11. Controlling Microbial Growth

What are some advantages and disadvantages of using ionizing radiation to sterilize food?

Which of the following types of radiation is more widely used as an antimicrobial technique?

a. Electron beams

b. Visible light waves

c. Radio waves

d. Microwaves

The preservation of beef jerky from microbial growth relies on which method of microbial control?

a. Filtration

b. Lyophilization

c. Desiccation

d. Radiation

Lyophilization can be described as:

a. Freeze-drying

b. Deep-freezing

c. Refrigeration

d. Pickling

How does irradiation control microbial growth?

Which of the following items functions most like an autoclave?

a. Boiling pan

b. Incinerator

c. Microwave oven

d. Pressure cooker

Lyophilization in food preservation is by ________.

a. Cell lysis

b. Gamma radiation

c. Rapid heating

d. Freeze-drying

The endospores of which organism can be used as a biological indicator of sterilization?

a. Bacillus stearothermophilus

b. Salmonella enterica

c. Mycobacterium tuberculosis

d. Staphylococcus aureus

A sample of E. coli has been subjected to heat for a specified time, and 90% of the cells have been destroyed. Which of the following terms best describes this event?

a. Thermal death point

b. Thermal death time

c. Decimal reduction time

d. None of the above

How does high pressure processing (HPP) control microbial populations?

In practical terms in everyday use, which of the following statements provides the definition of sterilization?

a. Sterilization eliminates all organisms and viruses

b. Sterilization eliminates harmful microorganisms and viruses

c. Sterilization eliminates prions

d. Sterilization eliminates hyperthermophiles

Defend the following statement: “Pasteurization is not sterilization.”

Which of the following is most likely to be bactericidal?

a. Membrane filtration

b. Ionizing radiation

c. Lyophilization (freeze-drying)

d. Deep-freezing

e. All of the above

Which of the following pathogens would hyperbaric oxygen therapy, a treatment that increases the level of dissolved oxygen in tissues, most likely ward off? Select all that apply.

a. Anaerobic thermophile

b. Anaerobic mesophile

c. Facultative anaerobic thermophile

d. Facultative anaerobic mesophile

e. Microaerophilic mesophile

Foods packed in plastic for microwaving are

a. Dehydrated.

b. Freeze-dried.

c. Packaged aseptically.

d. Commercially sterilized.

e. Autoclaved.