Food Microbiology Study Notes

Definition: Microorganisms that cause illness when consumed with food.
Types of Pathogens:
- Bacteria:
  - Salmonella: Common in poultry, eggs; causes gastroenteritis.
  - Escherichia coli (E. coli): Found in undercooked beef; can cause severe illness.
  - Listeria monocytogenes: Found in deli meats and dairy; can be severe for pregnant women.
- Viruses:
  - Norovirus: Highly contagious; often linked to contaminated water and shellfish.
  - Hepatitis A: Can spread through contaminated food, particularly shellfish.
- Parasites:
  - Giardia: Can be found in contaminated water and produce.
  - Toxoplasma: Often associated with undercooked meat.
Transmission: Through contaminated food or water, improper cooking, and cross-contamination.
Prevention:
- Proper cooking temperatures.
- Good hygiene practices.
- Safe food storage methods.

Definition: Metabolic process where microorganisms convert sugars to acids, gases, or alcohol under anaerobic conditions.
Types of Fermentation:
- Lactic Acid Fermentation:
  - Performed by lactic acid bacteria (LAB).
  - Produces yogurt, sauerkraut, and pickles.
- Ethanol Fermentation:
  - Carried out by yeast (e.g., Saccharomyces cerevisiae).
  - Used in beer and bread production.
- Acetic Acid Fermentation:
  - Converting ethanol to acetic acid using acetic acid bacteria.
  - Important in vinegar production.
Benefits:
- Preservation of food by lowering pH.
- Enhancement of flavor and texture.
- Probiotic effects promoting gut health.

Definition: Deterioration of food quality caused by microorganisms.
Types of Spoilage:
- Bacterial Spoilage:
  - Leads to putrefaction; produces foul odors.
  - Common in meat and dairy products.
- Fungal Spoilage:
  - Molds produce mycotoxins; visible as fuzzy growth.
  - Commonly found in bread and fruits.
Factors Influencing Spoilage:
- Temperature: Higher temperatures promote microbial growth.
- Moisture: High moisture levels facilitate spoilage.
- pH Levels: Low pH can inhibit some spoilage organisms.
Prevention:
- Proper refrigeration and freezing.
- Use of preservative agents (salt, sugar, vinegar).
- Regular inspection and removal of spoiled food.

Microorganisms that can induce illness when ingested through food.
Bacteria:
- Salmonella: Found primarily in poultry and eggs; responsible for gastroenteritis.
- Escherichia coli (E.coli): Present in undercooked beef; can lead to severe health complications.
- Listeria monocytogenes: Common in deli meats and dairy products; poses significant risks for pregnant women.
Viruses:
- Norovirus: Highly infectious; often associated with contaminated water and shellfish.
- Hepatitis A: Transmitted via contaminated food, especially shellfish.
Parasites:
- Giardia: Found in contaminated water, effects produce as well.
- Toxoplasma: Linked to consumption of undercooked meat.
Modes of transmission include ingestion of contaminated food or water, insufficient cooking, and cross-contamination.
Prevention strategies encompass proper cooking temperatures, hygiene practices, and safe food storage techniques.

Metabolic process where microorganisms convert sugars into acids, gases, or alcohol in the absence of oxygen.
Types of Fermentation:
- Lactic Acid Fermentation: Conducted by lactic acid bacteria (LAB) leading to the production of yogurt, sauerkraut, and pickles.
- Ethanol Fermentation: Executed by yeasts like Saccharomyces cerevisiae, crucial for beer and bread making.
- Acetic Acid Fermentation: Involves converting ethanol into acetic acid through acetic acid bacteria, essential for vinegar production.
Benefits of Fermentation include food preservation through pH reduction, flavor and texture enhancement, and probiotic effects for improved gut health.

Deterioration of food quality driven by microorganisms.
Types of Spoilage:
- Bacterial Spoilage: Results in putrefaction while generating unpleasant odors; predominantly seen in meat and dairy products.
- Fungal Spoilage: Molds can create harmful mycotoxins and are visually identified by fuzzy growths, primarily affecting bread and fruits.
Factors influencing spoilage include:
- Temperature: Elevated temperatures encourage microbial growth.
- Moisture: High moisture levels accelerate spoilage processes.
- pH Levels: Lower pH can inhibit specific spoilage organisms.
Preventative measures include proper refrigeration and freezing, usage of preservative agents like salt, sugar, and vinegar, and regular checks for and removal of spoiled food.

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