Microbiology of Bacteria

Questions and Answers

Perform fermentation of vegetable, meat, and milk

Heat and chemical resistant (correct)

Psychotropic bacteria

Fastidious (require vitamin B)

Listeria

Propionibacterium

Lactobacillus

Brochothrix (correct)

It is a pathogenic bacterium

It can grow at temperatures below 40°C (correct)

It is commonly found in the human gut

It is a psychotropic bacterium

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Study Notes

Aerobic Organisms
- Listeria monocytogenes
  - Psychotropic and facultative anaerobic.
  - Pathogenic, problematic in food industries.
  - Can survive up to 20% NaCl, exhibiting preservative resistance.
- Brochothrix
  - Associated with spoilage of red meat.
  - Lipolytic, also psychotropic.
- Lactobacillus
  - Fastidious, requiring vitamin B.
  - Performs fermentation in vegetables (Lactobacillus plantarum), meat, and milk as lactic acid bacteria.
  - Probiotic strains provide health benefits.
Anaerobic Organism
- Propionibacterium
  - Heterofermentative, ferments glucose or lactic acid into propionic acid and CO2 in cheese, creating gas bubbles.
  - Found on human skin, some species used as starter cultures in dairy.

Gram-Positive, Endospore Forming Rods
- Aerobic Organisms
  - Bacillus
    - Spoilage microorganisms found in soil and gut of humans and animals.
    - Notable for heat and chemical resistance.
    - Growth ceases below 43 °C; canned foods (e.g., Bacillus stearothermophilus) should be stored under 40 °C, especially low-acid foods (pH > 4.5).
    - Bacillus cereus and Bacillus subtilis are pathogenic; other species typically non-pathogenic.
- Anaerobic Organism
  - Clostridium
    - Recognized as pathogenic microorganisms involved in various infections.