Download lecture 15

Food Safety & Technology
HLTH-120N Nutrition
Lecture 15A
“Food Poisoning”
Objectives
• Differentiate between food infection & intoxication
• Identify several organisms involved in food-borne
illness
• Describe strategies for preventing food-borne illness
• Explain the purpose of and risks associated with
canning, preservatives, and irradiation.
• Describe the risks & benefits of GMO’s & pesticides
• Understand the GRAS list & food additive safety
• Describe how pollutants build up in foods
• Understand the labeling system for organic food
Food-Borne Illness
• Symptom or illness from food or water
that contains an infectious agent or toxic
substance
• 76 million cases each year
▫ Over half unknown or unreported
Who is at high risk?
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•
•
•
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Food Safety & Quality Regulation
• USDA
▫ Meat, poultry & eggs
• FDA
▫ All food products except meat, poultry & eggs
▫ Enforces pesticide use
• CDC
▫ Aids in food safety education of the public
▫ Tracks the cause of food-borne illnesses
• EPA
▫ Regulates pesticide use & establishes water quality
Causes of food-borne illness
• Food infection
▫ consumption of food containing
living microorganisms (bacteria & viruses)
• Food intoxication
▫ Consumption of food in which
microbes have secreted poisonous
substances called toxins
Bacteria
Incubation
Symptoms
Foods
Campylobacter 1-7 days
Jejuni
Fever, headache, muscle Raw meat, poultry,
pain, diarrhea
fish; raw milk;
water
Salmonella
12-24 hrs
Diarrhea, ab pain, chills, Undercooked eggs,
vomiting
meat, raw dairy,
poultry, f/v
E. Coli
2-4 days
Diarrhea, ab cramps,
Water, raw milk,
nausea, kidney infection beef, uncooked f/v
C. Botulinum
12-36 hours
n/v, diarrhea, fatigue,
Canned food, meat,
muscle paralysis, double fish, honey
vision, dry mouth
Staphylococcus 1-6 hours
Severe n/v, diarrhea,
cramping
Custard, cream
filled baked goods,
cream sauces,
dressing, gravy
Microbes
• Helminths
▫
• Parasite:
▫ benefits from and harms its host
• Fungi:
▫ plant-like & spore-forming
• Prion:
▫ self-replicating protein particle
 causes mad cow disease (bovine spongiform encephalopathy (BSE) )
Microbes release toxins
• Neurotoxins
▫ damage the
system, cause paralysis
▫ C. Botulinum: found in bulging cans, foods improperly
canned at home, raw honey
• Enterotoxins
▫ target the
system,
causing severe diarrhea and vomiting
• Mycotoxins
▫ secreted by fungi
Toxins without microbes
• Toxin present in food without microorganism
•
• Marine Toxins
• Greening in potatoes: solanine
Defense against the organism
• Antimicrobial enzymes in
•
.
in the stomach
•
• Activated immune system
• Diagnose: obtain and culture a specimen
• Stay hydrated!
How Microbes multiply
• In the “danger zone”
▫
to
• Humidity
• Oxygen
• Acidity
.
Preventing Illness at home
• Clean: Wash hands & surfaces often
• Separate foods to
• Chill foods to prevent growth
• Cook foods to proper temperature
Food Storage & preparation
• Store foods in small containers, to reach
degrees within
hours
▫ Eat within 4-5 days
• How should you thaw foods?
• Traveling
▫ use bottled water and avoid ice & raw foods
Reheating
foods will kill
__________
but not toxins
Modern Preservation
• Industrial Canning
• Pasteurization
• Packaging techniques
• Preservatives
▫ (antioxidants, mold inhibitors, sulfites,
nitrites, nitrates)
• Irradiation
• Genetic Modification
Canning
• Food is sorted & washed
• Food is then blanched
• Cans are filled & heated
• Air siphoned out of cans & sealing
• Heated & Cooled
Pasteurization
• Invented by Louis Pasteur to destroy
microorganisms in spoiled wine
• Involves quick heating
▫ Usually to 160 degrees for 15 seconds
• Which products are pasteurized?
Packaging Techniques
• Aseptic
▫ Sterilized in flash heat & cool
▫ Placed in sterile container
• Modified Atmosphere
▫ Oxygen in package replaced with inert gas
• High-pressure
▫ Bacteria inactivated with extreme pressure
Preservatives
•
• Antioxidants
• Mold Inhibitors
• Sulfites
• Nitrates/Nitrites
Food Additives
• Flavoring agents
▫ essential oils, extracts, or spices
• Flavor enhancers
▫ Examples: maltol and MSG
• Food colorings
▫ Natural colorings
▫ Synthetic:
 Red #2, yellow #5, etc.
 Can cause allergic reactions in some people;
use must be indicated on the product packaging
Food Additives
• Vitamins and other nutrients:
▫ Vitamins E and C (ascorbic acid): antioxidant
▫ Iodine (
) helps to decrease ________
▫ Vitamin D and calcium for bone health
▫ Folate (breads, cereals) to decrease neural tube
defects during fetal development
Food Additives
• Texturizers, stabilizers, and emulsifiers
• Thickening agents
▫ Pectin, carrageenan, etc
• Humectants maintain correct moisture levels
▫ Sorbitol, propylene glycol
• Desiccants prevent moisture absorption
Food Additive Safety
• Delaney Clause:
▫ “No additive may be permitted in any amount if
tests show it produces cancer when fed to man or
animals or by other appropriate tests”
• GRAS list
▫ Safe by either research or consensus
• Adverse Reaction Monitoring System
▫ Sulfites
Food Residues
• Chemicals that remain in foods despite cleaning
and processing
• Persistent organic pollutants (POPs):
chemicals released into the atmosphere
• Mercury and lead: neurotoxins
• Industrial pollutants: PCB’s
Irradiation
• Eliminates bacteria & fungus in meats & poultry
• Exposes food to gamma rays from radioactive
metals
• Approved by 50 countries & promoted by WHO
• Can slightly change taste & smell of products
▫ Damages vitamins A, E, K and thiamin
• Irradiated foods must
be marked with
this internationally
recognized symbol
• “treated with radiation,
do not irradiate again”
must be stated
Genetic Modification
• Selective Breeding
• Recombinant DNA Technology
▫ DNA segment w/ desirable trait isolated
▫ Copies of segment spliced into traditional plant
• GMO:
▫ DNA of food has been altered
▫ Purpose: resist herbicides & pesticides
▫ Benefits & harm greatly debated
Pesticides
• Protect against weeds, insects, fungi and increase
crop yields
• Insecticides, herbicides, fungicides
• Can be natural or synthetic
• Remain on foods
• Who is especially sensitive?
• EPA controls use of pesticides
Growth Hormones
• Recombinant bovine growth hormone (rBGH):
genetically engineered & given to cows
▫ Increases muscle mass; decreases fat
▫ Increases milk output
▫ Causes mastitis in cows, resulting in
__________________
▫ methicillin-resistant Staphylococcus aureus
(MRSA) develops
Organic Foods
• Conventional non-organic pesticides,
insecticides, and herbicides are restricted
• Livestock must be raised without the use of
antibiotics or growth hormones
• Cannot be genetically modified
• Raised & harvested in an organic environment
as approved and certified by the USDA