Microbiology: Growth and Reproduction of Microorganisms

These vocabulary flashcards cover the fundamental concepts of microbial growth, reproduction, and the FAT TOM factors as discussed in the microbiology lecture.

Microbial Growth

An increase in the number of microbial cells rather than an increase in cell size.

Binary Fission

A process of reproduction where one cell divides into two identical daughter cells.

FAT TOM

An acronym representing six key factors affecting microbial growth: Food, Acidity, Time, Temperature, Oxygen, and Moisture.

Salmonella

Bacteria often found on the shells and inside of eggs, and in protein-rich foods like meat.

Clostridium perfringens

A bacterium commonly found in meat, poultry, and gravies cooked in large batches and held at unsafe temperatures.

Bacillus cereus

The main causative agent of "fried rice syndrome," occurring when boiled rice is left at room temperature.

Geotrichum candidum

An organism that causes "dairy mold" on butter and cream.

Yarrowia lipolytica

An ascomycetous yeast found in the environment and meat products, especially sausages and cheese.

Penicillium roqueforti

A mold that can grow on butter and soft cheeses, causing blue-green mold.

Lactobacillus delbrueckii subsp. bulgaricus

A bacteria used in yogurt production that ferments lactose into lactic acid.

Saccharomyces cerevisiae

Commonly known as baker's yeast, it metabolizes glucose to produce carbon dioxide during bread making.

Aspergillus oryzae

A mold used in soy sauce production that secretes enzymes to break down starches into simpler sugars.

Propionibacterium freudenreichii

A Gram-positive, nonmotile bacterium in Swiss cheese that converts lactic acid into propionic acid and carbon dioxide, creating the "eyes" or holes.

Bacillus subtilis and Bacillus licheniformis

Salt-tolerant bacteria that produce proteolytic enzymes in shrimp paste to enhance umami taste.

Acidophiles

Microorganisms that grow best in acidic environments with low pH levels.

Neutrophiles

Microorganisms that grow best in neutral environments, typically around pH $7$.

Alkaliphiles

Microorganisms that grow best in basic or alkaline environments with high pH levels.

Lactic Acid Bacteria (LAB)

Beneficial microorganisms, such as Lactobacillus acidophilus, that produce lactic acid to lower pH and inhibit pathogens.

Nisin

An odorless, colorless, tasteless antimicrobial peptide secreted by LAB that disrupts pathogen cell walls.

Lag Phase

The first phase of the bacterial growth curve characterized by adaptation and slow growth.

Log Phase

The phase of exponential multiplication in the bacterial growth curve.

Stationary Phase

The phase where nutrient depletion and waste accumulation cause growth to slow and spores to form.

Death Phase

The final growth phase where bacteria decline due to the accumulation of toxic byproducts.

Danger Zone

The temperature range between $5^\text{o}\text{C}$ and $60^\text{o}\text{C}$ ($41^\text{o}\text{F}$ to $135^\text{o}\text{F}$) where bacteria grow rapidly.

Psychrophiles

Microbes that are found in refrigerated foods.

Mesophiles

Microbes that thrive at moderate temperatures, including human pathogens like Salmonella.

Thermophiles

Heat-loving microbes.

Listeria monocytogenes

A bacterium capable of growing at refrigeration temperatures, dangerous for pregnant women and newborns.

Escherichia coli O157:H7

A pathogenic strain that leads to severe foodborne illness, characterized by bloody diarrhea and stomach cramps.

Taenia saginata

The beef tapeworm, which may cause mild gastrointestinal upset.

Toxoplasma gondii

A protozoan parasite present in undercooked meat that can cause toxoplasmosis.

Obligate Aerobes

Microorganisms that require oxygen and cannot survive without it.

Facultative Aerobes

Microorganisms that use oxygen but can survive without it.

Aerotolerant Anaerobes

Microorganisms that do not use oxygen but can grow in its presence.

Obligate Anaerobes

Microorganisms that are unable to use oxygen and cannot survive if it is present.

Microaerophiles

Microorganisms that use oxygen but only at very low concentrations.

Water Activity ($Aw$)

A measurement of the energy status of the "free" water in a system available for microbial growth.

Staphylococcus aureus

A foodborne pathogen with a low water activity tolerance of $0.86$.