Chapter 2

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Chapter 2The Microworld

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Learning Objectives

At the end of the chapter the participants must be able to:

Identify factors that affects the growth of Foodborne pathogens (FATTOMS)

Differentiate between Foodborne intoxication, infections, and toxin-mediated infections

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Microbial Contaminants

Microorganism Small, living organism

Pathogen Illness-causing microorganism

Toxin Poison

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Microbial Contaminants

Microorganisms That Can Contaminate Food and Cause Foodborne Illness

Bacteria Viruses Parasites Fungi

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What Microorganisms Need to Grow: FAT TOM

F Food Acidity Temperature A T

T O M Time Oxygen Moisture

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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

pH Scale

Neutral

Aci

dic

7.5–4.6 ideal forBacterial growth

Alk

alin

e

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Temperature Foodborne microorganisms grow

well at temperatures between 41˚F and 135˚F (5˚C and 57˚C)

135°F(57°C)

41°F(5°C)

135°F(57°C)

41°F(5°C)

135°F(57°C)

41°F(5°C)

The

Tem

pera

ture

Da n

g er Z

one

135°F(57°C)

41°F(5°C)

Time Foodborne microorganisms need

sufficient time to grow

4 hours or more in TDZ=growth high enough to cause illness

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Moisture Most foodborne microorganisms require moisture

to grow The amount of moisture available in food for this

growth is called water activity (aw) Potentially hazardous food typically has an aw of .85

or higher

Oxygen Some foodborne microorganisms require oxygen

to grow, while others grow when oxygen is absent

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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)

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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 illness-causing toxins in the intestines

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Food

Foodborne microorganisms require nutrients to grow. Specifically carbohydrates and proteins

These are found in potentially hazardous food including: Meat Poultry Dairy products Eggs

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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 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

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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 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

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Major Foodborne Illnesses Caused by Bacteria

Infections

Campylobacteriosis Salmonellosis Shigellosis Listeriosis Vibrio parahaemolyticus Gastroenteritis Vibrio vulnificus Primary Septicemia/Gastroenteritis

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Illness:Campylobacteriosis Bacteria: Campylobacter jejuni

Most Common Symptoms

Diarrhea

Abdominal Cramps

Fever

Headache

Poultry Water contaminated

with the bacteria

Diarrhea (may be bloody)

Abdominal cramps Fever Headache

Infection: Campylobacteriosis

Commonly Associated Food Most Common Symptoms

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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.

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Infection: Salmonellosis

Illness: Salmonellosis Bacteria:Salmonella spp.


Poultry and eggs Dairy products Beef

Diarrhea Abdominal cramps Vomiting Fever

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Preventing Salmonellosis


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.

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Infection: Shigellosis

Illness: Shigellosis Bacteria:Shigella spp.

Most Common SymptomsCommonly Associated Food Most Common Symptoms

Food easily contaminated by hands

Food in contact with contaminated water (i.e., produce)

Bloody diarrhea Abdominal pain

and cramps Fever

(occasionally)

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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

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Illness: Listeriosis Bacteria:Listeria monocytogenes

Infection: Listeriosis

Most Common Symptoms

Raw meat Unpasteurized milk and

milk products Ready-to-eat food

including: Deli meats Hot dogs Soft cheese

Pregnant women Spontaneous

abortion of the fetus

Newborns Sepsis Pneumonia Meningitis


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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

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Infection: Vibrio parahaemolyticus Gastroenteritis

Illness: Vibrio parahaemolyticus Gastroenteritis

Bacteria:Vibrio parahaemolyticus


Raw or partially cooked oysters

Diarrhea and abdominal cramps

Nausea and vomiting

Low grade fever and chills

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Preventing Vibrio parahaemolyticus Gastroenteritis

Most Important Prevention Measures

Purchase oysters from approved, reputable suppliers

Cook oysters to the required minimum internal temperature

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Infection: Vibrio vulnificus Primary Septicemia


Fever and chills Nausea Skin lesions Diarrhea and

vomiting possible


(People with liver disease and diabetes)

Illness: Vibrio vulnificus Primary Septicemia

Bacteria:Vibro vulnificus

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Illness: Vibrio vulnificusGastroenteritis

Bacteria:Vibrio vulnificus

Infection: Vibrio vulnificus Gastroenteritis


(Otherwise healthy people) Diarrhea Abdominal cramps


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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

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Intoxications

Bacillus cereus Gastroenteritis

Staphylococcal Gastroenteritis

Botulism

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Intoxication: Bacillus cereus Gastroenteritis

