The Microworld
2-1
Apply Your Knowledge: Test Your Food Safety Knowledge
1. True or False: Bacillus cereus is commonly
associated with cereal crops, such as rice
2. True or False: A foodborne intoxication results when
a person eats food containing pathogens, which then
grow in the intestines and cause illness
3. True or False: Cooking food to the required
minimum internal temperature can help avoid
listeriosis
4. True or False: A person with shigellosis may
experience bloody diarrhea
5. True or False: Highly acidic food typically does not
support the growth of foodborne microorganisms
2-2
Microbial Contaminants
Microorganism

Small, living organism
Pathogen

Illness-causing microorganism
Toxin

Poison
2-3
Microbial Contaminants
Microorganisms That Can Contaminate
Food and Cause Foodborne Illness
Bacteria
Viruses
Parasites
Fungi
2-4
What Microorganisms Need to Grow: FAT TOM
Food
F
Acidity
A
Temperature
T
O
M
Time
Oxygen
T
Moisture
2-5
What Microorganisms Need to Grow: FAT TOM
Food

Foodborne microorganisms require
nutrients to grow. Specifically
carbohydrates and proteins

These are found in potentially
hazardous food including:

Meat

Poultry

Dairy products

Eggs
F
Food
2-6
What Microorganisms Need to Grow: FAT TOM
Acidity

Foodborne microorganisms grow
best in food that has a neutral or
slightly acidic pH (7.5 to 4.6)

Most food falls into this range
A
Acidity
Acidic
pH Scale
Alkaline
Neutral
2-7
What Microorganisms Need to Grow: FAT TOM
Temperature

Foodborne microorganisms grow
well at temperatures between 41˚F
and 135˚F (5˚C and 57˚C)
T
Temperature
135°F
(57°C)
41°F
(5°C)
2-8
What Microorganisms Need to Grow: FAT TOM
Time

Foodborne microorganisms need
sufficient time to grow

4 hours or more in TDZ=growth high
enough to cause illness
T
Time
2-9
What Microorganisms Need to Grow: FAT TOM
Oxygen

Some foodborne microorganisms
require oxygen to grow, while
others grow when oxygen is absent
O
Oxygen
2-10
What Microorganisms Need to Grow: FAT TOM
Moisture

Most foodborne microorganisms require
moisture to grow

The amount of moisture available in
food for this growth is called water
activity (aw)

M
Moisture
Potentially hazardous food typically has
an aw of .85 or higher
2-11
Controlling the Growth of Microorganisms
The two conditions you can control:


Temperature

Refrigerate or freeze food properly

Cook food properly
Time

Minimize time food spends
in the temperature danger zone (TDZ)
2-12
Apply Your Knowledge: What I Need to Grow!
Which conditions typically support
the growth of microorganisms?
1
Food that is high in fat
2
Food that contains protein
3
pH of 9.0
4
Temperature of 155F (68C) or higher
5
Dry environment
2-13
Classifying Foodborne Illness
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 illnesscausing toxins in the intestines
2-14
Bacteria That Cause Foodborne Illness
Basic Characteristics

Living, single-celled organism

Can be carried by food, water, soil,
animals, humans, or insects

Can reproduce very rapidly under
favorable conditions
2-15
Bacteria That Cause Foodborne Illness
Basic Characteristics: continued

Some survive freezing

Some change into a different form called
spores to protect themselves

Some spoil food; others cause illness

Some produce toxins that cause illness
2-16
Spores
Certain bacteria can change into
a different form, called spores,
to protect themselves
Spores

Form when nutrients are not available

Are commonly found in soil and
contaminate food grown there

Can contaminate meat, poultry, fish, and
other food exposed to soil or dust
2-17
Spores
Spores

Can resist heat, allowing them to survive
cooking temperatures

Can revert back to a form capable of growth
when:

Food is not stored at the proper
temperature

Food is not held or cooled properly
2-18
Major Foodborne Illnesses Caused by Bacteria
Infections

