Transcript
ServSafe™ Exam Prep & Study Guide
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2. The Microworld
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Section Goals
• List the types of pathogens which cause foodborne illness.
• List the factors that affect the growth of bacteria.
• List the foods most likely to become unsafe.
• List the major foodborne illnesses, their characteristics and methods of prevention.
• List additional biological hazards to food safety along with their characteristics and prevention methods.
Definitions
• TCS (Temperature Control for Safety) Foods – TCS foods are those items for which time & temperature control are vital in order to ensure the safety of the food.
• Toxin – A poison produced by a living organism.
• Spore –A form adopted by some bacteria allowing them to survive for extended periods of time in unfavorable conditions. They can change back and begin growing again once conditions are more favorable.
Pathogens
Most microorganisms are harmless. Some are even beneficial. But others (Pathogens) can cause illness. Some pathogens can make you sick. Other pathogens can produce poisons (toxins) that make you sick.
Pathogens include:• Viruses• Bacteria• Parasites• Fungi
Foods Most Likely to Become Unsafe
Though any food can be contaminated, certain foods are better for the growth of pathogens. These foods are known as TCS (Temperature Control for Safety) foods.
• Meat, Fish & Shellfish & Poultry• Eggs, Milk & Dairy Products• Soy products and Synthetic Meat Replacements• Cooked Plant Foods• Sprouts and sprout seeds• Untreated Garlic-and-Oil mixtures• Sliced Melons & Tomatoes
Characteristics of TCS Foods
These TCS Foods tend to have some common characteristics. In general, they are either historically prone to be involved in foodborne illness outbreaks or are:
• High in protein.
• Moist
• Neutral to slightly acidic.
Controlling Pathogen Growth
To control the growth of pathogens you need to keep food at the right temperature. An example of this might be refrigerating potato salad or placing soup into a hot-holding unit for service.
Like TCS foods, ready-to-eat foods also need careful handling to avoid contamination. Already cooked foods, deli-meats and cheeses, baked goods and washed fruits & vegetables are easily contaminated.
Types of Pathogens
There are four types of pathogens that can contaminate food and cause foodborne illness.
• Viruses• Bacteria• Parasites• Fungi
Viruses Viruses are the leading cause of foodborne illness. When
customers get sick from food contaminated by viruses, it’s usually because their food was handled by an employee who has that virus.
Virus Facts:• Viruses can survive refrigerator and freezer temperatures.• Viruses can contaminate food and water.• Viruses do not grow in food but once eaten can grow in a
person’s intestines.• Viruses can be transferred from person to person, person to
food, or person to food-contact surface.
Preventing Foodborne Illnesses caused by Viruses
There are several ways to help prevent the spread of viruses within your operation.
• Keep foodhandlers who are vomiting, have diarrhea, or jaundice out of the operation.
• Ensure that foodhandles wash their hands properly.• Eliminate bare-hand-contact with ready-to-eat food.
The viruses of most concern to us are Hepatitis A & Norovirus.
Disease: Hepatitis ACaused by: Hepatitus A Virus
Foods commonly involved:
Ready-to-eat foods Shellfish from
contaminated water
Prevention measures: Keep employees diagnosed
with Hepatitis A and employees with jaundice out of the operation
Proper handwashing Eliminate bare-hand contact
with ready-to-eat food. Purchase shellfish from an
approved reputable supplier.
Disease: Norovirus GastroenteritisCaused by: Norovirus
Foods commonly involved:
Ready-to-eat foods Shellfish from
contaminated water
Prevention measures: Keep employees diagnosed
with Norovirus and employees with diarrhea or vomiting out of the operation
Proper handwashing Eliminate bare-hand contact
with ready-to-eat food. Purchase shellfish from an
approved reputable supplier.
BacteriaThough viruses are the leading cause of foodborne illness, bacteria also cause
many cases of foodborne illness.
Pathogenic bacteria need six things in order to grow. Together these factors are known by the acronym, FAT TOM.
• Food.
• Acidity.
• Temperature
• Time
• Oxygen.
• Moisture
FAT TOM
FOOD
Pathogens require a source of energy like protein or carbohydrates.
