chapter 10: food safety Flashcards
risk
the probability of incurring harm
the probability that a substance or activity will cause harm under defined condition of exposure
–> it is dependent on behavior
In Canada, how many people get sick from domestically acquired food borne illnesses?
4 million people
1 in 8 people
12.5%
even if we are healthy, why do we worry about food borne illnesses?
because it can lead to chronic sequelae
–> a chronic disease
chronic sequelae
may occur in 2 to 3% of food borne cases?
secondary complication following an acute illness
microbes
organisms too small to be seen with the naked eye
bacteria
protists (algae)
fungi
pathogens
microbes capable of causing disease
some pathogens are more pathogenic than others
people more susceptible to pathogens
the very young
the very old
pregnant women
those with compromised immune systems
how are food borne illnesses transmitted to human beings?
through food and water
can be caused by an agent or an agent’s toxic secretions
caused by eating foods contaminated with live pathogens
food borne illness
illness transmitted to human beings through food and water
caused either by an infectious agent (food borne infection) or a poisonous substance (food intoxication)
commonly known as food poisoning
where food borne illness pathogens infect us?
basically, how are food borne infections started?
can infect the digest tract tissue and begin to proliferate
can find a hospitable environment for growth in the small intestine
symptoms of food borne illness
abdominal cramps
fever
vomiting
diarrhea
what are food intoxications caused by?
caused by eating foods containing natural toxins produced by pathogens
–> pathogens don’t need to be present for intoxication
–> the food has to be infused with toxin to be infected
the two types of natural toxins produced by pathogens
enterotoxins
neurotoxins
enterotoxins
affect the intestine
neurotoxins
affect the nervous system
how long would it take for us to get symptoms of a food borne infection? why?
can range from 1 day to several weeks
because the pathogens need to multiply in the small intestine first
how long would it take for us to get symptoms of a food intoxication?
it is much shorter (a few hours)
what are the pathogens types?
Foodborne Bacterial Pathogenes
Foodborne Viral Pathogenes
Bacterial Toxin Producers
Other Microorganism Producing Toxins
most common Foodborne Bacterial Pathogenes for our course
Campybacter jejuni
Salmonella
Escheria coli
Listeria
most common Foodborne Viral Pathogenes for our course
norwalk virus
–> causes diarrhea
most common Bacterial Toxin Producers for our course
staphylococcus aureus
clostridium botulinum
most common Other Microorganism Producing Toxins for our course
aflatoxin (fungal toxin)
marine toxins (algae)
how do bacteria have sex?
bacterial produce pili (an extension of cell membrane)
–> they reach other cells to exchange information and genes
–> no reproudction
–> two cells came together, and two cells slightly different went their own way
why do we have to concern outrselves with how bacteria have sex?
because bacteria living in livestock constantly exchange genes
–> even those for antibiotic resistance
–> food born pathogens resistant to antibiotic drugs can be created
Campybacter jejuni and Salmonella
reposnible for 1.8 million foodborne infections per year
how do we get Campybacter jejuni and Salmonella contamination
eating undercooked meat (especially chicken)
improperly handled chicken
Campybacter jejuni related diseases
Guillain Barre Syndrome (GBS)
reactive arthritis
Irritable Bowel Syndrome (IBS)
Guillain Barre Syndrome (GBS)
causes impariment of neurons leading to nearo muscular paralysis
1 case of GBS every 1000 cases of Campybacter jejuni
40% of those suffering have evidence of recent Campybacter jejuni infection
the truth Campybacter jejuni
can cause sever diarrhea
can cause abdominal pain
can cause heavy vomiting
most common ways to get Escherichia coli
improperly handling raw ground meat
eating undercooked ground meat
why do we need to thorughly cook a beef patty but not a steak
the bacterias are usually on a surface of a steak
in a beef patty, pathogens are mixed throughout the grinding process
–> more surface for microbes to grow and mutliply
Mechanically Tenderized Beef (MTB)
made by making incisions on the surface of an intact meat to break apart the muscle fibers in an effort to tenderize meat
why do MTBs have more bacteria
because of incisions made on the surface of an intact meat to break apart the muscle fibers in an effort to tenderize meat
–> openings allowing bacteria to penetrate the center
where is Listeria commonly found?
found in soil and water
what increases Listeria’s pathogenicity?
forming biofilms on surfaces
–> can find its way into packaged foods
unlike most pathogens, it can grow well and multiply in the refrigerator
how to kill Listeria
by pasteurization and cooking
where can we find listeria
on uncooked meat and even vegetation
why can buying pre cut lettuce increase our risk of listeria?