Campylobacteriosis

Salmonellosis

Shigellosis

Listeriosis

Vibrio parahaemolyticus Gastroenteritis

Vibrio vulnificus Primary
Septicemia/Gastroenteritis
2-19
Infection: Campylobacteriosis
Illness: Campylobacteriosis
Bacteria: Campylobacter
Commonly Associated Food
jejuni
MostCommon
Common
Symptoms
Most
Symptoms

Poultry


Water
contaminated with
the bacteria
Diarrhea (may be
Diarrhea
bloody)
Abdominal Cramps

Fever
Abdominal
cramps

Headache
Fever

Headache
2-20
Preventing Campylobacteriosis
To reduce the bacteria in food:

Cook food, particularly poultry, to
required minimum internal temperatures
To prevent the transfer of the
bacteria:

Prevent cross-contamination between
raw poultry and ready-to-eat food.
2-21
Infection: Salmonellosis
Illness: Salmonellosis
Bacteria: Salmonella spp.
Commonly Associated Food
Most Common Symptoms

Poultry and eggs

Diarrhea

Dairy products


Beef
Abdominal
cramps

Vomiting

Fever
2-22
Preventing Salmonellosis
To reduce the bacteria in food:

Cook raw beef, poultry, and eggs to
required minimum internal temperatures.
To prevent the transfer of the
bacteria:

Minimize cross-contamination between
raw meat and poultry and ready-to-eat
food.

Exclude foodhandlers diagnosed with
salmonellosis.
2-23
Infection: Shigellosis
Illness: Shigellosis
Bacteria: Shigella spp.
Commonly Associated Food


Food easily
contaminated by
hands
Food in contact with
contaminated water
(i.e., produce)
MostCommon
Common
Symptoms
Most
Symptoms

Bloody diarrhea

Abdominal pain
and cramps

Fever
(occasionally)
2-24
Preventing Shigellosis
To prevent the transfer of the
bacteria:

Exclude foodhandlers if they:

Have diarrhea

Have been diagnosed with
shigellosis

Wash hands when necessary

Control flies inside and outside the
establishment
2-25
Infection: Listeriosis
Illness: Listeriosis
Bacteria: Listeria
Commonly Associated Food

Raw meat

Unpasteurized milk and
milk products

Ready-to-eat food
including:

Deli meats

Hot dogs

Soft cheese
monocytogenes
MostCommon
Common
Symptoms
Most
Symptoms

Pregnant women


Spontaneous
abortion of the fetus
Newborns

Sepsis

Pneumonia

Meningitis
2-26
Preventing Listeriosis
It is critical to:

Discard product that has passed its
use-by or expiration date

Avoid using unpasteurized dairy
products
To reduce the bacteria in food:

Cook raw meat to required minimum
internal temperatures
To prevent the transfer of the
bacteria:

Prevent cross-contamination between
raw or undercooked and ready-to-eat
food
2-27
Infection: Vibrio parahaemolyticus Gastroenteritis
Illness:
Vibrio parahaemolyticus
Gastroenteritis
Bacteria: Vibrio
parahaemolyticus
Commonly Associated Food
Most Common Symptoms

Raw or partially
cooked oysters

Diarrhea and
abdominal
cramps

Nausea and
vomiting

Low grade fever
and chills
2-28
Preventing Vibrio parahaemolyticus Gastroenteritis
Most Important Prevention
Measures

Purchase oysters from approved,
reputable suppliers

Cook oysters to the required minimum
internal temperature
2-29
Infection: Vibrio vulnificus Primary Septicemia
Illness:
Vibrio vulnificus Primary
Septicemia
Bacteria: Vibro
Commonly Associated Food

Raw or partially
cooked oysters
vulnificus
Most Common Symptoms
(People with liver disease
and diabetes)




Fever and chills
Nausea
Skin lesions
Diarrhea and
vomiting possible
2-30
Infection: Vibrio vulnificus Gastroenteritis
Illness:
Vibrio vulnificus
Gastroenteritis
Bacteria: Vibrio
Commonly Associated Food

Raw or partially
cooked oysters
vulnificus
Most Common Symptoms
(Otherwise healthy
people)
 Diarrhea
 Abdominal cramps
2-31
Preventing Vibrio vulnificus Septicemia/Gastroenteritis
Most Important Prevention
Measures

Purchase oysters from approved,
reputable suppliers.