ACIDITY
Pathogens grow best in low acid or neutral environments.
FAT TOM (continued)
TEMPERATURE
Pathogens grow well between 41⁰ F and 135⁰ F. This range is known as The Temperature Danger Zone.
TIME
Pathogens need time to grow. After food is in the temperature danger zone for four hours, it can make someone ill.
FAT TOM (continued)
OXYGEN
Some pathogens need oxygen to grow while others will only grow in the absence of oxygen.
MOISTURE
Pathogens need moisture in order to grow.
Bacteria
• Most bacteria are controlled by controlling time and
temperature.• If FAT TOM conditions are right bacteria can multiply
every twenty minutes.• Bacteria can survive by temporarily changing into
spore form when conditions are unfavorable.• Some bacteria make toxins as they grow and die.
Cooking and freezing may not destroy these toxins.
Disease: Bacillus Cereus GastroenteritisCaused by: Bacillus Cereus
Foods commonly involved:
Cooked vegetables Meat products Milk
Prevention measures: (Time & Temperature)
Cook food to its proper temperature.
Hold food at proper temperatures.
Cool food correctly.
Foods commonly involved:
Raw meats Unpasteurized dairy
products Ready-to-eat foods
such as deli meats, hot dogs & soft cheeses
Disease: ListeriosisCaused by: Listeria Monocytogenes
Prevention measures: Cook raw meat to its
proper temperature. Throw out any product
past its expiration or use by date.
Prevent cross contamination.
Do not use unpasteurized dairy products
Disease: Hemorrhagic ColitisCaused by: Escherichia Coli (E. Coli) O157:H& et al.
Foods commonly involved:
Ground Beef Contaminated produce
Prevention measures: Cook ground beef to its
proper temperature. Prevent cross
contamination. Buy produce from an
approved reputable supplier.
Keep employees diagnosed with hemorrhagic colitis out of the operation.
Disease: Clostridium Perfringens GastroenteritisCaused by: Clostridium Perfringens
Foods commonly involved:
Meat Poultry Soups, stews & gravies
containing meat or poultry
Prevention measures: (Time & Temperature)
Hold food at proper temperatures.
Cool food correctly.
Disease: BotulismCaused by: Clostridium Botulinum
Foods commonly involved: Improperly canned foods Reduced Oxygen
Packaging (ROP) foods Time/Temperature
abused vegetables such as baked potatoes
Untreated garlic & oil mixtures
Prevention measures: (Time & Temperature)
Hold, cool & reheat food properly.
Inspect canned foods for signs of damage.
Disease: SalmonellosisCaused by: Salmonella spp
Foods commonly involved:
Poultry Eggs Dairy Produce
Prevention measures: Cook poultry and eggs
to their proper temperatures.
Prevent cross contamination.
Keep foodhandlers diagnosed with Salmonellosis out of the operation.
Disease: ShigellosisCaused by: Shigella spp
Foods commonly involved:
Foods easily contaminated by hands such as ready-to-eat foods.
Foods that have come in contact with contaminated water
Prevention measures: (Proper Hygiene)
Keep foodhandlers who have diarrhea out of the operation.
Wash hands properly. Keep foodhandlers
diagnosed with Shigellosis out of the operation.
Disease: Staphylococcal GastroenteritisCaused by: Staphylococcus Aureus
Foods commonly involved:
Foods easily contaminated by hands such as ready-to-eat foods.
Prevention measures: (Proper Hygiene)
Wash hands properly.Cover wounds on the
hands and arms.
Disease: Vibrio Gastroenteritis and Vibrio Vulnificus Primary Scepticemia
Caused by: Vibrio Vulnificus and Vibrio Parahaemolyticus
Foods commonly involved:
Oysters from contaminated waters.
Prevention measures:Cook oysters to their
minimum internal temperature.
Parasites
Though illnesses from parasites are not as widespread as those from viruses or bacteria it is still important to guard against the threat they pose.
• Parasites can contaminate both food & water.• Parasites cannot grow in food. They need to be in the
flesh of an animal to grow and survive.• The best defense against parasites is to purchase
food from approved, reputable suppliers.
