Module 12 Flashcards
1
Q
Define toxicant.
A
A poison or a poisonous agent.
Poisons are chemicals that, in very small quantities, produce illness or death. Legally, a poison is defined as a chemical that has a lethal dose of 50 milligrams or less of chemical per kilogram of body weight.
When we refer to toxicants in food, we are generally referring to substances responsible for a whole spectrum of possible results, ranging from relatively minor discomfort or sickness to poisoning that can lead to death.
2
Q
Define: toxicity.
A
The intrinsic or inherent capacity of a substance to damage a biological system (produce injury) when tested by itself.
Substances vary in their toxicity, as reflected in their dose-response curves.
A toxicant can have an effect on several different functions within an individual. The individuals can vary among themselves with regard to the sensitivity of their different functions.
3
Q
Define: hazard.
A
A thing or action that can cause adverse health effects in animals (including fish), plants or humans. The capacity to produce injury under the circumstances of exposure.
4
Q
Why is hazard a more complex concept than toxicity?
A
Because it includes a consideration of conditions of use; in other words, two components are involved in assessing a hazard:
1. the inherent capacity to cause harm (toxicity), and
2. the ease or probability of contact between the substance and the target object.
“An extremely toxic chemical, such as strychnine, when sealed in an unopenable vial, can be handled freely by people with no chance that a poisoning will occur. Its toxicity has not changed, but it presents no hazard because no contact can be established between the chemical and people. Conversely, a chemical that is not highly toxic, such as boric acid, can be very hazardous when used in a manner that makes it readily available for accidental ingestion.” Dr. Ottoboni
5
Q
Define: risk
A
A function of the probability of an adverse health effect and the magnitude of that effect, consequential to a hazard; the likelihood of the occurrence and the magnitude of the consequences of an adverse event.
6
Q
Describe a dose response curve.
A
- The dose at which a substance begins to have an undesirable effect, that is, the upper limit of its “no effect” dose, is its threshold. This value is unique for each substance.
- The slope of the increasing dose-increasing effect portion of the curve is also characteristic of the particular substance. A chemical with a very steep dose-response curve offers very little flexibility in trying to avoid harmful exposure. A one- or two-fold difference in the amount of chemical consumed might be the difference between no-effect and serious consequences.
7
Q
List 6 naturally occurring toxicants (i.e., constituents).
A
- Cholinesterase inhibitors
- Cyanogenic glycosides
- Glucosinates
- Protease inhibitors
- Nitrites
- Allergens
8
Q
List 3 naturally occurring toxicants (i.e., contaminants).
A
- Mycotoxins
- Bacterial toxins
- Seafood toxins
9
Q
List 5 environmental toxicants.
A
- Food packaging residues
- Pesticide residues
- Heavy metals
- Animal drugs
- Radioisotopes
10
Q
Solanine in potatoes
A
Cholinesterase inhibitors
Constituents
By inhibiting cholinesterase, solanine disrupts the breakdown of acetylcholine, a neurotransmitter, leading to an accumulation of acetylcholine in the synapses.
This can result in symptoms of poisoning, including nausea, vomiting, diarrhea, headaches, and in severe cases, neurological symptoms like hallucinations and paralysis.
11
Q
Amygdalin in apple seeds
A
Cyanogenic glycosides
Constituents
Amygdalin is a type of cyanogenic glycoside.
When apple seeds containing amygdalin are crushed or chewed, enzymes in the seeds and in the human digestive system convert amygdalin into hydrogen cyanide.
Hydrogen cyanide interferes with cellular respiration by inhibiting the enzyme cytochrome c oxidase, which can be fatal in high enough doses.
12
Q
Sinigrin in cabbage
A
Glucosinates
Constituents
Sinigrin in cabbage is a type of glucosinolate that, when broken down by the enzyme myrosinase, forms bioactive compounds with potential health benefits.