Cook oysters to the required minimum
internal temperature.

Inform people at risk to consult a
physician before regularly consuming
raw or partially cooked oysters
2-32
Major Foodborne Illnesses Caused by Bacteria
Intoxications

Bacillus cereus Gastroenteritis

Staphylococcal Gastroenteritis

Botulism
2-33
Intoxication: Bacillus cereus Gastroenteritis
Illness:
Bacillus cereus
Gastroenteritis
Bacteria: Bacillus
cereus
(Diarrheal Toxin)
Commonly Associated Food
Most Common Symptoms
Most Common Symptoms

Cooked corn

Watery diarrhea

Cooked potatoes


Cooked vegetables
Abdominal cramps
and pain

Vomiting is absent

Meat products
2-34
Intoxication: Bacillus cereus Gastroenteritis
Illness:
Bacillus cereus
Gastroenteritis
Bacteria: Bacillus
cereus
(Emetic Toxin)
Commonly Associated Food

Cooked rice dishes
including:

Fried rice

Rice pudding
Most Common Symptoms

Nausea

Vomiting
2-35
Preventing Bacillus cereus Gastroenteritis
To reduce the bacteria in food:

Cook food to required minimum internal
temperatures
To prevent the growth of the
bacteria:

Hold food at the proper temperature

Cool food properly
2-36
Intoxication: Staphylococcal Gastroenteritis
Illness: Staphylococcal
Gastroenteritis
Bacteria: Staphylococcus
aureus
Most Common Symptoms
Commonly Associated
Food
Commonly
Associated
FoodMost Common Symptoms

Salads containing
potentially
hazardous food:

Nausea

Vomiting and
retching
Egg, tuna,
chicken,
macaroni

Abdominal cramps


Deli meats
2-37
Preventing Staphylococcal Gastroenteritis
To prevent the transfer
of the bacteria to food:

Wash hands after touching the body

Cover cuts on hands and arms

Restrict foodhandlers with infected cuts
on hands and arms
To prevent the growth of the
bacteria in food:

Minimize the time food spends in the
TDZ

Cook, hold, and cool food properly
2-38
Intoxication: Botulism
Illness: Botulism
Bacteria: Clostridium
Commonly Associated Food

Improperly canned food

ROP food

Temperature abused
vegetables like:

Baked potatoes

Untreated garlicand-oil mixtures
botulinum
Most Common Symptoms
Initially:
 Nausea and Vomiting
Later:
 Weakness
 Double vision
 Difficulty speaking and
swallowing
2-39
Preventing Botulism
Most Important
Prevention Measures:

Hold, cool, and reheat food properly

Inspect canned food for damage
2-40
Major Foodborne Illnesses Caused by Bacteria
Toxin-Mediated Infections:

Clostridium perfringens Gastroenteritis

Hemorrhagic Colitis
2-41
Toxin-Mediated Infection: Clostridium perfringens Gastroenteritis
Illness:
Clostridium perfringens
Gastroenteritis
Bacteria: Clostridium
Commonly Associated Food
Most Common Symptoms

Meat


Poultry


Meat and poultry
dishes:


Stews

Gravies
perfringens
Diarrhea
Severe abdominal
pain
Fever and vomiting
are absent
2-42
Preventing Clostridium perfringens Gastroenteritis
To prevent growth of the bacteria
(especially in meat dishes):

Cool and reheat food properly

Hold food at the proper temperature
2-43
Toxin-Mediated Infection: Hemorrhagic Colitis
Illness: Hemorrhagic Colitis
Bacteria: Shiga toxin-producing
Escherichia coli
Commonly Associated Food
MostCommon
Common
Symptoms
Most
Symptoms

Ground beef (raw
and undercooked)

Diarrhea (eventually
becomes bloody)

