Food Toxicology Flashcards
(46 cards)
1
Q
Food toxicology is complicated
A
- not produced in a defined area, hard to have strict quality controls
- food is grown, harvested or caught
- food contains nutrients and non-nutrient substances
- different types of natural toxins that we can react to
2
Q
non-nutrients
A
-are found in both natural and heavily processed foods
3
Q
Food, Drug, Cosmetics Act
A
- presumes that food is safe if it is free of certain contaminants
- stuff can be added to food if it falls into Generally Recognized As Safe
4
Q
Generally Recognized as Safe
A
food colour additives
- with FD&C prefix
- natural in origin
5
Q
Nerve impulse transmission step 1
A
- Na+/K+ pumps move Na+ ions out of the nerve cell and K+ ions in
- charges of other molecules inside the axon block the positive charge of the K+ ions
- a resting state occurs with a greater positive charge on the outside of the cell largely due to the Na+ ions
6
Q
Nerve impulse transmission step 2
A
- neuron fires it lets the Na+ ion back in through Na+ channels
- a wave of depolarization that flows down the nerve axon
- Na+ channels quickly close and K+ channels open to allow the neuron to go back to its resting state
7
Q
Toxins from aquatic organisms
A
- produced by aquatic diatoms and dinoflagellates
- humans normally get poisoned by eating shellfish that have eaten these micro-organisms and absorb the toxin
8
Q
Paralytic Shellfish poisoning
A
- most common, severe, fatal
- dinoflagellates and cyanobacteria produced saxitoxins
- Symptoms: tingling, burning, numbness, drowsiness, incoherent speech, respiratory paralysis
9
Q
saxitoxins
A
- Na+ channel inhibitors leads to flaccid paralysis
- heat stable (don’t degrade from cooking)
10
Q
Neurotoxic Shellfish poisoning
A
- dinoflagellate
- produce brevotoxins
- Na+ channel blockers
- fish die off from this toxin
11
Q
Diarrheic shellfish poisoning
A
- algae make okadaic acids
- symptoms: mild diarrhea, nausea, vomiting, abdominal pain, chills, headache, fever
12
Q
Amnesic shellfish poisoning
A
- diatom makes domoic acid
- Symptoms: vomiting, diarrhea, confusion, memory loss, disorientation, seizure coma
- binds to excitatory amino acid receptors in neurons
- Ca++ influx and necrosis and apoptosis in nerve cells
- PEI outbreak, west coast shellfish closure
13
Q
west coast shellfish closure
A
- domoic acid
- large-scale ocean temperature anomaly
- big patch of warm water causing issues with weather and water quality
14
Q
Blue-green algae
A
- toxin-producing cyanobacteria
- high inflows of nutrients from agriculture
- blue-green algae can fix their own N
- When N is limited, can not out compete green algae and leads to harmful algal blooms
- microcystins-liver toxins
15
Q
mycrocystins
A
- inhibit activity of protein phosphates that remove phosphate groups from proteins that are necessary for their regulation
- in liver cause dysregulation of glucose metabolism
16
Q
scombroid poisoning
A
- tuna/mackerels
- fish containing high levels of free histidine
- spoilage bacteria back down free histidine into histamine
- Symptoms: immediate onset, tingling, rash, drop in bp, headache, itching of the skin, nausea, vomiting, diarrhea
- Antidote: antihistamines
17
Q
Muscle contraction and relaxation
A
- membrane depolarization-Ca++ released from the sarcoplasmic reticulum
- muscle contraction
- muscle relaxation
18
Q
muscle relaxation
A
- Ca++ back into sr
- parvalbumin binds free Ca
- facilitates movement back into the sr
- parvalbumin correlated with muscle relaxation rate
- more parvalbumin=faster relaxation time
19
Q
Allergies to fish
A
- parvalbumin levels in fish can be high in the fast twitch muscles that make up the bulk of the filet
- allergies are reaction parvalbumin
- parvalbumin differs between species
20
Q
pufferfish poisoning
A
- accumulate tetrodotoxin in pufferfish liver and gonads
- Na+ channel blocker
- class 1=extremely toxic
- also accumulate high saxitoxin concentrations
21
Q
real zombies
A
- haitian cultures-Bokurs used tetrodotoxin pufferfish to poison victims
- paralyzed, appear dead, comatose
- buried
- Bokur digs up the victim, gives them hallucinogen and makes them a slave
22
Q
nitrate as additive creates carcinogenic compounds
A
nitrate-curing meats and fish products
- antimicrobial activity and reacts with myoglobin and hemoglobin to form red nitrosylcompounds
- nitrate reacts with amines to form stable nitrosamines
- high temperature and acidic conditions increase rate of nitrosamine formation
- nitrosamines can alkylate DNA and cause mutations and cancer
- groups 1 carcinogens
23
Q
BBQ/cooking meat
A
- high temperature breakdown of carbohydrates and proteins forms polycyclic aromatic hydrocarbons and heterocyclic aromatic amines
- form DNA adducts
- group 2 carcinogen, stomach and colorectal cancers
24
