Question 1

Sometimes __________ beams are used to irradiate foods in place of gamma radiation because the process does not generate radioactive waste.

Accepted Answer

Electron beams are used to irradiate foods as an alternative to gamma radiation because they do not generate radioactive waste. This technology is known as electron beam irradiation.

Question 2

The swelling of a food-containing can is frequently due to the production of ___________ by spoilage microbes.

Accepted Answer

The production of carbon dioxide gas is a common sign of spoilage in food-containing cans, leading to the swelling of the can. Oxygen and nitrogen gases are not commonly produced by spoilage microbes. Therefore, option D is not correct.

Question 3

The conventional low-temperature holding procedure used in the pasteurization of milk involves holding the milk at 62.8^oC for __________ minutes.

Accepted Answer

The conventional low-temperature holding procedure used in the pasteurization of milk involves holding the milk at 62.8°C for 30 minutes.

Question 4

Which of the following is true about molecular methods of microorganism detection in foods?

Accepted Answer

Molecular methods of microorganism detection in foods can be used to detect a single specific pathogen, viruses that are not easily cultured, and slow-growing pathogens. Therefore, all the choices are correct.

Question 5

The process of racking,used in the production of wines,involves

Accepted Answer

The process of racking in wine production involves the removal of sediments from the wine. This is done by transferring the wine from one container to another, leaving the sediments behind in the original container.

Question 6

Food-borne pathogens are most commonly identified by

Accepted Answer

Standard culture techniques are the most commonly used method for identifying food-borne pathogens. This involves isolating the pathogen and growing it in a culture to determine its characteristics and identify it. PCR and pulsed-field gel electrophoresis are also used for identification but are typically reserved for more specialized or specific testing purposes.

Question 7

If food-borne disease transmission requires ingestion of the pathogen,followed by growth of the organism,and release of toxins in the intestine it is referred to as a food-borne __________.

Accepted Answer

The answer of If food-borne disease transmission requires ingestion of...

Question 8

Staphylococcus aureus,once it grows in a food,produces toxins that are not usually inactivated by heating.

Accepted Answer

Staphylococcus aureus can produce heat-stable enterotoxins that are not easily destroyed by cooking, so the toxins can still cause illness even if the bacteria have been killed by heat.

Question 9

Clostridium botulinum and Bacillus cereus are important disease-causing microorganisms of food which cause _________.

Accepted Answer

Both Clostridium botulinum and Bacillus cereus cause intoxications, which occur when a person eats food containing toxins produced by the microorganisms.

Question 10

A major organism considered to cause food-borne infection is

Accepted Answer

Salmonella is a major organism that causes food-borne infections. It can be found in many types of food, including poultry, eggs, and raw fruits and vegetables. Consuming contaminated food can cause symptoms such as fever, diarrhea, and abdominal cramps. It is important to properly handle and cook food to prevent the spread of Salmonella and other food-borne illnesses. Staphylococcus and Bacillus are also known to cause food-borne illnesses, but they are not considered to be as major as Salmonella. Pseudomonas is not typically associated with food-borne illnesses.

Question 11

A major fungal genus that produces aflatoxin is

Accepted Answer

The genus Aspergillus is a major producer of aflatoxin, a potent carcinogenic toxin that can contaminate food crops such as corn, peanuts, and tree nuts. Rhizopus, Claviceps, and Penicillium are fungal genera that are not known to produce aflatoxin.

Question 12

Aflatoxins are planar,ringed compounds that interact with DNA by ___________ and cause frameshift mutations.

Accepted Answer

Aflatoxins are known to intercalate into DNA, meaning they insert themselves between the base pairs. This can cause frameshift mutations, where a deletion or insertion of one or more base pairs occurs, ultimately leading to genetic damage.

Question 13

If food-borne disease transmission does not require growth of the microorganism after ingestion because the toxic substances are already present in the food as a result of previous growth,then it is referred to as a food-borne __________.

Accepted Answer

The answer of If food-borne disease transmission does not require...

Question 14

The largest meat recall in U.S.history was prompted by the discovery of contamination by

Accepted Answer

The largest meat recall in U.S. history was prompted by the discovery of contamination by Listeria monocytogenes in 2008. This recall affected over 143 million pounds of beef and was linked to numerous illnesses and deaths.

Question 15

To control microbial growth in a food,one can decrease water availability by the addition of ________.

Accepted Answer

Adding sugar or salt decreases water availability in food, which can inhibit microbial growth. Gelatin and agar are used as gelling agents in food preparation and do not necessarily inhibit microbial growth. Formaldehyde is a toxic chemical that is not used for controlling microbial growth in food.

Question 16

The process of beer lagering involves _________.

Accepted Answer

Lagering refers to the process of aging beer at low temperatures for several weeks, often in a secondary fermentation vessel. This process allows for the beer to clarify and for flavors to mellow and blend together, resulting in a smoother and crisper taste. Carbonation and distillation are not part of the lagering process.

Question 17

The polymerase chain reaction (PCR)can detect as few as 10 toxin-producing Escherichia coli in a population of 100,000 microorganisms isolated from soft cheese samples.

Accepted Answer

PCR is a highly sensitive molecular technique that can detect even small amounts of a specific pathogen in a complex mixture of microorganisms. It is capable of detecting as few as 10 bacteria in a sample, making it a powerful tool for food safety testing. Therefore, it is true that PCR can detect as few as 10 toxin-producing Escherichia coli in a population of 100,000 microorganisms isolated from soft cheese samples.

Question 18

A microorganism that has been used in the production of sour mash whiskey is _________.

Accepted Answer

The answer of A microorganism that has been used in...

Question 19

The production of natural carbon dioxide by yeasts after a wine is bottled results in ________.

Accepted Answer

The natural carbon dioxide produced by yeasts in a bottled wine is trapped inside, creating the bubbles that characterize champagne. Sweetness or dryness in wine is more a result of the amount of residual sugar left in the wine after fermentation, rather than the carbon dioxide production from yeasts. Brandy is a distilled beverage made from wine, where the carbon dioxide produced by yeasts is removed during the distillation process.

Question 20

Pulsed-field gel electrophoresis can be used to link a particular pathogen associated with disease outbreaks in a specific food source.

Accepted Answer

Pulsed-field gel electrophoresis is a type of molecular biology technique that can be used to determine the genetic relatedness of bacterial strains. When used in combination with epidemiological data, it can be a powerful tool for identifying the source of a disease outbreak associated with a particular food source.

Quiz 41: Microbiology of Food