Chapter 41
Pasteurization is the use of heat to kill both pathogens and spoilage organisms. It's commonly used for treatment of milk. For the high-temperature, short-time (HTST) process, milk is treated at ________.
72oC for 15 seconds
Which of the following is a nucleic acid-based method used to test foods for pathogens?
All of the options listed are nucleic acid-based methods of testing food for pathogens.
A major fungal genus that produces aflatoxin is _________.
Aspergillus
Beer making is a process by which cereal grains are used and fermented into an alcoholic beverage. Arrange the text in the proper order to review the steps of the beer making process.
Barley moistening and germination Drying and crushing Mashing Add hops Heat in brew kettle Add yeast Fermentation Storage (lagering) packageing
Which of the following statements is false regarding the control of microbial growth by altering the availability of water?
Foods with a high sugar content such as honey, jams and jellies, and syrup, have a high aw value, which eliminates the growth of microbes.
Wine making is a process by which juice from a fruit is fermented into an alcoholic beverage. Arrange the text in the proper order to to review the steps of the wine making process.
Grape pressing Sterilization; yeast addition Fermentation of must Setting vat Aging Bottling
How does high-oxygen modified atmosphere packaging preserve food?
It stimulates the formation of radical oxygen species in contaminating microorganisms
Identify a microorganism used in probiotic food.
Lactobacillus
Which of the following is most often used as a starter culture for the production of cheese?
Lactobacillus species
One of the largest meat recall in U.S. history was prompted by the discovery of contamination by _________.
Listeria monocytogenes
Cheese and beer are examples of fermented foods commonly consumed in the United States, but there are many other fermented foods consumed around the world. Identify the fermented foods from the ones listed below. (Check all that apply.)
Miso, Kimchi, Tempeh
Your roommate made potato salad and then let it sit on the counter overnight, forgetting to refrigerate it. When she discovered it in the morning, she asked you whether you thought it would be safe to eat. How should you reply?
No, because refrigeration will not inactivate microbial toxins that may have been produced while the salad sat at room temperature.
A major organism considered to cause food-borne infection is _________.
Salmonella
Food-borne illnesses can have substantial health and economic consequences. Correctly identify the steps that can lead to food-borne illness by Salmonella/Campylobacter and E. coli O157:H7.
Salmonella/Campylobacter-Incomplete cooking of poultry and fruits/vegetables fails to kill all pathogens, Live Salmonella or Campylobacter bacteria are ingested, The pathogen multiplies in the intestinal tract for 2-48 days, Diarrhea, abdominal pain, and nausea can result E. coli- Incomplete cooking of raw hamburger fails to kill all pathogens, Live E. coli O157:H7 bacteria are ingested, A Shiga-like toxin is produced, Bloody diarrhea and hemolytic uremic syndrome can result
Which of the following determines whether or not a wine is considered to be dry?
The amount of free sugar after fermentation
Your friend tells you that she is lactose intolerant, but can eat yogurt without developing the cramps and bloating that other dairy products trigger. Why is this the case?
The bacteria in yogurt ferment almost all of the lactose to lactate
Why aren't foods tested for every potential pathogen before sale?
The practice is cost-prohibitive
Pasteurization of milk _________.
Usually eliminates all disease-causing organisms
The process of beer lagering involves _________.
aging
Nisin _________.
all of the choices are correct
The difference between aflatoxins and fumonisins is that __________.
all of the choices are correct
Which of the following helps preserve foods by controlling microbial access to water?
all of the choices are correct
Which of the following microbial genera is used in the production of fermented dairy products?
all of the choices are correct
Which of the following represents ways in which canned foods may undergo spoilage?
all of the choices are correct
Yet another use of heat is the sterilization of closed anaerobic containers in the ________ process.
canning
Mashing is a process involving _________.
carbohydrate hydrolysis
The swelling of a food-containing can is frequently due to the production of _______ by spoilage microbes.
carbon dioxide gas
The production of natural carbon dioxide by yeasts after a wine is bottled results in ________.
champagne
Lysozyme is an important antimicrobial substance found at high levels in which food?
