Lesson 2
What Are the Hazards to
Safe Food?
1
Food Hazard
Anything that interferes with safe food
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3 Categories of Food Hazards
 Physical
 Chemical
 Biological
3
Physical Hazards
Anything foreign to food
 Dust
 Dirt
 Hair
 Metal shavings
 Broken glass
 Foreign objects
4
dust
hair
Chemical Hazards
 Cleaning solutions
 Pesticides
 Toxic metals
5
Biological Hazards =
Pathogenic Microorganisms
Type of Microorganism
Bacteria
Viruses
Parasites
Fungi
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Example
E. coli 0157:H7
Norwalk-like virus
Giardia
Aspergillus
Biological Hazards
 Cause more foodborne illness (FBI) than
physical or chemical hazards
 Are more difficult to control than physical or
chemical hazards
 The rest of this lesson will discuss various
characteristics of microorganisms
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Activity: Is It a Physical, Chemical,
or Biological Food Hazard?
Food Hazard
An assistant cook has an open
sore on her hand.
Tomato soup is stored in a copper
bowl.
A glass is used to scoop ice.
After cutting raw chicken, the
food service worker uses the
same knife to slice fruit.
The counter cleaner is stored next
to the flour on an overhead shelf.
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Physical Chemical Biological
X
X
X
X
X
Microorganisms Are Microscopic!
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From Idaho Food Safety and Sanitation Manual, p. 1.1
Microbes in Food
 Bacteria and fungi can grow in
food.
 Bacteria, yeast, and molds can
be “good guys” or “bad guys”
or harmless.
 Viruses and parasites do not
grow in foods.
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Yeast Cell = good
BAC = bad
Use FAT TOM to remember.
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Bacterial Growth
FAT TOM
Food
Acidity
Temperature
Time
Oxygen
Moisture
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Bacterial Growth
FAT TOM
 Food or nutrients—
especially foods
high in protein
favor bacterial
growth
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Bacterial Growth
FAT TOM
 Food
 Acidity - mild to low acidity favors bacterial
growth (pH ~ 4.6 to 7)
Acid foods help control microbe growth.
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Acidity
pH scale = 1 to 14
pH of some foods
4.6
2
15
3
4
5
6
7
8
Bacterial Growth
FAT TOM
 Food
 Acidity - low
 Temperature –
Ideal
temperature is
90-110ºF.
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Bacterial
Growth
135°F
The “Danger Zone”
is 41º to 135ºF.
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41°F
Bacterial Growth
FAT TOM
 Food
 Acidity
 Temperature
 Time – no
more than 4
hours in the
Danger Zone
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Activity: Calculate
Bacterial Growth
Time
0
30 min
1 hour
2 hours
4 hours
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Number of Bacteria
5
20
80
1,280
327,680
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21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
Bacterial Growth
FAT TOM
 Food
 Acidity
 Temperature
 Time
 Oxygen requirements
vary
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Bacterial Growth
FAT TOM
 Food
 Acidity
 Temperature
 Time
 Oxygen
 Moisture Water activity
of 0.85 or
higher
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Water Activity
0.85
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
raw
meat
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Bacterial Growth Is Favored By
FAT TOM
 Food - especially protein foods
 Acidity - mild to low acidity
 Temperature - 41º to 135ºF is The Danger
Zone
 Time - more than 4 hours in The Danger Zone
 Oxygen - varies for different types of bacteria
 Moisture - water activity of 0.85 or higher
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Vegetative Cells vs. Spores
 Vegetative cell = destroyed by
heat (most by a temperature of
165°F)
 Spore = more resistant to heat
(requires 240°F to destroy)
Spores
Vegetative cells
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Potentially Hazardous Food
 Foods that support the rapid growth of
harmful bacteria
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Potentially Hazardous Foods
Generally
 High protein
 Low acid
 High moisture
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Song Activity: Stayin’Alive
Well you can tell by the way I
choose my food
I’m a worried guy, in a cautious
mood
Food safety scares, they’re
everywhere
And they’re telling me I should
beware
There’s pesticides, Mad Cow
Disease
Sure don’t put my mind at ease
Biotech, and MSG
Messin’ with my sanity
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Don’t want hepatitis or that
gastroenteritis
I’m just stayin’ alive, stayin’ alive
Scrubbin’ off my veggies and I’m
heatin’ all my burgers
Up to one-fifty-five, for fifteen
seconds
Ah, ha, ha, ha, stayin’ alive, stayin’
alive
Ah, ha, ha, ha, stayin’ alive
Stayin’ Alive
Now when I was young I wouldn’t
hesitate
To chow right down, clean off my
plate
With oysters raw and burgers rare
I enjoyed my food without a care
But now I hear, it’s not OK
I might not live another day
Believin’ Oprah, Meryl Streep
Soon I might be six feet deep
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Don’t want hepatitis or that
gastroenteritis
I’m just stayin’ alive, stayin’ alive
Scrubbin’ off my veggies and I’m
heatin’ all my burgers
Up to one-fifty-five, for fifteen
seconds
Ah, ha, ha, ha, stayin’ alive, stayin’
alive
Ah, ha, ha, ha, stayin’ alive
Stayin’ Alive
I’m scared senseless. Somebody
help me
Somebody help me, yeah
I’m scared senseless. Somebody
help me
I’m stayin’ alive
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Well you can tell by the way I
choose my food
I’m a worried guy, in a cautious
mood
Food safety scares, they’re
everywhere
And they’re telling me I should
beware
There’s pesticides, Mad Cow
Disease
Sure don’t put my mind at ease
Biotech, and MSG
Messin’ with my sanity
Stayin’ Alive
Don’t want hepatitis or that
gastroenteritis
I’m just stayin’ alive, stayin’ alive
Scrubbin’ off my veggies and I’m
heatin’ all my burgers
Up to one-fifty-five, for fifteen
seconds
Ah, ha, ha, ha, stayin’ alive, stayin’
alive
Ah, ha, ha, ha, stayin’ alive
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I’m scared senseless. Somebody
help me
Somebody help me, yeah
I’m scared senseless. Somebody
help me
I’m stayin’ alive
Potentially Hazardous Foods
 Any food of animal origin–All
meats (red meat, poultry, fish,
shellfish, crustaceans, etc.) eggs,
milk, and dairy products.
 Any food of plant origin that has
been heat treated.
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Potentially Hazardous Foods
continued
 Raw seed sprouts
 Cut melons
 Garlic-in-oil mixtures
(not modified to
prevent pathogen
growth)
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Activity: Which Foods Are
Potentially Hazardous?
 Hamburger patties,
raw
 Bananas
 Cut cantaloupe
 Bread
 Yogurt
 Pizza
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 Can of soup,
unopened
 Dry pasta
 Cooked pasta
 Shell eggs
 Baked potato
 Alfalfa sprouts
Understanding Check!
Each picture
represents what
category of
food hazard?
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Understanding Check!
This picture
represents “what”
bacteria growth
condition?
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Understanding Check!
This picture represents “what” bacteria growth
condition?
4.6
2
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3
4
5
6
7
8
Understanding Check!
This picture
represents “what”
bacteria growth
condition?
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Understanding Check!
This picture
represents “what”
bacteria growth
condition?
55
Understanding Check!
 These words represents “what” bacteria
growth condition?
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Understanding Check!
This picture
represents “what”
bacteria growth
condition?
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Understanding Check!
What are the characteristics of PHF?
Is this a potentially hazardous
food? Why or why not?
Is this a potentially hazardous
food? Why or why not?
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