Transcript Bacteria

Sanitation
Hazards
7
Objective
• Summarize the importance of working with
food safely.
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Importance of Safe Food Handling
• Foodborne illness can result from improper
food handling
• An outbreak occurs when two or more
people eat the same food and get the same
foodborne illness
continued
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Importance of Safe Food Handling
• The goal of foodservice
employees is to serve
food that is free of
contamination
• Proper sanitation
prevents contamination
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Objectives
• Differentiate among biological, chemical,
and physical hazards.
• Classify the sources of biological hazards
and ways to control their growth.
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Biological Hazards
• Most biological hazards are too small to
see, and sometimes cannot be detected by
smell or taste
• Biological hazards, or pathogens, include
harmful
– bacteria
– viruses
– fungi
– parasites
– fish toxins
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Bacteria
• Responsible for most outbreaks, bacteria need
water, food, and favorable temperatures to
thrive
• Potentially hazardous foods (PHF) require time
and temperature control for safety (TCS) to
limit the growth of pathogens
• Controlling the time they are exposed to unsafe
temperatures helps limit bacteria growth
continued
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Bacteria
• Different types of bacteria have different
needs for growth
– aerobic bacteria require oxygen
– anaerobic bacteria thrive without oxygen
– facultative bacteria grow with or without oxygen
continued
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Bacteria
• Bacteria produce rapidly
by dividing
• Some bacteria have the
ability to form spores
continued
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Bacteria
• Pathogenic bacteria cause foodborne illness
in humans
– infection
– intoxication
– toxin mediated infection
continued
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Bacteria
• Control any or all of the following to create
unfavorable conditions for bacterial growth
– Food source. Protein is a favored food source
of bacteria
– pH. Bacteria remain active between a pH of
4.6 to 7
– Temperature. Bacteria reproduce rapidly in
the temperature danger zone, between 41 F
and 135 F (5 C and 57 C)
continued
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Bacteria
– Time. Potentially hazardous foods should not be
kept in the temperature danger zone for more
than four hours
– Atmosphere. Removing oxygen from their
atmosphere stops the growth of aerobic bacteria
– Water. Bacteria are sensitive to water activity (aw)
and require a high level for growth
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Viruses
• Viruses can survive but cannot reproduce
without a cell host
• Most viruses are destroyed by high heat, but
are not affected by water activity or pH
• Two viruses that concern foodservice are
– hepatitis A
– Norovirus (Norwalk virus)
continued
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Viruses
• Viral contamination can be avoided by
– practicing excellent personal hygiene
– washing raw vegetables before preparation and
eating
– avoiding shellfish harvested from polluted waters
– purchasing food from reputable suppliers
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Fungi
• Edible mushrooms are a type of fungi that
are highly valued in the professional kitchen
• Other types, such as poisonous mushrooms,
yeasts, and molds, can cause food
contamination
• Always purchase wild mushrooms from a
reputable source
continued
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Fungi
• Yeast
– Wild yeast growing unintentionally can cause
contamination
– Slime, discoloration, bubbles, and an alcoholic
smell are signs of a yeast contamination
– Yeast is killed when heated above 136 F (58 C)
continued
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Fungi
• Mold
– Although most are not poisonous, a few molds
produce toxins that are dangerous to humans
– Mold can be killed at temperatures above 140 F
(60 C), but their toxins may not be affected
– Moldy food should always be discarded
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Parasites
• Parasites can be found in meat and fish
• Trichinella spiralis is
– the cause for the disease called trichinellosis
– rarely caused from pork and is more often caused
by eating undercooked game meats
– killed by cooking pork to an internal temperature of
145 F (63 C) with a three-minute rest
– killed in whole cuts and ground game by cooking to
an internal temperature of 160 F (71 C)
continued
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Parasites
• Fish harbor parasites such as anisakis, and
certain varieties of cestodes (tapeworms)
and trematodes (flukes)
– Kill these parasites by cooking fish to an internal
temperature of 140 F (60 C)
– Freezing infested fish at –31 F (–35 C) for
15 hours or –4 F (–20 C) for seven days also
kills fish parasites
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Fish Toxins
• Fish toxins are poisons within the fish’s flesh
that can cause illness when eaten
• Two illnesses caused by fish toxins that
concern foodservice are
– ciguatera: commonly associated with red
snapper, grouper, and barracuda
– scombroid poisoning: commonly associated with
yellowfin tuna, skipjack, bonito, and mackerel
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Objectives
• Differentiate among biological, chemical,
and physical hazards.