eggs
The ripening process during cheese production _________.
employs metabolic activities of other microbes to produce texture and flavor changes in the cheese over time
The science of wine production is called ________.
enology
Microbial growth can be controlled by both intrinsic and extrinsic factors. Classify each characteristic by category.
extrinsic- storage temperature, packaging, humidity intrinsic- amount of carbs, presence of a rind, oxidation-reduction potential, water activity
When food supplies, such as beef and pork, are gamma irradiated to kill pathogenic organisms, the food becomes temporarily radioactive. There is no harm to humans because the effects have worn off by the time the meat reaches grocery store shelves.
false
The term radappertization is used to describe food preservation by _________.
gamma irradiation
The Centers for Disease Control and Prevention (CDC) program PulseNet uses _________.
genomic fragments that have been generated by restriction endonucleases
Which of the following represents a different principle for food preservation?
heating
Clostridium botulinum and Bacillus cereus are important disease causing microorganisms of food that cause _________.
intoxications
Low temperature holding (LTH) pasteurization, commonly used to treat milk, beer, and fruit juices, heats the liquid for ________.
minutes
Gamma irradiation has been used to sterilize certain types of foods. There are, however, certain limitations on its effectiveness. One of these is that it will only work on _________.
moist food
A major chemical used to preserve meat products is ________.
nitrite
The use of plastic film to wrap meat products can result in increased surface growth of microorganisms in part because of exposure to _________.
oxygen
This process was advanced in the case of milk _____________, where slightly lower temperatures are applied yet still effective in killing potential pathogens.
pasteurization
On the other hand, low temperatures used in __________ or freezing inhibit the growth of most microorganisms, but do not kill the microbes.
refrigeration
A variety of meat products are produced by fermentation. What are examples of fermented meat products? (Check all that apply.)
salami, fish sauce, country-cured ham
Various chemicals are used to preserve food and prevent microbial spoilage. If you wanted to prevent Clostridium botulinum spore germination in your sausage meat, it would be best to use ________.
sodium nitrite
The Food and Drug Administration uses the acronym "GRAS" to describe chemical preservatives. The ambiguity of the term "generally recognized as safe" may be questionable in light of the fact that __________.
sodium nitrite is toxic in animals and humans, and poses a probable cancer risk when combined with amines found in high-protein foods such as fish, fermented foods such as cheese and wine, as well as certain fruits and vegetables
A chemical that is effective in preserving foods with a low pH such as bread is ________.
sodium propionate
You have been hired by a bakery to help package cakes and cookies for sale throughout your state. You recognize that these foods are high in carbohydrates. You could, therefore, recognize spoilage by which of the following changes in the products?
souring
Foods can be spoiled by both intrinsic and extrinsic factors. Extrinsic factors can include things such as ________.
storage temperature
To control microbial growth in a food, one can decrease water availability by the addition of ________.
sugar or salt
Another ancient method is the use of high _________ when cooking to kill many microbes present in food.
temperature
Preservation of fermented meat products is accomplished by _________.
the lower pH and lower water activity
Gamma irradiation is used on a variety of foods to extend their shelf life. Some of the characteristics of irradiation are ______. (Check all that apply.)
the process must be used with moist foods an effective way to sterilize food
A mold-lactic fermentation is used to produce ________.
viili
Many common methods of food preservation have been utlilized since ancient times, such as salting, which lowers __________ and inhibits microbial growth.
water activity
Currently, the CDC's PulseNet program is in operation to track food-borne pathogens back to their source. Thanks to efficiency and lower costs, this program is likely to be replaced by __________.
whole-genome sequencing
Which of the following can function better at lower pH?
yeasts and molds
Microbes can produce food-borne toxins that cause illness upon ingestion. Fungal-derived toxins include aflatoxin and fumonisins. Classify characteristics of each fungally derived toxin type.
aflatoxins- produced in nut products, caused by aspergillus flavus, act as frameshift mutagens fumonisins- produced in corn, caused by Fusarium moniliforme, inhibit a key host enzyme
