1. 2• The Microworld
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2. 2• The Microworld
Microorganism Small, living organism Pathogen Disease-causing microorganism Toxin Poison Spoilage Microorganism Microorganism that causes spoilage, but not illness
Talking Points:
Define the key terms for participants.
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3. Microorganisms That Can Contaminate Food And Cause Foodborne Illness
2• The Microworld
Microorganisms That Can Contaminate Food And Cause Foodborne Illness
Bacteria Viruses Parasites Fungi
Talking Points:
Discuss the four types of microorganisms that can contaminate food: bacteria, viruses, parasites, and fungi.
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4. Basic Characteristics
2• The Microworld
Basic Characteristics
Living, single-celled
Can be carried by food, water, humans, and insects
Can reproduce rapidly under favorable conditions
Talking Points:
Tell participants that knowing what bacteria are and understanding how they grow is the first step in controlling them.
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5. Basic Characteristics (continued)
2• The Microworld
Basic Characteristics (continued)
Some survive freezing
Some form spores
Some spoil food; others cause illness
Some produce toxins that cause illness
Talking Points:
Tell participants that knowing what bacteria are and understanding how they grow is the first step in controlling them.
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2-5

6. Growth Stages Of Bacteria
2• The Microworld
Growth Stages Of Bacteria
Talking Points:
Review the four phases (stages) of bacterial growth.
Lag phase: The adjustment phase for bacteria where their numbers are stable and they are preparing for growth.
Log phase: The growth phase for bacteria. Here they grow remarkably fast, doubling their numbers as often as every twenty minutes.
Stationary phase: The phase reached when the number of bacteria growing equals the number dying.
Death phase: The phase reached when the number of bacteria dying exceeds the number growing. Here the population declines.
Point out that to control the growth of bacteria, it is important to prolong the lag phase as long as possible. This can be accomplished by controlling bacteria’s requirements for growth: food, acidity, time, temperature, oxygen, and moisture.
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7. Bacterial Growth 2• The Microworld Talking Points:
Explain that bacteria reproduce by splitting in two.
Use the slide illustration to show how rapidly bacteria can reproduce. Point out that as long as conditions are favorable, bacteria can grow and multiply very rapidly—doubling their numbers as often as every twenty minutes.
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8. What Microorganisms Need To Grow
2• The Microworld
What Microorganisms Need To Grow
Talking Points:
Explain how the acronym FAT TOM can be used to remember the conditions necessary for the growth of foodborne microorganisms. Discuss each condition thoroughly as you view the next six slides.
Ask participants to identify the easiest conditions to control in a restaurant or foodservice setting. (Time and temperature)
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9. 2• The Microworld
Food Microorganisms require nutrients found in potentially hazardous food to grow
Proteins
Carbohydrates
Talking Points:
Explain that microorganisms need nutrients such as proteins and carbohydrates to grow. These nutrients typically are found in potentially hazardous food such as meat, poultry, dairy products, and eggs.
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2-9

10. 2• The Microworld
Acidity Microorganisms grow well in food with a slightly acidic to neutral pH (4.6 to 7.5)
Talking Points:
Explain that pH is a measure of the amount of acid in a food.
Point out that the pH scale ranges from 0 to 14. Food with a pH between 0 and 7 is acidic, while food with a pH between 7 and 14 is alkaline. A pH of 7 is neutral.
Explain that microorganisms grow best in food that is slightly acidic to neutral. Point out the pH of the raw chicken and the egg yolks.
Explain that potentially hazardous food typically has a pH between
Raw Chicken pH =
Egg Yolks pH =
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11. Temperature TDZ = 41˚F to 140˚F (5˚C to 60˚C)
2• The Microworld
Temperature TDZ = 41˚F to 140˚F (5˚C to 60˚C)
Most microorganisms grow well in the TDZ
Some survive and grow outside the TDZ
Talking Points:
Explain that foodborne microorganisms grow best at temperatures between 41°F and 140°F (5°C and 60°C). This range is known as the temperature danger zone (TDZ).
Explain that cooking food to the required minimum internal temperatures can kill microorganisms, while refrigerating it can slow their growth.
Point out that some foodborne microorganisms grow well at refrigeration temperatures and some form spores, that can survive extreme heat and cold. Therefore, it is important to handle food carefully when it is thawed, cooked, cooled, and reheated, since it is exposed to the TDZ during these times.