• Recognize chemical hazards and explain
how to prevent them.
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Chemical Hazards
• There are many chemical hazards in the
kitchen, including
– metals
– agricultural chemicals
– kitchen chemicals
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Metals
• Certain metals found in cookware can leach,
or seep, and become a chemical hazard
• Copper pans are lined with tin to prevent
contamination
• Galvanized steel should never be used in
food preparation, because it contains zinc
continued
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Metals
• Chipped enamel cookware can be another
source of metal poisoning
• Fish from polluted waters can contain unsafe
levels of heavy metals such as mercury
• Always purchase fish from reputable sources
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Agricultural Chemicals
• The exterior of fruits and vegetables may be
tainted with insecticides, pesticides, and
herbicides
• Prevent this chemical contamination by
washing and peeling produce
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Kitchen Chemicals
• Chemicals such as cleaning supplies,
bleach, grease cutters, and polishes are
potential sources of contamination
continued
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Kitchen Chemicals
• Follow safety precautions to prevent most
chemical contaminations
– Store chemicals in clearly marked containers or
leave in original containers
– Do not store food in containers that previously
held chemicals
– Use according to manufacturer’s instructions
– Store in an area separate from food preparation
or storage
continued
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Kitchen Chemicals
• Safety precautions (continued)
– Never randomly mix chemicals
– Dispose according to the manufacturer’s
directions
– Ask a supervisor how to use a chemical product
if uncertain
– Call a poison control hotline immediately, refer
to material safety data sheets (MSDS), and
notify a supervisor if poisoning is suspected
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Objectives
• Differentiate among biological, chemical,
and physical hazards.
• Explain physical hazards and how to
prevent them.
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Physical Hazards
• Physical hazards are easily prevented and
often visible to the naked eye
• Common physical hazards include
– glass
– staples
– metal shards
– toothpicks
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Objective
• Recognize eight common food allergens.
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Food Allergens
• Food allergies are common
• An allergy occurs when the body
misinterprets a normally harmless protein as
a hazardous substance
• The misinterpreted protein is an allergen
continued
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Food Allergens
• There are eight common food allergens:
– dairy products
– wheat products
– fish
– shellfish
– peanut and
peanut products
– soy and soy
derivatives
– eggs
– seeds
– tree nuts
continued
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Food Allergens
• Allergies do not affect all people in the same
way
• When a customer notifies a restaurant server
of an allergy, the kitchen staff must analyze
everything that is served to that customer
• The staff must also ensure cross-contact
does not occur
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Review
• Define foodborne illness and explain the
term outbreak
– Foodborne illness is sickness caused by
eating unsafe food
– An outbreak occurs when two or more people
eat the same food and get the same sickness
continued
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Review
• List the different types of biological
hazards
– bacteria
– viruses
– fungi
– parasites
– fish toxins
continued
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Permission granted to reproduce for educational use only.
Review
• Explain the difference between aerobic,
anaerobic, and facultative bacteria
– Aerobic bacteria require oxygen
– Anaerobic thrive without oxygen
– Facultative grow with or without oxygen
continued
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Review
• Describe the factors involved in controlling
bacteria growth
– food source, pH, temperature, time,
atmosphere, and water
continued
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Review
• List the different types of chemical
hazards
– metals, agricultural chemicals, kitchen
chemicals
continued
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Review
• What is the purpose of a material safety
data sheet (MSDS)?
– to list the composition of a chemical product,
proper procedures for storage and handling,
and what to do in case of an emergency
continued
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Review
• List some examples of physical hazards
– glass, staples, metal shards, toothpicks
continued
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Permission granted to reproduce for educational use only.
Review
• List eight common types of food allergens
– dairy products; wheat products, including
flour; fish; shellfish; peanut and peanut
products; soy and soy derivatives; eggs;
seeds; tree nuts
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Permission granted to reproduce for educational use only.