13
Q
Protease inhibitors in soybeans
A
Protease inhibitors
Constituents
14
Q
Beta-lactoglobulin
A
Allergen
Constituent in milk
15
Q
Peanut or soy proteins
A
Allergens
Constituents
16
Q
Cholinesterase inhibitors
Constituents
A
Solanine in potatoes
17
Q
Cyanogenic glycosides
Constituents
A
Amygdalin in apple seeds
18
Q
Glucosinates
Constituents
A
Sinigrin in cabbage
19
Q
Protease inhibitors
Constituents
A
Protease inhibitors in soybeans
20
Q
Allergen
Constituent in milk
A
Beta-lactoglobulin
21
Q
Allergens
Constituents
A
Peanut or soy proteins
22
Q
Aflatoxin
A
Mycotoxin
Contaminant in mouldy meat
23
Q
Patulin
A
Mycotoxin
Contaminant
24
Q
Ochratoxin A
A
Mycotoxin
Contaminant
25
Vomitoxin
Mycotoxin
## Footnote
Contaminant found in wheat
26
Zearalenone
Mycotoxin
## Footnote
Contaminant
27
*Botulinum* toxin
Bacterial toxin
## Footnote
Contaminant
28
*Staphylococcal* toxin
Bacterial Toxin
## Footnote
Contaminant
29
Histamine
Seafood toxin
30
Saxitoxin
Seafood toxin
31
Domoic acid
Seafood toxin
32
Tetradotoxin
Seafood toxin
33
Seafood toxins [4]
* Histamine
* Saxitoxin
* Domoic acid
* Tetrodotoxin
34
Bacterial toxins [2].
* Botulinum toxin
* Staphylococcal toxin
35
Mycotoxins [5].
* Aflatoxin
* Patulin
* Ochratoxin A
* Vomitoxin
* Zearalenone
36
Food packaging residues
Monomers of plastic resins
## Footnote
Environmental toxicant
37
Monomers of plastic resins
## Footnote
Environmental toxicant
Food packaging residues
38
Pesticide residues [3].
* Herbicides
* Insecticides
* Fungicides
## Footnote
E.g., malathion residues on fruit
39
Heavy metals [3].
* Lead
* Mercury
* Cadmium
## Footnote
E.g., lead in veg; mercury in large ocean fish like swordfish
40
Animal drugs [2].
* Antibiotics
* Hormones
## Footnote
E.g., penicillin in milk
41
Radioisotopes
* From soil or
* From radioactive fallout
42
What is the basis for distinction between Natural Constituents and Natural Contaminants?
* **Constituents** are chemical entities that are part of the normal composition of a food material - they are not the result of some external organism or activity.
* **Contaminants**, on the other hand, are present because of the presence of moulds or bacteria, or because the plant or animal was grown in a condition which permitted the toxicant to become part of the food.
43
What is the distinction between natural and environmental toxicants?
* Less clear cut but may be generally determined by their origin.
* For example, we might be able to prevent the growth of moulds, but moulds are nevertheless naturally present in the environment.
* Pesticides, however, are introduced into the environment by us and while not intended to become part of the food, some do to a certain extent.
* Mercury and lead can enter the food supply because of heavy natural deposits in the soil, but in fact are found in food predominantly because we use these metals in a wide variety of ways.
44
Describe the perceptions of hazards in the food supply held by popular belief compared to regulatory agencies.
It is interesting to note that what is perceived by popular opinion to be the greatest hazard is indeed considered to be the least important by regulatory agencies, and vice-versa! Regulatory agencies base their ratings on a much broader information base (including statistical or epidemiological evidence) than does the general public.
45
What is a glycoalkaloid-cholinesterase inhibitor?
* Refers to a variety of chemicals which are able to inhibit the activity of the enzyme **cholinesterase**
* The enzyme is found in nerve tissues and plays an important role in the transmission of nerve impulses.
* When this enzyme's function is inhibited, nerve function is affected.
## Footnote
Solanine is an example of such an inhibitor (found in high levels in greening potatoes)
46
Where is solanine found?
* Solanine can is found in potatoes, normally at levels of 2-13 mg/100 g fresh weight, the bulk of market potatoes probably contain only 3-6 mg/100 g.
* Levels as high as 80-100 mg/100 g, have been reported particularly if the potatoes have undergone **greening** (reaction of potato tubers on exposure to sunlight).
* Solanine is insoluble in water and is not lost or destroyed when potatoes are cooked.
* Because it is found primarily in the skin of potatoes, the peeling of potatoes reduces the concentration markedly.
47
Solanine is destroyed when potatoes are cooked.
True or False?
False.
Solanine is insoluble in water and is not lost or destroyed when potatoes are cooked.
48
Solanine is not destroyed when potatoes are cooked.
True or False?
True.
Solanine is insoluble in water and is not lost or destroyed when potatoes are cooked.
