Question 1

Which of the following best describes the purpose of the 12D treatment in industrial food canning?

Accepted Answer

To reduce the population of endospores by 12 logarithmic cycles, resulting in only 1 survivor in $$10^{12}$$ endospores.

Question 2

Which microorganism is primarily responsible for the production of xanthan gum, and what is its industrial significance?

Accepted Answer

Xanthomonas campestris; used as a thickener in products like salad dressing and shampoo.

Question 3

A can of low-acid food swells and emits a sour odor. Which type of spoilage is most likely responsible, and what is the main cause?

Accepted Answer

Thermophilic anaerobic spoilage; caused by thermophilic bacteria that survive canning.

Question 4

Which of the following food preservation methods is most effective for sterilizing spices and why?

Accepted Answer

High-dose radiation (greater than 10 kGy); it can sterilize or greatly reduce bacterial populations.

Question 5

Which combination of microorganisms is used to produce yogurt?

Accepted Answer

Streptococcus thermophilus and Lactobacillus delbrueckii bulgaricus

Question 6

Which process is used to convert biomass into alternative energy sources, and what is a common product of this process in landfills?

Accepted Answer

Bioconversion; methane

Question 7

What is the main function of the Hazard Analysis and Critical Control Point (HACCP) system in food safety?

Accepted Answer

To identify points at which foods may become contaminated during processing.

Question 8

Which of the following statements about aseptic packaging is correct?

Accepted Answer

Paper and plastic are sterilized with hot hydrogen peroxide or UV light.

Question 9

Which microorganism is responsible for the aerobic conversion of ethanol to acetic acid in vinegar production?

Accepted Answer

Acetobacter

Question 10

A food scientist is designing a process to preserve a new fruit juice product. The juice is acidic and contains heat-resistant fungi. Which preservation method should be prioritized?

Accepted Answer

Processing at less than 100°C, but monitoring for Byssochlamys fulvus and Aspergillus.

Question 11

Which of the following best explains why prions are not affected by food irradiation?

Accepted Answer

Prions lack nucleic acids, making them resistant to ionizing radiation.

Question 12

Which of the following is a correct pairing of a fermented food and its primary fermenting microorganism?

Accepted Answer

Bread – Saccharomyces cerevisiae

Question 13

Which of the following best describes the role of the iChip in antibiotic discovery?

Accepted Answer

It allows researchers to grow bacteria in their natural environment, facilitating the discovery of new antibiotics.

Question 14

Which of the following is a real-world application of high-pressure food preservation (pascalization)?

Accepted Answer

Prewrapped, precooked foods are submerged in pressurized water tanks to kill pathogens while preserving color and flavor.

Question 15

Which of the following equations correctly represents the logarithmic reduction achieved by the 12D treatment in canning?

Accepted Answer

$$N = N_0$ 	imes 10$$^{-12}$$

Question 16

Which of the following best explains why gamma rays are used in food irradiation?

Accepted Answer

They have deep penetration, allowing them to sterilize food products thoroughly.

Question 17

Which of the following is a correct statement about the fermentation of beer and ale?

Accepted Answer

Malting converts starch-containing grains into carbohydrates that can be fermented by yeasts.

Question 18

Which of the following is a significant advantage of using algae for biofuel production?

Accepted Answer

Algae yield 20% of their weight in oil, and the remainder can be used to produce ethanol.

Question 19

Which of the following best describes the role of lactic acid bacteria in the production of sauerkraut?

Accepted Answer

They ferment sugars in cabbage, producing lactic acid that preserves the food.

Applied and Industrial Microbiology: Food Preservation, Fermentation, and Industrial Applications

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