Food Safety and Thermal Processing Exam Review

A collection of flashcards based on key concepts from food safety and thermal processing.

The pH of a low-acid food is less than 4.6.

FALSE: It should be a HIGH acid food with a lower pH.

Clostridium botulinum is the target organism for pasteurization of low-acid milk.

FALSE: C. botulinum is not the target organism for milk or pasteurization processes.

The area under the curve plotted with time on the x-axis and temperature on the y-axis yields the F value of a process.

FALSE: It should be time on the y-axis and temperature on the x.

An important reason for refrigerating low-acid canned food after opening is to prevent botulism.

FALSE: It is to prevent contamination by different bacteria; botulism should not be present after canning.

Lethal rate has units of time.

FALSE: It does not have units and measures the relative effect of temperature on microbial kill.

In canning and retorting, thermophilic spores are generally not destroyed.

TRUE: Thermophilic microorganisms can withstand high temperatures.

In a hot fill process, the inside of the container is free of pathogens at the time of filling.

FALSE: It is the hot product that inactivates microorganisms.

Ultra-pasteurized products (such as milk) do not need refrigeration.

FALSE: They are not shelf-stable.

For a first-order reaction, the concentration of the reacting species decreases linearly with time.

FALSE: This describes a zero-order reaction; a first-order reaction is linear with ln(c).

High decimal reduction times (D values) are associated with thermally resistant organisms.

TRUE.

The units of F value and C value are the same.

TRUE: Both have units of time.

In a thermal process, lethal rate decreases as temperature decreases.

TRUE.

The target organism for a low-acid product is the same for retorting and aseptic processing.

TRUE.

A scraped surface heat exchanger is effective for heating viscous food products.

TRUE.

An advantage of steam infusion is it does not require a vacuum chamber.

FALSE: Steam infusion dilutes the product so a vacuum is still needed.

What is Decimal Reduction Time (D)?

D is the time required for a 1-log reduction of the target microorganism at a specific temperature; units are in time.