Lesson 10 Flashcards
what is risk ?
a measure of the probability and severity of harm under DEFINED CONDITIONS OF EXPOSURE
what is the risk of dying from cancer in canada ?
30%
what is the risk of dying from heart disease in canada ?
19.7%
what does risk depend on ?
behavior
what are 4 diseases in which risk of death depends on diet ?
cancer
heart disease
stroke
diabetes
what is the rate of risk of acquiring a foodborne illness in Canada per year ?
1/8 people so 12.5%
what is chronic sequelae ?
chronic complications following an acute illness
what is a risk in foodborne illnesses in 2-3% of cases ?
chronic sequelae which may be more detrimental than the acute disease
what are pathogens ?
microorganisms capable of causing disease
are all bacteria pathogenic ?
no
what are 5 classes of people that are more susceptible to pathogens ?
very young very old pregnant women malnourished compromised immune systems
what are foodborne illnesses ?
illness transmitted to human beings through food and water, caused by an infectious agent (foodborne infection) or a poisonous substance (food intoxication, so by an agent’s toxic secretions)
what are the two ways foodborne illnesses are transmitted to humans ?
through food and water
foodborne infections are caused by eating foods contaminated by _____
live pathogens
what are 4 symptoms of foodborne infections ?
abdominal cramps
fever
vomiting
diarrhea
due to the pathogens proliferating in the GI tissue
what is food intoxication caused by ?
eating foods containing natural toxins produced by pathogens (meaning the pathogens do not necessarily need to be in there)
enterotoxins (infect GI) or neurotoxins (infect nervous system)
how long do you get sick once contaminated food is consumed ? what does it depend on
onset of symptoms depends on the time it takes for the pathogens to grow and proliferate in the small intestines
how long is the onset of symptoms for food intoxication ?
within a few hours
what are 4 classes of pathogens in food ?
foodborne bacterial pathogens
foodborne viral pathogens
bacterial toxin producers
other microorganism producing toxins
what are 4 exampels of foodborne bacterial pathogens ?
campylobacter jejuni
salmonella
E. coli
listeria
what is an example of a foodborne viral pathogen ?
Norwalk virus
what are 2 examples of bacterial toxin producers ?
staph aureus
clostridium botulinum
what are 2 examples of other microorganisms producing toxins ?
fungi: aflatoxin
algae: marine toxins
how does sex happen for bacteria ? what is it called ?
uncoupled sexual production
pili extend to other cells, permitting exchange of genetic information, permitting an exchange of genes from a donor cell to a recipient cell
explain bacterial reproduction
there is none. two cells come together, modify, and then go apart.
when does bacterial uncoupled sexual production become a problem ?
when bacteria exchange genes for antibiotic resistance (esp inside of livestock)
what are 2 ways to contaminate food with campylobacter jejuni ?
eating undercooked meat
improperly handling poultry
what is a dangerous practice when it comes to rinsing raw poultry? what does it put at risk for ?
washing or rinsing raw poultry before cooking it is potentially unsafe bc of the splashing of contaminated water, which may lead to the transfer of pathogens to other foods and kitchen surfaces
what 3 diseases are related to campylobacter jejuni ?
Guillain-Barre syndrome (neuromuscular paralysis)
reactive arthritis
IBS
which neurodegenerative disease is linked to campylobacter jejuni and what is the association ?
Guillain-Barre
1 case for GBS for every 1000 of campylobacteriosis
what percentage of people with GBS have evidence of recent campylobacter infection ?
40%
can patties be cooked raw ?
no
why can’t patties be cooked raw, but steaks can ?
because steaks : pathogens stay on the surface, so searing it is fine
but for patties, the pathogens are mixed throughout the grinding process
what are two things that happen in patties during the grinding process ?
increase the surface area for protein-rich tissue for microbes to grow
+ supplies oxygen for microbes to grow and multiply
what is a main cause of E.coli infections ?
mechanically tenderized meat (incising the surface of meat to tenderize it)
what is a way of reducing risk of E. coli
indicating when a meat has been mechanically tenderized
where is listeria found ?
in soil and water
what are two ways listeria adapted to increase its pathogenicity?
forms biofilm on surfaces
can grow and multiply in refrigerator
which pathogen can find its way into packaged food ?
listeria
what is biofilm
sticky, slimy film that adheres on surfaces
what is listeria killed by ?
pasteurization and cooking
what happened in the listeriosis outbreak in Ontario ?
contaminated after factory cooking lunch meats and hot dogs
why can listeria infection risk increase with using precut lettuce ?
cutting liberates nutrients previously confined to insides of plant cells, and these released nutrients become food for pathogens to grow
+ precut lettuce hard to wash properly
what are 3 words for the Norwalk virus ?
norovirus
stomach flu
winter vomiting disease
what are 4 symptoms of the Norwalk virus ?
vomiting
diarrhea
abdominal pain
body aches
what is the contagiousness and duration of Norwalk virus symptoms ?
very contagious, but short lived symptoms (less than 2 days)
what are 3 ways to transmit the Norwalk virus ?
contaminated food
contaminated water
human contact
what areas of the body is staph aureus commonly found (2)
hands and nose
explain the mechanism of action of the staph aureus
cooked food contaminated w staph aureus when served by a person with unwashed hands
bacteria multiply and produce a toxin
when leftover food is reheated, it destroys the bacteria but not the toxin
how long does it take for the staph aureus symptoms to occur ? what are they
nausea, vomiting, stomach pain 1-6 hours after consumption
what does clostridium botulinum produce ?
botulinum
what is the most poisonous substance known to man ?
botulinum
where is botulinum found in nature ?
in spores in plants and in soil
which toxin doesn’t need oxygen to multiply ?
botulinum
what is the most common cause of intoxication from botulinum?
home canned foods and homemade garlic and oils stored at room temperature
what kind of toxins do fungi produce ?
mycotoxins
what is aflatoxin ?
a type of mycotoxin, produced by fungi in mouldy crops
what legume contains trace amounts of aflatoxin ?
peanuts
aflatoxin may cause which disease ?
liver cancer
what regions in the world are especially vulnerable to liver cancer due to aflatoxin ?
africa (40%)
east asia
western pacific
(north america and europe 0%)
what is the most well known algae toxin ?
algae which produce toxic red tides
how can climate change increase toxic red tides ?
favoring the growing conditions
what is a pesticide ?
any chemical used to control unwanted insects, fungi, weeds
where do 99% of deaths due to pesticides occur ?
in developing countries
what are the three modes of entry of pesticides ?
inhalation
dermal contact
ingestion
who is at most risk of dying from pesticides ?
those who apply it
what is the reference dose ?
a function of the dose at which no effects from pesticides are observed, and then divided to account for more vulnerable people and amount of evidence
what is the risk of pesticides dependent on ?
where you live
what is the main factor of food preservation techniques ?
temperature (heat or cold)
what is irradiation ?
use of low dose radiation to kill pathogens on food
irradiation is permitted by Health Canada on which 3 foods ?
spices
onions and potatoes
wheat flour
what international symbol do irradiated foods have ?
radura
what does irradiation prevent on onions and potatoes ?
premature sprouting
is irradiation really related to cancer ?
no ! most potential human hazards are false alarms leading to overregulation
is irradiation safe ?
yes
what are nitrites ?
an additive used to preserve lunch meats and sausages
are nitrites safe ?
they are considered a necessary evil (risk-risk tradeoff): they are carcinogenic but prevent botulism
