All Of The Following Are Routinely Used To Preserve Food Except

5. Which concentration of ethyl alcohol is the most effective germicide?

6. Which of the following chemical agents can most reliably be used to sterilize objects?

A. Alcohol B. Phenolic compounds

C. Ethylene oxide gas D. Formaldehyde

7. All of the following are routinely used to preserve foods, except

A. high concentrations of sugar.

B. high concentrations of salt.

C. benzoic acid.

D. freezing.

E. ethylene oxide.

8. Aseptically boxed juices and cream containers are processed using which of the following heating methods?

A. Canning

B. High-temperature-short-time (HIST) method

C. Low-temperature-long-time (LTLT) method

D. Ultra-high-temperature (UHT) method

9. Commercial canning processes are designed to ensure destruction of which of the following?

A. All vegetative bacteria

B. All vegetative bacteria and their endospores

C. Endospores of Clostridium botulinum

E. Mycobacterium tuberculosis

10. Which of the following is false?

A. A chemical that is a high-level disinfectant cannot be used as a sterilant.

B. Heat-sensitive critical items must be treated with a sterilant.

C. Low numbers of endospores may remain on semicritical items.

D. Standard sterilization procedures do not destroy prions.

E. Quaternary ammonium compounds can be used to disinfect food preparation surfaces.

128 Chapter 5 Control of Microbial Growth Applications

1. An agriculture extension agent is preparing pamphlets on preventing the spread of disease in the household. In the pamphlet, he must explain the appropriate situations for using disinfectants around the house. What situations should the agent discuss?

2. As a microbiologist representing a food corporation, you have been asked to serve on a health food panel to debate the need for chemical preservatives in foods. Your role is to prepare a statement that compares the benefits of chemical preservatives and the risks. What points must you bring up that indicate the benefits of chemical preservatives?

Critical Thinking

1. This graph shows the time it takes to kill populations of the same microorganism under different conditions. What conditions would explain the differences in lines a, b, and c

Time

2. This diagram shows the filter paper method used to evaluate the inhibitory effect of chemical agents, heavy metals, and antibiotics on bacterial growth. A culture of test bacteria is spread uniformly over the surface of an agar plate. Small filter paper discs containing the material to be tested are then placed on the surface of the medium. A disc that has been soaked in sterile distilled water is sometimes added as a control. After incubation, a film of growth will cover the plate, but a clear zone will surround those discs that contain an inhibitory compound. The size of the zone reflects several factors, one of which is the effectiveness of the inhibitory agent. What are two other factors that might affect the size of the zone of inhibition? What is the purpose of the control disc? If a clear area were apparent around the control disc, how would you interpret the observation?

Control disc

Clear area' around disc

Control disc

Clear area' around disc

Filter paper discs soaked in material to be tested (A-E)

Bacterial growth on agar surface

Filter paper discs soaked in material to be tested (A-E)

Bacterial growth on agar surface

Time

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Responses

  • Jasmine
    Which of the following substances is used to preserve foods?
    2 years ago

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