Contaminated
produce

Abdominal cramps

Severe cases can
result in hemolytic
uremic syndrome
(HUS)
2-44
Preventing Hemorrhagic Colitis
To reduce the bacteria in food:

Cook food, particularly ground beef, to
required minimum internal temperatures
To prevent the transfer of the bacteria to food:

Prevent cross-contamination between raw
meat and ready-to-eat food

Exclude employees from the establishment if:

They have diarrhea

They have been diagnosed with hemorrhagic colitis
2-45
Apply Your Knowledge: Who Am I?
1. Identify the bacteria:
 Many farm animals naturally carry me
 I have been found in produce that has come in
contact with animal waste
 I am often associated with poultry and eggs
 I can produce diarrhea and vomiting in those who
consume me
2. Identify the bacteria:
 I am found in the waters of the Gulf of Mexico
 I have been associated with raw oysters
 I can produce two different illnesses
 Purchasing oysters from approved, reputable
suppliers can prevent me
2-46
Apply Your Knowledge: Who Am I?
3. Identify the bacteria:
 I am found in the soil
 I have been associated with rice
 I can produce two different types of toxins that
cause illness
 Cooking food to required minimum internal temperatures
can destroy me
4. Identify the bacteria:
 I form spores
 The toxins I produce cause illness
 I have been associated with meat stews
 I can produce diarrhea and severe abdominal pain
 I am carried in the intestines of animals and humans
2-47
Apply Your Knowledge: Who Am I?
5. Identify the bacteria:

I do not need oxygen to grow

I can cause double vision and difficulty swallowing

I am commonly associated with produce from the soil

I produce a deadly toxin when food is temperature
abused
2-48
Basic Characteristics of Viruses
Viruses

Some may survive freezing

Can be transmitted from:

Person to person

People to food

People to food-contact surfaces

Usually contaminate food through a
foodhandler’s improper hygiene

Can contaminate both food and water
supplies
2-49
Major Foodborne Illnesses Caused by Viruses
Viral Foodborne Illnesses

Hepatitis A

Norovirus Gastroenteritis
2-50
Infection: Hepatitis A
Illness: Hepatitis A
Virus:
Hepatitis A
Commonly Associated Food


Ready-to-eat food
including:

Deli meats

Produce

Salads
Raw and partially
cooked shellfish
MostCommon
Common
Symptoms
Most
Symptoms
Initially:
 Fever (mild)
 General weakness
 Nausea
 Abdominal pain
Later:
 Jaundice
2-51
Preventing Hepatitis A
To prevent the transfer of the virus to food:

Wash hands properly

Exclude employees who have jaundice or
hepatitis A

Minimize bare-hand contact with ready-to-eat food
Other prevention measures:

Purchase shellfish from approved, reputable
suppliers

Inform high-risk populations to consult a physician
before regularly consuming raw or partially cooked
shellfish
2-52
Infection: Norovirus Gastroenteritis
Illness: Norovirus Gastroenteritis
Virus:
Norovirus
Commonly Associated Food
MostCommon
Common
Symptoms
Most
Symptoms

Ready-to-eat food

Vomiting

Shellfish
contaminated by
sewage

Diarrhea

Nausea

Abdominal
cramps
2-53
Preventing Norovirus Gastroenteritis
To prevent the transfer of the
virus to food:

Exclude foodhandlers with diarrhea
and vomiting

Exclude employees who have been
diagnosed with Norovirus Gastroenteritis

Wash hands properly
Other prevention measures:

Purchase shellfish from approved,
reputable suppliers
2-54
Basic Characteristics of Parasites
Parasites

Are living organisms that need a host
to survive

Are small, often microscopic

Infect many animals and can be
transmitted to humans

Are a hazard to food and water
2-55
Major Foodborne Illnesses Caused by Parasites
Parasitic Foodborne Illnesses

