Microbial Growth Factors Quiz

What is the optimal pH range for most microorganisms?

• 8.0-9.0

• 7.0-8.0

• 6.0-7.0

• 4.0-5.0

Which microorganism can grow at a pH as low as 4.4?

• Vibrio parahaemolyticus

• Bacillus cereus

• Escherichia coli

• Clostridium botulinum

What is the water activity (Aw) of fresh meat and fish?

• .95

• .80

• .99

• .85

Which of the following foods has the lowest water activity?

• Fresh meat

• Dried fruit

• Bread

• Cheese spread

What does a positive Eh value indicate?

• Reduced food

• Oxidized food

• Neutral food

• Spoiled food

Which microorganism is classified as a thermophile?

• Enterococcus

• Bacillus

• Clostridium botulinum

• Pseudomonas

What is the role of antimicrobial constituents in food?

• Change color

• Increase moisture

• Prevent spoilage

• Enhance flavor

Which of the following is an example of an intrinsic factor?

• Presence of gases

• Nutrient content

• Temperature of storage

• Relative humidity

What is the effect of high relative humidity on food with low Aw?

• Decreases spoilage

• Enhances flavor

• Increases spoilage

• No effect

Which gas is used to control microorganisms in foods?

• Oxygen

• Hydrogen

• Nitrogen

• Carbon Dioxide