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2-11

12. 2• The Microworld
Time Foodborne microorganisms can grow to harmful levels if they remain in the TDZ for more than four hours
Talking Points:
Explain that foodborne microorganisms need sufficient time to grow even under favorable conditions.
Explain that bacteria can grow to levels high enough to cause illness if food is left in the TDZ for four hours or longer. Refer back to slide 2-7.
Stress the importance of controlling the amount of time potentially hazardous food remains in the TDZ.
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13. 2• The Microworld
Oxygen Different foodborne microorganisms have different oxygen requirements
Some need oxygen to grow (aerobic)
Some grow only when oxygen is absent (anaerobic)
Most grow with or without oxygen (facultative)
Talking Points:
Emphasize that most microorganisms that cause foodborne illness can grow with or without oxygen.
Explain that packaging can be used to control the growth of foodborne microorganisms. For example, vacuum packaging can be used to control the growth of aerobic microorganisms that might be present.
Explain that thick food offers optimal conditions for the growth of anaerobic microorganisms.
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14. 2• The Microworld
Moisture Most potentially hazardous food has a water activity (aw) of .85 or higher
Talking Points:
Explain that the amount of moisture available in a food for microorganisms to grow is called its water activity (aw).
Explain that water activity is measured on a scale of 0 through 1.0, with water having a water activity of 1.0.
Point out that most foodborne microorganisms grow best in food with a water activity between .85 and .97.
Raw chicken aw =
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2-14

15. Barriers For Controlling The Growth Of Microorganisms
2• The Microworld
Barriers For Controlling The Growth Of Microorganisms
Raise or lower the temperature of food
Make food more acidic
Talking Points:
Discuss each barrier for controlling the growth of microorganisms. Challenge participants to give examples of how they could be applied. Possible answers include:
Make food more acidic. Add vinegar, lemon juice, lactic acid, or citric acid to the food.
Raise or lower food temperature. Cook food to the proper temperature, refrigerate it to 41°F (5°C) or lower, or freeze it.
Lower the food’s water activity. Dry food by adding sugar, salt, alcohol, or acid. Air-dry or freeze-dry food to remove water.
Minimize time food spends in the TDZ. Prepare food in small batches, as close to service as possible.
Stress the importance of using multiple barriers.
Lower the food’s water activity
Minimize time food spends in the TDZ
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16. Caused By Bacteria Salmonellosis Shigellosis Listeriosis
2• The Microworld
Caused By Bacteria
Salmonellosis
Shigellosis
Listeriosis
Staphylococcal Gastroenteritis
Clostridium perfringens Gastroenteritis
Bacillus cereus Gastroenteritis
Botulism
Campylobacteriosis
Hemorrhagic colitis
Vibrio spp. Gastroenteritis
Yersiniosis
Talking Points:
Introduce the major foodborne illnesses caused by bacteria.
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17. 2• The Microworld
Illness: Salmonellosis Bacteria: Salmonella spp. Type of Illness: Infection, possibly toxin-mediated
Talking Points:
Discuss the following:
Bacteria associated with the illness
Type of illness
Symptoms of the illness
Sources of the illness
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18. 2• The Microworld
Illness: Salmonellosis (continued) Bacteria: Salmonella spp. Type of Illness: Infection, possibly toxin-mediated
Talking Points:
Discuss the following:
Food involved in outbreaks
Prevention measures
Remind participants that some shell eggs are treated to eliminate Salmonella spp.
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19. 2• The Microworld
Illness: Listeriosis Bacteria: Listeria monocytogenes Type of Illness: Infection
Talking Points:
Discuss the following:
Bacteria associated with the illness
Type of illness
Symptoms of the illness
Sources of the illness
Tell participants that listeriosis typically affects the very young and the elderly.
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20. 2• The Microworld
Illness: Listeriosis (continued) Bacteria: Listeria monocytogenes Type of Illness: Infection
Talking Points:
Discuss the following:
Food involved in outbreaks
Prevention measures
Point out the importance of cooking food to the proper internal temperature and avoiding cross-contamination.
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21. 2• The Microworld
Illness: Staphylococcal Gastroenteritis Bacteria: Staphylococcus aureus Type of Illness: Intoxication
Talking Points:
Discuss the following:
Bacteria associated with the illness
Type of illness
Symptoms of the illness
Sources of the illness
Stress that foodhandler’s skin and nose are the most common sources of this microorganism.
