DiseaseCausing Microorganisms and the Conditions They Need to Grow

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Disease-Causing Microorganisms and the Conditions
They Need to Grow Barriers for Controlling the
Growth of Microorganisms
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Microorganism Small living organism Pathogen
A disease-causing microorganism Toxin
Poison Spoilage Microorganism Microorganism
that causesspoilage, but not illness
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Microorganisms That Can ContaminateFood and
Cause Foodborne Illness
Bacteria Viruses Parasites Fungi
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• Living, single-celled
• Carried by food, water, humans and insects
• Can reproduce rapidly
• Some survive freezing
• Some form spores
• Some spoil food others cause disease
• Some cause illness by producing toxins

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Growth Stages of Bacteria
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Bacterial Growth
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What Microorganisms Need to Grow
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• Food Microorganisms require nutrients to grow
• Proteins
• Carbohydrates

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Acidity Pathogenic bacteria grow well at a pH
of 4.6 to 7.5
Raw Chicken 5.56.4
Butter 6.06.8
Egg Yolks 6.06.3
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Temperature The Temperature Danger Zone(TDZ)
41ºF to 140ºF (5ºC to 60ºC)

• Most microorganisms grow well in the TDZ
• Some survive and grow outside the TDZ

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Time Pathogenic microorganisms can grow to high
levels if they remain in the TDZ for more than
four hours
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• Oxygen Microorganisms have differentoxygen
  needs for growth
• Aerobic needs oxygen to grow
• Anaerobic grows only when oxygen is absent
• Facultative can grow with or without oxygen

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Moisture Most potentially hazardous foods have
a water activity of .85 or above
Raw Chicken and Butter Water Activities of
.951.0
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Barriers That Control the Growthof Microorganisms
Make the foodmore acidic
Raise or lowerthe temperature of the food
Lessen the time in the TDZ
Lower the water activity
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Major Foodborne Illnesses Caused by Bacteria

• Bacillus cereus gastroenteritis
• Botulism
• Campylobacteriosis
• E. coli O157H7 EHEC
• Vibrio gastroenteritis
• Yersiniosis

• Salmonellosis
• Shigellosis
• Listeriosis
• Staphyloccocal food poisoning
• Clostridium perfringens Enteritis

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SalmonellosisType of Illness Infection,
possibly toxin-mediated
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ListeriosisType of Illness Infection
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Staphylococcal Food PoisoningType of Illness
Intoxication
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Clostridium perfringensType of Illness
Toxin-mediated infection
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BotulismType of Illness Intoxication
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E. coli O157H7 EHECType of Illness
Toxin-mediated infection
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• Cant reproduce outside a living cell
• Do not require a PHF to be transmitted
• Usually contaminate food through poor
  personal hygiene
• May survive freezing and cooking
• Contaminate food and water

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Major Foodborne Illnesses Caused by Viruses

• Hepatitis A
• Norwalk Virus Gastroenteritis
• Rotavirus Gastroenteritis

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Hepatitis AType of Illness Infection
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Norwalk Virus GastroenteritisType of Illness
Infection
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Parasites Need to live in or on a host organism
in order to survive
Host Person Animal
Plant
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Keys to Prevention

• Freeze properly
• Cook to proper temperatures
• Avoid cross-contamination
• Use sanitary water supplies
• Wash hands properly

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Major Foodborne Illnesses Caused by Parasites

• Trichinosis
• Anisakiasis
• Giardiasis
• Toxoplasmosis
• Intestinal Cryptosporidiosis
• Cyclosporiasis

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TrichinosisType of Illness Infection
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AnisakiasisType of Illness Infection
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Fungi Commonly cause food spoilage, not illness
Fungi Molds Yeasts
Mushrooms
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Foodborne Infections Result when pathogens grow
in intestines after a person eats food
contaminated by them Foodborne Intoxications
Result from eating food containing poisonous
toxins Foodborne Toxin-Mediated Infections
Result from toxins produced by pathogens
growing in the intestines
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Prepare an outline for a discussion of the four
types of microorganisms. Include examples of what
microorganisms need to survive and grow.
Highlight the conditions managers have the most
influence over.
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• Challenge participants to create a list of foods
  high in acid and another list of highly
  alkaline foods. Reward the participant who
  comes up with the most examples and have him
  or her share the list with the class.
• Create a blank handout of a thermometer and
  have participants indicate the space for the
  temperature danger zone.