servsafe chapter 2
DESCRIPTION
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Learning Objectives
Define key terms: Microorganisms, Pathogen, Toxin, Spoilage Microorganisms
Differentiate the types of pathogens Describe the growth curve of bacteria Enumerate the conditions of the growth
microorganisms
Disease-Causing Microorganisms and the Conditions They Need to Grow
Barriers for Controlling the Growth of Microorganisms
Microorganism Small living organism
Pathogen A disease-causing microorganism
Toxin Poison
Spoilage Microorganism Microorganism that causesspoilage, but not illness
Bacteria Viruses Parasites Fungi
Microorganisms That Can ContaminateFood and Cause Foodborne Illness
Living, single-celled Carried by food, water, humans and insects Can reproduce rapidly Some survive freezing Some form spores Some spoil food; others cause disease Some cause illness by producing toxins
Growth Stages of Bacteria
Bacterial Growth
What Microorganisms Need to Grow
Food Microorganisms require nutrients to grow
Proteins
Carbohydrates
Acidity Pathogenic bacteria grow well at a pH of 4.6 to 7.5
Raw Chicken 5.5–6.4
Egg Yolks 6.0–6.3
Butter 6.0–6.8
Temperature The Temperature Danger Zone(TDZ) = 41ºF to 140ºF (5ºC to 60ºC)
Most microorganisms grow well in the TDZ
Some survive and grow outside the TDZ
Time Pathogenic microorganisms can grow to high levels if they remain in the TDZ for more than four hours
Oxygen Microorganisms have differentoxygen needs for growth
Aerobic needs oxygen to grow
Anaerobic grows only when oxygen is absent
Facultative can grow with or without oxygen
Moisture Most potentially hazardous foods have a water activity of .85 or above
Raw Chicken and Butter Water Activities of .95–1.0
Barriers That Control the Growthof Microorganisms
Make the foodmore acidic
Raise or lowerthe temperature of the food
Lower the water activity
Lessen the time in the TDZ
DIAGRAMATIC SCHEME
Physical
S a lm o n e lla
L is te riam o n o cy to ge n e s
V ib rio sp p .
C a m p y lo ca c te rje ju n i
Y e rs in iae n te ro co lit ica
In fec tion
S ta p h y lo co ccu sa u re u s
C lo s trid iu mb o tu lin u m
B a c illu s ce re u s(em etic )
In toxica tion
B a c illu s ce re u s(d ia rrh e a l)
S h ige lla sp p .
C lo s trid iu mp e rfrin ge n s
E sch e rich ia co li0 1 5 7 H 7
Toxin -M ed ia tedIn fec tion
B ac teria V iru ses
M old s(in c lu d in g
m u sh room s)
Y eas ts
F u n g i P aras ites
Biological
F ood A d d itivesF lavors
C o lors
P reserva tives
D irec tly A d d ed
C lean in g C h em ica ls
P es tic id es
H eavy M eta ls
A n tib io tics
In d irec tly A d d ed F ood A lle rg en s
S eafood Toxin s
P lan t toxin s
F u n g a l Toxin s
N atu ra lly O ccu rin g
Chem ical
FOOD SAFETY HAZARDS
Foodborne Infections Result when pathogens grow in intestines after a person eats food contaminated by them
Foodborne Intoxications Result from eating food containing poisonous toxins
Foodborne Toxin-Mediated Infections Result from toxins produced by pathogens growing in the intestines
Salmonellosis Shigellosis Listeriosis Staphyloccocal food poisoning Clostridium perfringens Enteritis
Major Foodborne Illnesses Caused by Bacteria
Bacillus cereus gastroenteritis Botulism Campylobacteriosis E. coli O157:H7 EHEC Vibrio gastroenteritis Yersiniosis
Figure 21.2 Egg sizes
Egg Grades
SalmonellosisType of Illness: Infection, possibly toxin-mediated
ListeriosisType of Illness: Infection
Staphylococcal Food PoisoningType of Illness: Intoxication
Clostridium perfringensType of Illness: Toxin-mediated infection
BotulismType of Illness: Intoxication
E. coli O157:H7 EHECType of Illness: Toxin-mediated infection
Can’t reproduce outside a living cell Usually contaminate food through poor personal hygiene May survive freezing and cooking Contaminate food and water
Hepatitis A Norwalk Virus Gastroenteritis Rotavirus Gastroenteritis
Major Foodborne Illnesses Caused by Viruses
Hepatitis AType of Illness: Infection
Norwalk Virus GastroenteritisType of Illness: Infection
Parasites Need to live in or on a host organism in order to survive
Host
Person Animal Plant
Freeze properly Cook to proper temperatures Avoid cross-contamination Use sanitary water supplies Wash hands properly
Keys to Prevention
Trichinosis Anisakiasis Giardiasis Toxoplasmosis Intestinal Cryptosporidiosis Cyclosporiasis
Major Foodborne Illnesses Caused by Parasites
Trichinosis
also called trichinellosis, or trichiniasis, is a parasitic disease caused by eating
raw or undercooked pork or wild game infected with the larvae of a species of roundworm Trichinella spiralis, commonly called the trichina worm.
Major Foodborne Illnesses Caused by Parasites
Anisakiasis
is a genus of parasitic nematodes, which have a life cycle involving fish and marine mammals.
Major Foodborne Illnesses Caused by Parasites
Gardiasis
(discovered by DR James de Silva) in humans is a diarrheal infection of the small intestine by a single-celled organism called Giardia lamblia. Giardiasis occurs worldwide with a prevalence of 20–30% in developing countries.
Major Foodborne Illnesses Caused by Parasites
Giardia lamblia cell
Toxoplasmosis
is a parasitic disease caused by the protozoan Toxoplasma gondii. Up to one third of the world's human population is estimated to carry a Toxoplasma infection. Ingestion of raw or partly cooked meat, especially pork, lamb, or venison containing Toxoplasma cysts.
Major Foodborne Illnesses Caused by Parasites
Protozoan T. gondii
Intestinal Cryptosporidiosis also known as crypto, is a parasitic disease caused by Cryptosporidium, a protozoan parasite. It affects the intestines of mammals and is typically an acute short-term infection. It is spread through the fecal-oral route, often through contaminated water
Major Foodborne Illnesses Caused by Parasites
Cryptosporidium muris
Cyclosporiasisis an infection with the protozoan Cyclospora cayetanensis, a pathogen transmitted by feces or feces-contaminated fresh produce and water. Outbreaks have been reported due to contaminated raspberries. It is not spread from person to person.
It can be a cause of diarrhea for travelers.
Major Foodborne Illnesses Caused by Parasites
Cyclospora cayetanensis
TrichinosisType of Illness: Infection
AnisakiasisType of Illness: Infection
Fungi
Molds Yeasts Mushrooms
Fungi Commonly cause food spoilage, not illness
Foodborne Infections Result when pathogens grow in intestines after a person eats food contaminated by them
Foodborne Intoxications Result from eating food containing poisonous toxins
Foodborne Toxin-Mediated Infections Result from toxins produced by pathogens growing in the intestines
Prepare an outline for a discussion of the four types of microorganisms. Include examples of what microorganisms need to survive and grow. Highlight the conditions managers have the most influence over.
Challenge participants to create a list of foods high in acid and another list of highly alkaline foods. Reward the participant who comes up with the most examples and have him or her share the list with the class.
Create a blank handout of a thermometer and have participants indicate the space for the temperature danger zone.