Q
mycotoxins
A
- toxins produced by fungi
- single species may make several toxins
- many species could make the same toxin
- only certain strains will make toxins
- high infection rates on drought-stressed and insect-eaten plants
- high fungal growth rates when food stored at high humidity
- grow on plants, improperly stored food
- passed from animals to humans
25
aflatoxin toxins
- B1, B2, G1, G2
- modified furanocoumarins made via fungal polyketide biosynthesis
- highly/extremely toxic classes
- acute symptoms: abdominal pain, pulmonary edema, fatty infiltration and necrosis of the liver
- additive or synergistic with other liver carcinogens
26
aflatoxin B1
- metabolically activated in the liver
- cytochrome P450 covert into an epoxide
- binds to DNA at the guanine base, incorrect repairs of adducts can leads to cancer
27
Bt corn
- reduced levels of aflatoxin contamination
- expresses a protein normally made by soil bacteria
- toxic to some insects
- developed to increase yields by reducing insect damage
- decrease in insect damage leads to less fungal infestation, resulting in reduced aflatoxin levels
28
ergotism
- eating grains infected by fungus
- wet and overwintered grains
- sclerotia consumes a whole seed and replacing it with fungal hyphae
- caused by ergot alkaloids
29
ergometrine
- potent vasoconstriction drug
- hallucinogenic
- facilitate the delivery of the placenta and stop bleeding in childbirth
- WHO essential drug
30
ergotamine
- potent vasoconstriction drug
| - medically treats migraine headaches
31
egotism symptoms and outcomes
- gangrene-not enough blood flow to the extremities
- convulsions-disruption in serotonin levels
- hallucinations-disrupting certain neuro receptors
- spontaneous abortions-not enough blood flow to the developing child
32
exotoxins
- soluble toxins made and secreted by bacteria released by lysis of the bacteria
- proteins with enzymatic function
- partially degraded by cooking
- sufficient numbers avoid being digested in the gut and make it into the bloodstream
- can be made by living bacteria in contaminated food and press even after the bacteria is dead
33
endotoxins
- cell-associated substances that are structural lipopolysaccharide components of the outer membrane of gram-negative bacteria
- released from growing bacterial cells, released from dead bacteria
- hyperactive immune response-toxic shock syndrome
34
botulism
- exotoxin botulism produced by bacteria
- gram positive
- obligate anaerobic bacillus
- form spores
- resistant to heat, light, drying, radiation
- conditions for germination-anaerobic conditions, warmth, mild alkalinity
35
botulism discovery
- sausage poisoning
| - neuoparalytic toxin produced by anaerobic bacterium
36
BoNT mode of action
- binds to receptors on the outside of the neuron, up-take toxin via endocytosis
- translocation domain punches a hole through the endocytic vesicle so the protein escapes into the cytoplasm
- catalytic domain finds its target (protein involved in secretion) and cleaves it, destroying it
37
Catalytic domain cleaves SNARE
- vesicles containing neurotransmitters must first be docked by SNARE proteins
- botulinum toxin catalytic chain specifically cleaves these SNARE proteins, no neurotransmitters are released
- stops neurotransmission between neuronal muscle junctions causing flaccid paralysis
38
food borne botulism
- spores infect food
- toxin is produced and released into food when bacteria die
- cand be reduced through cooking
39
infant botulism
- spores germinate in gut and bacterial colony is established
- bacteria colony release toxins
40
wound botulism
-associated with IV drug use
41
botulism poisoning
- result in symmetric descending flaccid paralysis of motor and autonomic nerves
- symptoms: blurred vision, drooping eyelids, dry mouth, respiratory failure
- treatment: anti-toxin antibodies and stick the patient on a ventilator
42
medical botulism
- used to treat conditions when muscles contract when they should not
- botox blocks the nerve transmission that causes the muscle cells to contract
43
exotoxin in e coli
- non-pathogenic
- bacteria are really good at swapping DNA bits amongst species
- picked up genes that make them pathogenic
- acquired the genes to make shiga toxin
- cow guts-infect hamburger meat
44
shiva toxin structure and function
subunit a
-toxic catalytic bit, cleaves the 28S ribosomal RNA destroying ribosomes and halting all protein translation
subunit b
-interacts with a specific lipid cell membranes
-tricks cells into taking it in by endocytosis
45
shiva toxin
- primarily occurs in intestinal epithelial cells
| - acute hemorrhagic diarrhea and fever
46
hemolytic-ureic syndrom
- direct destruction of kidney cells from toxin
- direct nerve damage
- indirect destruction of red blood cells
- elderly and children
