Principles of Food Science: Food Microbiology Flashcards

Comprehensive vocabulary flashcards based on the lecture notes for Principles of Food Science (ISH402), Chapter 4: Food Microbiology.

Microbiology

The study of microscopic organisms such as bacteria, yeast, fungi, algae, and viruses that are too small to be seen with the naked eye.

Food Microbiology

The study of microorganisms and their beneficial and harmful effects on the safety and quality of processed and raw foods.

Bacteria

Single-celled prokaryotes that possess a cell wall, cell membrane, and genetic material ($DNA$), such as Escherichia coli or Lactobacillus.

Fungi

Eukaryotic organisms with cell walls made of chitin, including molds, yeasts, and mushrooms.

Protozoa

Single-celled eukaryotes that do not have a cell wall and move using pseudopodia, cilia, or flagella.

Algae

Eukaryotic, mostly aquatic organisms containing chlorophyll used for photosynthesis.

Virus

Very small entities not made of cells that contain genetic material ($DNA$ or $RNA$) in a protein coat and only replicate inside host cells.

Yeast

Single-celled fungi that reproduce by budding and are used in fermentation processes.

Spoilage Bacteria

Bacteria that are usually not harmful but cause food to deteriorate, developing bad smells, tastes, or textures.

Beneficial Bacteria

Also known as "good bacteria," these are used in food production and fermentation, such as in yogurt and probiotics.

Pathogenic Bacteria

Harmful bacteria capable of causing foodborne illness, often without changing the color, odor, or feel of the food.

Lactic Acid Bacteria (LAB)

A group including Lactobacillus and Streptococcus that converts lactose into lactic acid, thickening milk to produce yogurt.

Probiotics

Beneficial bacteria that support digestive health and overall wellness, found in foods like kefir, miso, and kimchi.

Saccharomyces cerevisiae

A type of yeast that ferments sugar to produce carbon dioxide gas, causing dough to rise.

Intrinsic Factors

Chemical and physical characteristics inherent to the food itself, such as pH, nutrient content, and water activity.

Extrinsic Factors

Properties of the storage environment that affect microbial growth, such as temperature, relative humidity, and atmosphere.

Water Activity ($a_w$)

A measure of the amount of free or unbound water in food available for microbial growth.

Free Water

Water that can be easily obtained from foods via squeezing, cutting, or pressing, and can be utilized by microorganisms for growth.

Bound Water

Water that cannot be easily obtained from foods and cannot be utilized by microorganisms for growth.

Potentially Hazardous Food (PHF)

High-risk foods with high water activity ($a_w > 0.95$) and neutral pH that support rapid microbial growth.

Redox Potential ($Eh$)

A measure of the tendency of food components to accept or donate electrons, influencing oxygen availability for microbes.

Eugenol

A natural antimicrobial constituent found in cloves.

Allicin

A natural antimicrobial constituent found in garlic.

Lysozyme

An antimicrobial enzyme naturally occurring in eggs.

Psychrophiles

Microorganisms capable of growth at $0^{\text{o}}\text{C}$ with an optimum growth temperature below $20^{\text{o}}\text{C}$.

Mesophiles

Microorganisms that grow best in the temperature range of $30^{\text{o}}\text{C}$ to $40^{\text{o}}\text{C}$, including common foodborne pathogens.

Thermophiles

Heat-loving bacteria that grow at $45^{\text{o}}\text{C}$ and above, with an optimum range of $55^{\text{o}}\text{C}$ to $65^{\text{o}}\text{C}$.

Relative Humidity (RH)

Environmental factor that affects food water activity; high levels can increase surface moisture and encourage mold growth.

Aerobes

Microorganisms that cannot grow without oxygen, such as Mycobacterium tuberculosis.

Anaerobes

Microorganisms that only grow in the absence of free oxygen, such as Clostridium.

Facultative Anaerobes

Microorganisms that can grow under both aerobic and anaerobic conditions, such as most Enterobacteriaceae.

Food Spoilage

The process in which food deteriorates to the point it is no longer edible, indicated by changes in appearance, smell, texture, or taste.

Enzymes

Biological catalysts, mainly proteins, that speed up chemical reactions causing changes in food ripening, texture, and color.

Pathogen

A microbe that causes illness, either by infecting body cells or by releasing toxins.

Waterborne Disease

Illness caused by recreational or drinking water contaminated by disease-causing microbes like Typhoid fever or Hepatitis A.

Traceback

The process of identifying a common point of contamination in the distribution chain from farm to fork by reviewing records.