Disease: AnisakiasisCaused by: Anisakis Simplex
Foods commonly involved:
Raw and undercooked fish including: herring, cod, halibut, mackerel & Pacific salmon
Prevention measures: Cook fish to proper
temperatures. If serving raw or
undercooked fish, purchase sushi-grade fish.
Disease: CryptosporidiosisCaused by: Cryptosporidium Parvum
Foods commonly involved:
Contaminated water & produce.
Prevention measures: Use properly treated
water. Keep foodhandlers with
diarrhea out of the operation.
Wash hands.
Disease: GiardiasisCaused by: Giardia Duodenalis
Foods commonly involved:
Contaminated water & produce.
Prevention measures: (Time & Temperature)
Use properly treated water.
Keep foodhandlers with diarrhea out of the operation.
Wash hands.
Fungi
Fungi are known primarily for spoiling food but some can make people sick. They can be found in air, water, soil, plants and some food. Mold & yeast are the two fungi of primary concern.
Molds Molds spoil food and sometimes cause illness. Some
molds produce toxins, such as aflatoxins.
• Molds grow well in acidic foods with little or no moisture, such as jams & jellies and in salty meats like bacon, salami and ham.
• Throw out moldy food unless mold is a natural part of the product.
• The FDA recommends that mold on hard cheese, salami and firm produce may be cut away at least one inch (2.5 centimeters) around the moldy area.
Yeasts
Yeasts can spoil foods quickly. Signs of spoilage include a smell or taste of alcohol. The yeast itself may appear as a white or pink discoloration or slime and may bubble. Like molds, yeasts grow well in acidic foods with little moisture, such as jams & jellies, syrup, honey and fruit and fruit juices.
• Discard any food that shows signs of yeast spoilage.
Seafood Toxins
Seafood toxins cannot be smelled or tasted nor can they be destroyed by freezing or cooking.
• Fish Toxins may be a natural part of the fish or made by pathogens on the fish. Others occur when a predatory fish eats a smaller, contaminated fish that has consumed a toxin.
• Shellfish Toxins can contaminate shellfish when they consume contaminated marine algae.
Disease: Scromboid PoisoningCaused by: Histamine
Foods commonly involved:
Scromboid fish: tuna, bonito, mackerel, and mahi-mahi.
Prevention measures:Prevent time &
temperature abuse.
When Scromboid fish are time and temperature abused, bacteria on the fish make the toxin, histamine. This toxin cannot be destroyed by cooking, freezing, smoking, or curing.
Disease: Ciguatera Fish PoisoningCaused by: Ciguatoxin
Foods commonly involved:
Predatory tropical reef fish: baracuda. snapper, grouper, and jacks.
Prevention measures:Purchase fish from an
approved reputable supplier.
Ciguatoxin can be found in certain marine algae. It can build up in larger fish when they eat smaller fish that have eaten these algae. Symptoms of Ciguatera poisoning can last for months or years.
Disease: Shellfish Poisoning (Paralytic, Neurotoxic, or Amnesic)
Caused by: Saxitoxin (paralytic), Brevetoxin (neurotoxic), or Domoic Acid (amnesic)
Foods commonly involved:
Clams, Mussels, Oysters, and Scallops.
Prevention measures:Purchase shellfish from
approved, reputable suppliers.
Mushroom Toxins
Almost all cases of mushroom-borne illnesses happen when amateur mushroom hunters collect and serve wild mushrooms. Often toxic and edible mushrooms appear nearly identical to one another.
• Mushroom toxins cannot be destroyed by cooking or freezing.
• Only use mushrooms that are grown by and purchased from approved, reputable suppliers.
Plant Toxins Illnesses caused by plant toxins occur when products
are purchased from unapproved sources or if a particular product is not cooked or handled correctly. Here are some of the items that can make people sick.
• Toxic plants may be confused for their edible versions, like fool’s parsley or wild turnips.
• Honey gathered from bees that have harvested toxic nectar is toxic.
• Undercooked kidney beans can make people ill.
ServSafe Essentials
ISBN: 0135026520http://nraef.org
http://www.servsafe.com
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