Illness: Bacillus cereus Gastroenteritis

Bacteria:Bacillus cereus

(Diarrheal Toxin)Most Common Symptoms

Cooked corn Cooked potatoes Cooked vegetables Meat products

Watery diarrhea Abdominal cramps

and pain Vomiting is absent

Most Common SymptomsCommonly Associated Food

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Illness: Bacillus cereus Gastroenteritis

Bacteria:Bacillus cereus

(Emetic Toxin)

Intoxication: Bacillus cereus Gastroenteritis

Cooked rice dishes including: Fried rice Rice pudding

Nausea Vomiting

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Preventing Bacillus cereus Gastroenteritis


Cook food to required minimum internal temperatures

To prevent the growth of the bacteria:

Hold food at the proper temperature

Cool food properly

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Illness: Staphylococcal Gastroenteritis

Bacteria:Staphylococcus aureus

Intoxication: Staphylococcal Gastroenteritis


Salads containing potentially hazardous food: Egg, tuna,

chicken, macaroni

Deli meats

Nausea Vomiting and

etching Abdominal cramps


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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

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Intoxication: Botulism

Illness: Botulism Bacteria:Clostridium botulinum


Improperly canned food

ROP food Temperature abused

vegetables like: Baked potatoes Untreated garlic-

and-oil mixtures

Initially: Nausea and VomitingLater: Weakness Double vision Difficulty speaking and

swallowing

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Preventing Botulism

Most Important Prevention Measures:

Hold, cool, and reheat food properly

Inspect canned food for damage

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Toxin-Mediated Infections:

Clostridium perfringens Gastroenteritis

Hemorrhagic Colitis

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Illness: Clostridium perfringens Gastroenteritis

Bacteria:Clostridium perfringens

Meat Poultry Meat and poultry

dishes: Stews Gravies

Diarrhea Severe abdominal

pain Fever and vomiting

are absent

Toxin-Mediated Infection: Clostridium perfringens Gastroenteritis


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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

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Illness: Hemorrhagic Colitis Bacteria: Shiga toxin-producing

Escherichia coli

Toxin-Mediated Infection: Hemorrhagic Colitis


Ground beef (raw and undercooked)

Contaminated produce

Diarrhea (eventually becomes bloody)

Abdominal cramps Severe cases can

result in hemolytic uremic syndrome (HUS)

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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

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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

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Major Foodborne Illnesses Caused by Viruses

Viral Foodborne Illnesses

Hepatitis A

Norovirus Gastroenteritis

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Infection: Hepatitis A

Illness: Hepatitis A Virus: Hepatitis A


Ready-to-eat food including: Deli meats Produce Salads

Raw and partially cooked shellfish

Initially: Fever (mild) General weakness Nausea Abdominal painLater: Jaundice

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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

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Infection: Norovirus Gastroenteritis

Illness: Norovirus Gastroenteritis Virus: Norovirus


Ready-to-eat food Shellfish

contaminated by sewage

Vomiting Diarrhea Nausea Abdominal

cramps

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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

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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

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Major Foodborne Illnesses Caused by Parasites

Parasitic Foodborne Illnesses

Anisakiasis

Cyclosporiasis

Cryptosporidiosis

Giardiasis

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Illness: Anisakiasis Parasite: Anisakis simplex


Raw and undercooked: Herring Cod Halibut Mackerel Pacific salmon

Non-invasive Tingling in throat Coughing up worms

Invasive Stomach pain Nausea Vomiting Diarrhea

Infection: Anisakiasis

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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

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Infection: Cyclosporiasis

Illness: Cyclosporiasis Parasite: Cyclospora cayetanensis


Produce irrigated or washed with water containing the parasite

Nausea (mild to severe)

Abdominal cramping Mild fever Diarrhea alternating

with constipation

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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

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Illness: Cryptosporidiosis Parasite: Cryptosporidium parvum

Infection: Cryptosporidiosis


Untreated or improperly treated water

Contaminated produce

Watery diarrhea Stomach cramps Nausea Weight loss

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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

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Infection: Giardiasis

Illness: Giardiasis Parasite: Giardia duodenalis

Improperly treated water

Initially: Fever

Later: Loose stools Abdominal

cramps Nausea


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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

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Fungi

Fungi

Commonly cause food spoilage and sometimes illness

Molds Yeasts

Fungi

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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

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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

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Apply Your Knowledge: What I Need to Grow!

Which conditions typically support the growth of microorganisms? Food that is high in fat Food that contains protein pH of 9.0 Temperature of 155F (68C) or higher Dry environment

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2

3

4

5

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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

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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

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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

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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

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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

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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

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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

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Documents

Chapter 2