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22. 2• The Microworld
Illness: Staphylococcal Gastroenteritis (continued) Bacteria: Staphylococcus aureus Type of Illness: Intoxication
Talking Points:
Discuss the following:
Food involved in outbreaks
Prevention measures
Stress that good personal hygiene is vital to preventing the illness.
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23. 2• The Microworld
Illness: Clostridium perfringens Gastroenteritis Bacteria: Clostridium perfringens Type of Illness: Toxin-mediated infection
Talking Points:
Discuss the following:
Bacteria associated with the illness
Type of illness
Symptoms of the illness
Sources of the illness
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24. 2• The Microworld
Illness: Clostridium perfringens Gastroenteritis (continued) Bacteria: Clostridium perfringens Type of Illness: Toxin-mediated infection
Talking Points:
Discuss the following:
Food involved in outbreaks
Prevention measures
Remind participants that careful time and temperature control when cooling and reheating food is essential to preventing the growth of Clostridium perfringens.
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25. 2• The Microworld
Illness: Botulism Bacteria: Clostridium botulinum Type of Illness: Intoxication
Talking Points:
Discuss the following:
Bacteria associated with the illness
Type of illness
Symptoms of the illness
Sources of the illness
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26. 2• The Microworld
Illness: Botulism (continued) Bacteria: Clostridium botulinum Type of Illness: Intoxication
Talking Points:
Discuss the following:
Food involved in outbreaks
Prevention measures
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27. 2• The Microworld
Illness: Hemorrhagic colitis Bacteria: Shiga toxin-producing Escherichia coli, including O157:H7 and O157:NM Type of Illness: Toxin-mediated infection
Talking Points:
Discuss the following:
Bacteria associated with the illness
Type of illness
Symptoms of the illness
Sources of the illness
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28. 2• The Microworld
Illness: Hemorrhagic colitis (continued) Bacteria: Shiga toxin-producing Escherichia coli, including O157:H7 and O157:NM Type of Illness: Toxin-mediated infection
Talking Points:
Discuss the following:
Food involved in outbreaks
Prevention measures
Remind participants that thoroughly cooking food, especially ground beef, avoiding cross-contamination, and practicing good personal hygiene will help prevent this illness.
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29. Basic Characteristics
2• The Microworld
Basic Characteristics
Unlike bacteria, they rely on a living cell to reproduce
Unlike bacteria, they do not reproduce in food
Some may survive freezing and cooking
Can be transmitted from person to person, from people to food, and people to food-contact surfaces
Can contaminate both food and water supplies
Talking Points:
Discuss the basic characteristics of viruses.
Explain to participants that practicing good personal hygiene and minimizing bare-hand contact with ready-to-eat food is a key defense against contamination from foodborne viruses.
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30. Caused By Viruses Hepatitis A Norwalk Virus Gastroenteritis
2• The Microworld
Caused By Viruses
Hepatitis A
Norwalk Virus Gastroenteritis
Rotavirus Gastroenteritis
Talking Points:
Introduce the major foodborne illnesses caused by viruses.
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31. 2• The Microworld
Illness: Hepatitis A Virus: Hepatovirus or hepatitis A virus Type of Illness: Infection
Talking Points:
Discuss the following:
Virus associated with the illness
Type of illness
Symptoms of the illness
Sources of the illness
Point out that the human intestinal tract is the primary source of the virus.
Explain that the virus can move from the intestinal tract to food when a person fails to wash their hands after using the restroom.
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32. 2• The Microworld
Illness: Hepatitis A (continued) Virus: Hepatovirus or hepatitis A virus Type of Illness: Infection
Talking Points:
Discuss the following:
Food involved in outbreaks
Prevention measures
Emphasize the importance of good personal hygiene in preventing hepatitis A.
