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Food Safety & Toxicology
What is Food Safety?
Food Safety is making a food safe to eat
and free of disease causing agents such
as:
 Too many infectious agents
 Toxic chemicals
 Foreign objects
What is Food Quality?
Food Quality is making a food desirable to
eat with regards to good taste, color,
and texture; bad food quality can be
judged by:
 Bad color
 Wrong texture
 Smells bad
Unacceptable Foods
Poor Quality
bad color
wrong texture
smells bad
Unsafe
too many bacteria
toxic chemicals
foreign objects
Hazard

A biological, chemical or physical agent
that is reasonably likely to cause illness
or injury in the absence of its control
What are the Type of Food Hazards?
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Biological: bacteria, viruses, parasites
Chemical: heavy metals, natural toxins,
sanitizers, pesticides, antibiotics
Physical: bone, rocks, metal
A. Biological Hazards

Microorganisms
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Yeast
Mold
Bacteria
Viruses
Protozoa
Parasitic worms
How Do Foods Become Contaminated?
What do microorganisms need?

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Food
Water
Proper temperature
Air, no air, minimal air
Bacterial Hazards

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Food infection and food intoxication
Sporeforming and nonsporeforming
bacteria
Sporeforming Bacteria (Pathogens)

Clostridium botulinum
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Proteolytic
Nonproteolytic
Clostridium perfringens
Bacillus cereus
Nonsporeforming Bacteria
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Brucella abortis, B. suis
Campylobacter spp.
Pathogenic Escherichia coli (e.g., E. coli O157:H7)
Listeria monocytogenes
Salmonella spp. (e.g., S. typhimurium, S. enteriditis)
Shigella spp. (e.g., S. dysinteriae)
Pathogenic Staphylococcus aureus (e.g., coagulase positive S.
aureus)
Streptococcus pyogenes
Vibrio spp. (e.g., V. cholerae, V. parahaemolyticus, V. vulnificus,)
Yersinia enterocolitica
In meat and poultry:
 Salmonella bacteria (poultry and eggs)
 Trichinella spiralis parasite (pork)
On fruits and vegetables:
 E. coli bacteria (apple juice)
 Cyclospora parasite (raspberries)
 Hepatitis A virus (strawberries)
Viral Hazards
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Very small particles that cannot be seen with a light
microscope
Do not need food, water or air to survive
Do not cause spoilage
Infect living cells and are species specific
Reproduce inside the host cell
Survive in human intestines, water or food for months
Transmission usually by fecal-oral route and related to
poor personnel hygiene
Control of Viruses

No Virus survives heating at 140°F (60oC) for
30 minutes
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Inactivated by boiling at 212°F
Hand sanitizers/antiseptics ineffective
Important controls
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No bare hand contact with ready-to-eat food
Proper handwashing
Not preparing food when ill
Parasites in Foods
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Parasites are organisms that need a host to survive
Thousands of kinds exist worldwide, but only about 100
types are known to infect people through food
contamination
Two types of concern from food or water:

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Parasitic worms [e.g., roundworms (nematodes), tapeworms
(cestodes), flukes (trematodes)]
Protozoa
Role of fecal material in transmission of parasites
Parasitic Protozoa and Worms

Roundworms (nematodes)
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Tapeworms (cestodes)
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Anisakis simplex
Ascaris lumbricoides
Pseudoterranova dicepiens
Trichinella spiralis
Diphyllobothrium latum
Taenia solium, T. saginata
Flukes (trematodes)
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Protozoa
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Cryptosporidium parvum
Entamoeba histolytica
Giardia lamblia
Foodborne Illness
Percentage of Foodborne Illness
Attributable to Known Pathogens
Bacteria
30%
Protozoa
3%
Mead et al., 1999
Viruses
67%
What is a Foodborne Illness?
Foodborne illnesses are caused by agents that enter the
body through the ingestion of food.
 Every person is at risk of foodborne illness.
 May be serious for very young, very old, people with long
term illness
 Reaction may occur in a few hours or up to several days
after exposure
Symptoms
 Abdominal cramps, headache, vomiting, diarrhea (may be
bloody), fever, death
What is the Impact of Foodborne Illness?
In the US (Centres for Disease Control and
Prevention) annually:
 76 million cases of foodborne diseases
 325,000 hospitalization
 5,000 deaths
In China (1994) Salmonella Outbreak :
 estimated 224,000 persons
Why is Foodborne Illness increasing in the
US?
Food:
 Preference for “rare” meats
 Increase shelf life of products which allow for bacterial
growth
 Increase consumption of imported ready-to-eat foods
How can you prevent Biological Hazard
to Foods?
Prevention of microbes growing

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Holding at low temperatures (<40oF)
Cooling from 140o-40oF quickly
Cooking helps to kill microbes
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>165oF(73o C) for poultry and eggs
>155oF (68o C) for ground beef
>160oF (71o C) for pork
Food from Unapproved Source
Food from Unapproved Source
Food from Unapproved Source
Unapproved Cheese Product
B. Chemical Hazards in Food
Chemical hazard: a toxic substance that is
produced naturally added intentionally or unintentionally
 Naturally-occurring:
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Added intentionally:
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Natural toxins (aflatoxins)
Antibiotics, preservatives
Added non-intentionally:

Cleaning agents, Pesticide residues
Intentionally Added Chemicals Food Additives

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Preservatives (e.g., nitrite and sulfiting
agents)
Nutritional additives (e.g., niacin, vitamin A)
Color additives (e.g., FD&C Yellow No. 5)
Unintentionally or Incidentally Added
Chemicals
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Agricultural chemicals
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Toxic elements and compounds
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e.g., pesticides, fungicides, herbicides, fertilizers,
antibiotics and growth hormones
e.g., lead, zinc, arsenic, mercury, cyanide
Secondary direct and indirect

e.g., lubricants, cleaning compounds, sanitizers, paint
Mercury
Polluting with HG
MeHg kid
C. Physical Hazards In Food
• Physical hazard: a hard
foreign object that can
cause illness or injury
Examples: plastic,
bones, wood, glass,
metal fragments
 Poor handling
procedures in the food
flow
Hazard Analysis Critical Control Point
(HACCP)
What is Hazard Analysis Critical
Control Point (HACCP)?
The purpose of HACCP is to help ensure the
production of safe food
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The goal of HACCP is to prevent and/or minimize
risks associated with biological, chemical, and
physical hazards to acceptable levels
It is based on PREVENTION rather than detection
of hazards
Pioneered in the 1960’s: first used for the space
program (Pillsbury & NASA)
What are the Steps involved in
HACCP?
1. Identify hazards
2. Determine Critical Control Points (CCPs)
3. Determine safety limits for CCPs
4. Monitor CCPs
5. Corrective action
6. Record data
7. Verify that the system is working
Good Practices in Food Chain
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Good
Good
safe)
Good
Good
Good
Good
Agricultural Practices (pesticide use)
Catering Practices (ensure food served is
Hygiene Practices
Manufacturing Practices
Storage Practices
Transport Practices
Shared responsibility
Government
Consumer
Industry
Food legislation/
enforcement
Educated public
Good practices by
producers &
distributors
Consumer education
Safe food
Appropriate process &
practice in home technology
Safe Eating …….