Mizzou Food Science 1030 Exam 5 (Clarke)
Questions And Complete Answers
Microbiology - answer the study of the physiology, genetics, growth characteristics,
survival, and behavior of microbes.
Food Microbiologists focus on - answer microbes that grow and survive in food.
Microbes - answer responsible for most food borne illnesses
pathogens - answer cause disease and death
Beneficial microbes may control harmful ones and are used for many products such as -
answer yogurt, bread, beer, wine, and sausage.
Microorganisms are - answer living entities that are too small to be seen with the naked
eye.
-bacteria
-molds
-yeasts
Morphology - answer size and shape
Categories of Microorganisms - answer Bacteria
Fungi
-yeasts and molds
Protozoa (parasites)
viruses
Bacteria - answer unicellular prokaryotes found almost everywhere
Bacterial classifications - answer -Gram stain reaction: positive or negative
-Shape: coccus, bacillus, or spirillum
-Spore-forming ability: Yes or no
Fungi - answer Molds are unicellular or multicelled eukaryotes
,-growth is evidenced by mycellium.
Yeasts are unicellular eukaryotes
-most are spherical or oval and grow faster than molds
Protozoa - answer single celled eukaryotes
-classified by shape and size, locomotion, and life-cycle.
-Gardia, Cyclospora, Toxoplasma, and Entamoeba. Sources are intestinal tract and
water
Viruses - answer parasitic and are generally host-specific.
Most food viruses insert their RNA into the host's DNA for replication
Hepatitis and Norwals viruses are transmitted in foods
Most reproduction is by - answer cell division
Lag - answer no or slow growth, getting used to the environment.
Log - answer rapid growth
Stationary - answer as many cells are dying as being created
Death phase - answer waste products are toxic, food is gone.
Sources of Microorganisms - answer Air, water, and soils support microbes. They
contaminate everything.
The role of microbes - answer -Useful
-Spoilage
-Pathogenic
Intrinsic factors - answer refer to the food composition and characteristics that
influence microbial growth in the food.
Examples include:
Water activity
pH
Nutrients
Inhibitors such as preservatives
, Control of Microorganisms (FAT TOM) - answer -Food
-Acidity
-Temperature
-Time
-Oxygen
-Moisture
Nutrient Requirements vary with the type of organism. True or False? - answer True
The pH in which a microbe lives is a particular range defined by - answer minimum,
maximum, and optimum
-Optimum for most is near neutrality
The pH minimums are - answer -Bacteria: 4.5
-Yeasts: 3.0
-Molds: 2.0
Acid Foods - answer foods that have a natural pH of 4.6 or less
Acidified foods - answer are low acid foods to which acids are added
Low acid foods - answer foods with a pH greater than 4.6
Psychrophiles maximum temperature - answer 55 degrees Fahrenheit and love the cold.
Questions And Complete Answers
Microbiology - answer the study of the physiology, genetics, growth characteristics,
survival, and behavior of microbes.
Food Microbiologists focus on - answer microbes that grow and survive in food.
Microbes - answer responsible for most food borne illnesses
pathogens - answer cause disease and death
Beneficial microbes may control harmful ones and are used for many products such as -
answer yogurt, bread, beer, wine, and sausage.
Microorganisms are - answer living entities that are too small to be seen with the naked
eye.
-bacteria
-molds
-yeasts
Morphology - answer size and shape
Categories of Microorganisms - answer Bacteria
Fungi
-yeasts and molds
Protozoa (parasites)
viruses
Bacteria - answer unicellular prokaryotes found almost everywhere
Bacterial classifications - answer -Gram stain reaction: positive or negative
-Shape: coccus, bacillus, or spirillum
-Spore-forming ability: Yes or no
Fungi - answer Molds are unicellular or multicelled eukaryotes
,-growth is evidenced by mycellium.
Yeasts are unicellular eukaryotes
-most are spherical or oval and grow faster than molds
Protozoa - answer single celled eukaryotes
-classified by shape and size, locomotion, and life-cycle.
-Gardia, Cyclospora, Toxoplasma, and Entamoeba. Sources are intestinal tract and
water
Viruses - answer parasitic and are generally host-specific.
Most food viruses insert their RNA into the host's DNA for replication
Hepatitis and Norwals viruses are transmitted in foods
Most reproduction is by - answer cell division
Lag - answer no or slow growth, getting used to the environment.
Log - answer rapid growth
Stationary - answer as many cells are dying as being created
Death phase - answer waste products are toxic, food is gone.
Sources of Microorganisms - answer Air, water, and soils support microbes. They
contaminate everything.
The role of microbes - answer -Useful
-Spoilage
-Pathogenic
Intrinsic factors - answer refer to the food composition and characteristics that
influence microbial growth in the food.
Examples include:
Water activity
pH
Nutrients
Inhibitors such as preservatives
, Control of Microorganisms (FAT TOM) - answer -Food
-Acidity
-Temperature
-Time
-Oxygen
-Moisture
Nutrient Requirements vary with the type of organism. True or False? - answer True
The pH in which a microbe lives is a particular range defined by - answer minimum,
maximum, and optimum
-Optimum for most is near neutrality
The pH minimums are - answer -Bacteria: 4.5
-Yeasts: 3.0
-Molds: 2.0
Acid Foods - answer foods that have a natural pH of 4.6 or less
Acidified foods - answer are low acid foods to which acids are added
Low acid foods - answer foods with a pH greater than 4.6
Psychrophiles maximum temperature - answer 55 degrees Fahrenheit and love the cold.
