduces available water content (aw). -the nucleic acid of living cells is damaged, resulting in the death of any potential food spoilage microbes. -radioactive cells are not able to reproduce properly.

the nucleic acid of living cells is damaged, resulting in the death of any potential food spoilage microbes.

Taste consistency for fermented products is achieved by mixing multiple batches of product. using reliable starter cultures. intensive testing at multiple points in the fermentation process. consistently using raw materials from the same sources.

using reliable starter cultures.