cutting liberates nutrients previously confined to the inside of plant cells
–> these released nutrients become food for pathogens to grow and multiply
precut lettuce is difficult to wash properly
the Norwalk virus
highly contagious
infections are short lived, lasting less than two days
different names for the Norwalk virus
Norovirus
Stomach flu
Winter Vomiting Disease
Norwalk virus symptoms
Vomiting
Diarrhea
Abdominal pain
Body Aches
how can the Norwalk virus be trasnmitted?
contaminated food
–> in particular, raw food
water
human to human contact
staphylococcus aureus
affects more than 1 million people per year
produces a toxin that makes us sick
commonly found on the surface of the skin (especially hands and nose)
how can food contract staphylococcus aureus
by being handled by someone with unwashed hands
just a single bacterial cell from unwashed hands can transfer to food
bacteria multiply if food is left out and produce toxin
food is reheated, killing the bacteria, but not the toxin
when do staphylococcus aureus symptoms appear and which are they?
after 1 to 6 hours
nausea
vomiting
stomach pain
where can clostridium botulinum spores be found?
in plants and soil
the most poisonous substance known to man
botulinum
what prevents clostridium botulinum spores from growing?
oxygen
a low PH environment
what do clostridium botulinum spores do once they grow in a hospitable environment?
what does this toxin do
they produce botulinum toxin
causes neuromuscular paralysis
what contains a diluted solution of botulinum toxin to make wrinkles dissapear?
botox
the most common causes of clostridium botulinum infection
home canned foods
homemade garlic
herb flavored oils stored at room temperature
the toxins produced by fungi
mycotoxins
alfotoxin
a type of mycotoxin (toxin produced by fungi)
produced by mouldy crops
has long been known to cause liver cancer
true or false
peanuts, corn, and other crops contain trace amounts of aflotoxin
truuuu
which goegrpahic location is ravaged by aflatoxin
Africa
40% of total aflatoxin
what is increasing the spread of mold on crops that causes aflatoxin?
climate change
marine toxins
produce metabolic by products that are released in the water
can accumulate in the tissues of the fish we eat
not fatal
climate change also favoring this
the most well known marine toxins
algae that produce toxic red tides
pesticide
any chemical used to control unwanted insects, weeds, or fungi
insecticides
pesticides that are used to kill herbivorous insects
herbicides
pesticides that are used on weeds that compete for resources with crop plants
fungicides
pesticides that are used to kill fungi that produce toxins
what do animals eat during times of low fruit production’?
what is the con of this?
they eat plant leaves
this has no advantage of dispersal for the plants, so they contain anti nutrients and alkaloids
the potential harm to humans that pesticides have
they are designed to kill
regular exposure to small amount of pesticides can initiate cancer
who is at biggest risk of whatever harm caused by pesticides?
those who apply pesticides
pesticides’ three modes of entry into the body
inhalation
dermal contact
ingestion
where do 99% of deaths caused by pesticides occur?
in developing countries
how is the pesticide reference dose calculated?
the dose at which no effects are observed
–> NAOEL
–> we divide by 10 to account for the most vulnerable people of the population
–> we divide again by ten if the only research data of effects came from testing on animals
–> then we divide by 10 if the amount of animal based evidence is limiting
basically, the risk is dependent on where we live
what does heating up food do to its shelf life?
it extends it
pasteurization
high heat for a brief period of time
kills some, but not all, microorganisms
heat processing of food that inactivates some, but not all, microorganisms in the food
not a sterilization process
bacteria that cause spoilage are still present
heat food preservation techniques
pasteurization
heat and pressure
cold food preservation techniques?
refrigeration and freezing
irradiation
a more aggressive measure of food preservation
use of low dose radiation to kill pathogens on food
sterilizing food by exposure to energy waves
similar to ultraviolet light and microwaves
sometimes called ionizing radiation
on which category of foods can we use irradiation?
spices
onions and potatoes
wheat flour
international symbol representing foods that have been irridated?
RADURA
is irradiation safe?
yes
it is 100% safe
irradiated food are safe to eat
nitrites
a type of additive use to preserve lunch meats and sausages
are a necessary evil
the Canadian agencies that ensure the safety of our food
- Health Canada
- Canadian Food Inspection Agency
- Agriculture and Agri-Food Canada
- Environmental Bureau of Agriculture and Agri-Food Canada
- Environment Canada
- WHO