Anisakiasis

Cyclosporiasis

Cryptosporidiosis

Giardiasis
2-56
Infection: Anisakiasis
Illness: Anisakiasis
Parasite:
Anisakis simplex
Commonly Associated Food
Raw and undercooked:
 Herring
 Cod
 Halibut
 Mackerel
 Pacific salmon
Most Common Symptoms
Most Common Symptoms
Non-invasive
 Tingling in throat
 Coughing up worms
Invasive
 Stomach pain
 Nausea
 Vomiting
 Diarrhea
2-57
Preventing Anisakiasis
Most Important Prevention Measures

Cook fish to required minimum internal
temperatures

Purchase fish from approved, reputable suppliers
If fish will be served raw or undercooked:

Purchase sushi-grade fish

Ensure sushi-grade fish has been frozen
properly by the supplier
2-58
Infection: Cyclosporiasis
Illness: Cyclosporiasis
Parasite:
Cyclospora cayetanensis
Commonly Associated Food

Produce irrigated or
washed with water
containing the
parasite
Most Common Symptoms

Nausea (mild to
severe)

Abdominal
cramping

Mild fever

Diarrhea alternating
with constipation
2-59
Preventing Cyclosporiasis
It is critical to:

Purchase produce from approved,
reputable suppliers
To prevent the transfer
of the parasite to food:

Exclude foodhandlers with diarrhea

Wash hands properly to minimize the
risk of cross-contamination
2-60
Infection: Cryptosporidiosis
Illness: Cryptosporidiosis
Parasite:
Cryptosporidium parvum
Commonly Associated Food


Most Common Symptoms
Untreated or
improperly treated
water

Watery diarrhea

Stomach cramps
Contaminated
produce

Nausea

Weight loss
2-61
Preventing Cryptosporidiosis
It is critical to:

Purchase produce from approved, reputable
suppliers

Use properly treated water
To prevent the transfer of the parasite to
food:

Exclude foodhandlers with diarrhea

Wash hands properly to minimize the risk of
cross-contamination
2-62
Infection: Giardiasis
Illness: Giardiasis
Parasite:
Giardia duodenalis
Commonly Associated Food

Improperly treated
water
Most Common Symptoms
Initially:
 Fever
Later:
 Loose stools
 Abdominal
cramps
 Nausea
2-63
Preventing Giardiasis
Most Important Prevention Measure

Use properly treated water
To prevent the transfer
of the parasite to food:

Exclude foodhandlers with diarrhea

Wash hands properly to minimize the risk of
cross-contamination
2-64
Apply Your Knowledge: Who Am I?
1. Identify the virus or parasite:
 I can produce a mild fever and general weakness
 I am primarily found in the feces of infected people
 I am more commonly associated with ready-to-eat food
items
 Purchasing shellfish from an approved supplier can be a
safeguard against me
2. Identify the virus or parasite:
 I can produce a fever and loose stools
 I have been found in improperly treated water
 Excluding foodhandlers with diarrhea can
be a safeguard against me
 I am easily spread in day-care centers
2-65
Apply Your Knowledge: Who Am I?
3. Identify the virus or parasite:
 Cooking seafood can destroy me
 I have been found in herring
 Sometimes I produce a tingling in the throat
 Purchasing seafood from approved suppliers can
prevent me
4. Identify the virus or parasite:
 I am often associated with ready-to-eat food
 Proper handwashing is essential to prevent me
 I am primarily found in the feces of the people I infect
 People become contagious within a few hours of
eating me
2-66
Apply Your Knowledge: Who Am I?
5. Identify the virus or parasite:

I can cause stomach cramps and weight loss

I am found in cows and other herd animals

I am commonly spread from person to person

Purchasing produce from approved suppliers is critical
to prevent me
2-67
Fungi
Fungi

Commonly cause food spoilage
and sometimes illness
Fungi
Molds
Yeasts
2-68
Basic Characteristics of Mold
Mold

Spoils food and sometimes causes
illness

Grows well in acidic food with low water
activity

Is not destroyed by freezing

Can produce toxins such as aflatoxins
2-69
Basic Characteristics of Yeast
Yeast

Can spoil food rapidly

May produce a smell or taste of
alcohol as it spoils food

May appear as a pink discoloration
or slime and may bubble
2-70