Food Microbiology Exam 1

What are the 3 roles of microorganisms in food?

Fermentation, spoilage, and foodborne diseases

True or false: Spoiled foods contain a high number of microorganisms and will cause food poisoning if consumed

False

What is the major source of microorganisms found in fruits and vegetables?

Soil

Which genus of bacteria is most frequently found in spoiled vegetables and fruits?

Pseudomonas

True or False: A walnut is an example of a highly perishable food

False

Which microbe, according to the CDC, is often associated with poultry but not typically with fresh red meats?

Campylobacter

Define food spoilage

Any change in appearance, smell, or taste of a food product that makes it unacceptable to the consumer

What are some examples of highly perishable foods?

Meats, fish, poultry, eggs, milk, most fruit & veg

What are some examples of semi-perishable foods?

Potatoes, some apples, nuts

What are some examples of non-perishable foods?

Sugar, flour, rice, dry beans

Where can foods acquire microorganisms?

From raw ingredients, or contaminated during processing, storage, and serving

Where are microorganisms obtained in raw ingredients?

Indigenous microbes, animal feeds, water, soil

How is food contaminated during processing, storage, and serving?

Utensils/equipment, food handlers, air, or dust

What are the two types of methods for microbial testing?

Counting (microbial loads) and detecting (presence/absence of pathogens)

When considering a test sample, how does sensitivity correlate with sample size?

Sensitivity increases as sample size increases

What is the standard CFU range for countable plates?

25-250 CFU’s

What is the most probable number (MPN) enumeration method?

Statistical estimation of the # of cells in a sample