The science of nutrition 4th edition thompson manore vaughan chapter 15

Chapter 15 Lecture

Chapter 15:
Food Safety and
Technology:
Protecting Our
Food

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Foodborne Illness
• Symptom or disorder from food or water
contaminated with pathogenic microorganisms,
it's toxic secretions, or a toxic chemical
• Commonly called food poisoning
• According to CDC, 48 million Americans
experience foodborne illness each year
• Major public health concern in recent years

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Body Responses to Contaminants
• Antimicrobial enzymes in saliva and hydrochloric
acid in the stomach kill some contaminants
• Vomiting and diarrhea effectively expel offenders
• White blood cells activate immune response

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People at Risk
• Developing fetuses, infants, and young children,
whose immune systems are still immature
• Pregnant women
• The very old and the frail elderly
• People with chronic illnesses (e.g., diabetes)
• People with acquired immunodeficiency
syndrome (AIDS)
• People who are receiving immune-systemsuppressing drugs (e.g., transplant recipients
and cancer patients)
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Foodborne Illness Challenges
• Substantial and increasing portion of U.S. food
supply is imported
• Regulation and oversight in country of origin
may be inadequate
• Produce is responsible for greatest percentage
of foodborne illness, but meat and poultry are
responsible for the greatest percentage of
deaths
• U.S. federal oversight of food safety is
fragmented (USDA, FDA, CDC, EPA)

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Causes of Foodborne Illness
• Food intoxications: consuming food in which
microbes have secreted harmful substances
called toxins
• Naturally occurring toxins (plant and marine)
• Chemical residues
• Viruses
• Bacteria
• Parasites
• Fungi

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Microorganisms Contaminate Food
• Bacteria and viruses are the most common
microorganisms causing foodborne illnesses
• Viruses: Norovirus and Hepatitis A virus (HAV)
• Norovirus is most common cause of
foodborne illness in U.S.
• Most common bacterial contaminant:
• Salmonella: second leading cause of
foodborne illness, causes the most deaths

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• Norovirus.
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• The salmonella bacterium.
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Microorganisms Contaminate Food (cont.)
• Helminths (worms), include tapeworms, flukes,
roundworms
• Parasites: benefit from and harm the host
(Giardia)
• Fungi: plant-like spore-forming organisms
(yeasts and molds)
• Prions: self-replicating protein particles that
cause mad cow disease (bovine spongiform
encephalopathy [BSE ])

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• Tapeworm.
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• Molds rarely cause foodborne illness because
they make food unappetizing.
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Microorganisms Release Toxins
• Bacteria and fungi secrete toxins that bind to
cells and cause a variety of symptoms
• Can be very serious or even deadly
• Include bacterial, fungal, and plant toxins, and
toxic algae

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Microorganisms Release Toxins (cont.)
• Neurotoxins damage the nervous system, cause
paralysis
• Clostridium botulinum: bacterium found in
bulging cans, foods improperly canned at
home, raw honey; produces deadly toxin
• Enterotoxins target the gastrointestinal system,
cause severe diarrhea and vomiting
• Staphylococcus aureus is the most common
• Mycotoxins are secreted by fungi

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• This fly agaric mushroom contains dangerous
fungal toxins.
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Toxic Algae
• Red tides along shorelines caused by toxic
algae.
• Shellfish beds are closed during red tides to
protect the public
• Ciguatoxins: marine toxins produced by algae

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Plant Toxins
• Solanine, a plant toxin found in potatoes, forms
during the greening process
• Highly toxic even in small amounts
• Green potatoes should be thrown away, never
consumed; always wash potatoes to expose
color
• Greening can be avoided by storing potatoes for
only short periods, in dark, cool places such as a
cupboard or paper bag

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Conditions for Multiplying Microrganisms

• Temperature: 40−140°F (4−60°C) is the "danger
zone"; warm temperatures where toxic
microorganisms in food thrive
• Humidity; moist foods
• Acidity; preferred pH ranges for microbes
• Oxygen content: food preservation techniques
that remove oxygen help fight microorganisms

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Preventing Foodborne Illness
• When preparing foods at home, be sure to:
1. Wash hands and kitchen surfaces often
2. Separate foods to prevent crosscontamination
3. Chill foods to prevent microbes from growing
4. Cook or heat foods thoroughly to their
proper temperature
5. Use precautions to prevent toxins from
forming; keep hot foods hot and cold foods
cold.
• Be aware when eating out.
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© 2017 Pearson Education, Inc.

© 2017 Pearson Education, Inc.