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33. 2• The Microworld
Illness: Norwalk Virus Gastroenteritis Virus: Norwalk and Norwalk-like viral agents Type of Illness: Infection
Talking Points:
Discuss the following:
Virus associated with the illness
Type of illness
Symptoms of the illness
Sources of the illness
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34. 2• The Microworld
Illness: Norwalk Virus Gastroenteritis (continued) Virus: Norwalk and Norwalk-like viral agents Type of Illness: Infection
Talking Points:
Discuss the following:
Food involved in outbreaks
Prevention measures
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35. Basic Characteristics
2• The Microworld
Basic Characteristics
Living organisms that need a host to survive
Small, often microscopic
Grow naturally in many animals and can be transmitted to humans
Can be killed by proper cooking and freezing
Pose a hazard to food and water
Talking Points:
Explain that a host is an animal on which the parasite lives and takes nourishment.
Point out that parasites typically are passed to humans through the meat of an animal host.
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36. Caused By Parasites Trichinosis Anisakiasis Giardiasis Toxoplasmosis
2• The Microworld
Caused By Parasites
Trichinosis
Anisakiasis
Giardiasis
Toxoplasmosis
Intestinal Cryptosporidiosis
Cyclosporiasis
Talking Points:
Introduce the major illnesses caused by parasites.
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37. 2• The Microworld
Illness: Trichinosis Parasite: Trichinella spiralis Type of Illness: Infection
Talking Points:
Discuss the following:
Parasite associated with the illness
Type of illness
Symptoms of the illness
Sources of the illness
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38. 2• The Microworld
Illness: Trichinosis (continued) Parasite: Trichinella spiralis Type of Illness: Infection
Talking Points:
Discuss the following:
Food involved in outbreaks
Prevention measures
Explain to participants that the risk of trichinosis is much lower than in previous years due to the improved way in which pigs are fed in the United States.
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39. 2• The Microworld
Illness: Anisakiasis Parasite: Anisakis simplex Type of Illness: Infection
Talking Points:
Discuss the following:
Parasite associated with the illness
Type of illness
Symptoms of the illness
Sources of the illness
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40. 2• The Microworld
Illness: Anisakiasis (continued) Parasite: Anisakis simplex Type of Illness: Infection
Talking Points:
Discuss the following:
Food involved in outbreaks
Prevention measures
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41. Molds Yeasts Mushrooms
2• The Microworld
Fungi Commonly cause food spoilage and sometimes illness
Fungi
Talking Points:
Tell participants that fungi are found in air, soil, plants, animals, water, and some food.
Molds Yeasts Mushrooms
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42. Basic Characteristics
2• The Microworld
Basic Characteristics
Spoil food and sometimes cause illness
Grow well in sweet, acidic food with low water activity
Freezing prevents or reduces their growth, but does not destroy them
Some produce toxins called aflatoxins
Pose a hazard to food
Talking Points:
Explain that some molds produce toxins that can cause allergic reactions, nervous system disorders, and kidney and liver damage.
Explain that although the FDA recommends cutting away the moldy areas in cheese (at least one inch [2.54 cm] around them), you should throw out all moldy food unless the mold is a natural part of it. Ask participants to identify some of these foods, which may include cheeses such as Bleu cheese.
Explain that although molds can be killed by heating them, toxins that may be present are not destroyed by normal cooking methods.
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43. Basic Characteristics
2• The Microworld
Basic Characteristics
Some spoil food rapidly
Grow well in sweet, acidic food with low water activity
May produce a smell or taste of alcohol as they spoil food
May appear as a pink discoloration or slime and may bubble
Talking Points:
Point out that food spoiled by yeast should be discarded.
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44. 2• The Microworld
Foodborne Infections Result when a person eats food containing pathogens, which then grow in the intestines and cause illness
Foodborne Intoxications Result when a person eats food containing toxins that cause illness
Foodborne Toxin-Mediated Infections Result when a person eats food containing pathogens, which then produce illness-causing toxins in the intestines
Talking Points:
Explain that foodborne illnesses are classified as infections, intoxications, or toxin-mediated infections, and that each occurs in a different way.
Give some examples of each classification.
Infection:
Salmonellosis
Listeriosis
Intoxication:
Botulism
Staphylococcal Gastroenteritis
Toxin-mediated infection:
Clostridium perfringens Gastroenteritis.
Point out that, typically, the symptoms of a foodborne infection do not appear immediately. However, the symptoms of a foodborne intoxication appear quickly, within a few hours.
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45. What do microorganisms need to grow?
2• The Microworld
What do microorganisms need to grow?
Talking Points:
In order to grow, microorganisms need food, the right level of acidity, the right temperature, a sufficient amount of time, and the proper amounts of oxygen and moisture.
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