Flashcards in Chapter 17: Fermentation: Desirable Effects of Microorganisms Deck (81)
What is Microbiology?
Is the study of living organisms too small to be seen by the unaided human eye
What are Microorganisms?
Organisms that are only visible through a microscope are called microorganisms
What do microorganisms do?
The multiply rapidly, and transfer easily from one surface to another (Cross-contamination)
What are some positive uses for Microorganisms?
Microorganisms that have a positive use in foods are bacteria, yeasts and molds
Bacteria are part of what Kingdom?
Bacteria are members of the Monera kingdom
Yeasts and molds are part of what Kingdom?
Yeasta and molds are members of the Fungi kingdom
Microorganisms depend on what to grow?
Microorganisms depend on outside sources of food to grow and multiply
What is Bacteria?
Bacteria are single-celled organisms that multiply through cell division
What is the Cytoplasm?
Bacteria cells have no nucleus and are filled with a gelatinous liquid called Cytoplasm
What are some characteristics of Bacteria?
1. Up to 3 micrometerslong
2. Classified by shape, cell wall structure, and oxygen needs
Bacteria have 3 basic shapes, what are they?
1. Bacilli: a rod shape
2. Cocci: have a spherical shape
3. Spirilla: have a spiral shape
Bacteria have 2 types of cell wall structures, how re they identified?
They are identified by the ability to be stained by a crystal violet dye, called Gram's stain
What are the 2 types of cell wall structures?
1. Gram-positive bacteria turn violet
2. Gram-negative bacteria turn red
Bacteria can be categorized by oxygen needs?
1. Aerobic: bacteria must have oxygen to function
2. Anaerobic bacteria function best in an oxygen-free environment
3. Facultative: bacteria can function in either type of environment
Aerobic bacteria does what to cabbage?
Aerobic bacteria spoil cabbage, but
-submerging cabbage in salt water does not allow aerobic bacteria to grow
- the anaerobic bacteria can multiply and develop the flavour and texture of sauerkraut
Bacterial growth rates depend on what?
Bacterial growth rates depend on pH, air, temperature and nutrients
What is Fungus?
A fungus is a plant that lacks chlorophyll
What are some characteristics of Fungi?
1. are not single-celled
2. Have a nucleus in their cells
3. Are widely distributed in nature and help organic matter decay
What are some examples of Fungi?
mushrooms, molds, mildew, rust, and yeast
How are Fungi classified?
Fungi are classified by their structure and reproduction methods
What are Hyphae?
Basic structures of most fungi is made up of filaments or tubes called hyphae
What are some characteristics of Hyphae?
1. Have elongated cells or chains of cells that absorb nutrients from the environment
2. Intertwine and form a branched network called a Mycelium
How does Mycelium reproduce?
Mycelium reproduces by creating spores, the reproductive cells of fungi
What are some characteristics of Spores?
1. Spores develop in a sac or balloon-like structure that explodes when full
2. Spores are microscopic and resistant to harsh environments
What are Molds?
Molds are fungi that form a mycelium structure with a fuzzy appearance
- many produce antibiotic that kill bacteria likely to be growing in the same area
What are Yeasts?
Yeasts are fungi with a single-celled structure that produce alcohol and carbon dioxide
- They form mycelium structures on soil or plants, but reproduce in animals by budding
What are some common Characteristics of Microorganisms?
1. Grow rapidly and are good sources of edible for animals
2. Can enhance or add to the nutritional value of food
3. Can enter a dormant or inactive state to protect themselves form a harsh environment
4. Reproduce when the environment supports growth needs
What is a Pure Culture?
A pure culture is a large volume of one type of microbe grown purposely
What are microorganisms used for at Food processing plants?
At food processing plants, large volumes of microorganisms are used in the development of such foods as pickles, cheese, and beverages