49
How can solanine concentration in potatoes be reduced markedly?
By peeling potatoes, since solanine is found primarily in the potato skin
50
What are clinical symptoms of solanine poisoning? [3]
* GI disturbances
* Neurological disorders
* Death
51
What are the symptoms of ingested (rather than injected) solanine exposure?
* Drowsiness
* Increased sensory activity
* Difficulty breathing after any oral dose of 100 mg (~ 2-8 mg/kg body weight)
* Higher doses may cause vomiting and diarrhea
## Footnote
Solanine is not readily absorbed and is fairly rapidly excreted by way of the feces and the urine.
52
Although the chemical solanine itself is quite a potent toxicant, the hazard of solanine poisoning by consumption of potatoes is quite low. Why is that?
* Potato growing and handling practices minimize the opportunity for greening, and hence minimize the production of abnormally high levels of solanine.
* Seed potatoes that are genetically low in solanine content are used, and during the growing season the potato plants are hilled, thereby decreasing the exposure of the potato to light.
* After harvesting, potatoes are put into storage facilities which minimize exposure to light.
* Consumers who ignore the hazards of consuming potatoes that have turned green during improper storage at home would face a high risk of poisoning by solanine!
53
What are cyanogenic glycosides?
* They yield hydrogen cyanide (HCN) upon treatment with acid or particular hydrolytic enzymes
* They are found widely in plants, and also occur in ferns, moths and insects (e.g., cassava, sweet potato, yam, maize, bamboo, sugar cane, peas, lima beans, almonds, lime, apple, pear, cherry, apricot, plum)
* Cyanide is very rapidly absorbed from the GI tract and produces recognizable symptoms at both fatal and non-fatal levels.
54
How does death result from fatal doses of HCN?
* General anoxic condition caused by the inhibition of cytochrome oxidase, with which the HCN complexes
* Cytochrome oxidase is an important component of the oxidative phosphorylation cycle which occurs in the mitochondria of cells.
* Inhibition of this enzyme causes the death of cells.
* Since the HCN binds reversibly to the cytochrome oxidase, non-fatal doses permit recovery by employing respiratory exchange and metabolic detoxification processes.
## Footnote
For humans, the minimum lethal dose of HCN taken orally has been estimated to be between 0.5-3.5 mg/kg of body weight.
55
What is an example of a cyanogenic glycoside?
* Amygdalin found in bitter almonds and some fruit pits and apple seeds
56
Which enzymes are responsible for the hydrolysis of cyanide glycosides?
* Beta-glycosides, which are highly specific for the beta-glycosidic linkage that is characteristic of cyanogenic glycosides.
* Hydrolysis of cyanogenic glycosides can occur during the cutting, crushing, bruising or maceration of tissue prior to consumption, or can be initiated upon the maceration of the tissue during eating.
* Cyanide poisoning can therefore occur when enough of a plant material that is rich in cyanogenic glycosides and enzymes is consumed, or when such material has been prepared with insufficient care to remove the HCN accumulated during preparation.
## Footnote
In parts of the world where some of these cyanide-producing plants are used extensively for food, means of preparation have been developed to remove or hydrolyze the glycosides and to destroy the ß-glucosidase that is present. While these steps minimize the hazard, they do not completely eliminate it.
57
It is important, however, that while the cyanide-producing capacity of a plant is important in determining its toxicity, there are other factors which must also be considered. What are they? [5]
* The size and kind of subject
* The speed of ingestion
* The type of food ingested simultaneously with the cyanogen
* The presence of active degradative enzymes both in plant and in the subject's digestive tract
* The subject's ability to detoxify the HCN
## Footnote
The hazard associated with the presence of cyanogenic glycosides in food for those individuals who consume large quantities of the affected plant foodstuff is much more significant than for those who accidentally eat the occasional apple seed or apricot kernel.
58
Describe the natural toxicant: protease inhibitors.
* Proteinaceous compounds are found in many of the legume species.
* They have the ability to make a complex and thereby interfere with certain proteolytic enzymes.
* Proteins need to be hydrolyzed into their constituent amino acids by digestive enzymes such as trypsin and chymotrypsin.
* If these enzymes are rendered inactive by complexing inhibitors, the body cannot fully hydrolyze the proteins, thereby **creating the possibility of amino acid deficiencies**.
59
Describe the natural toxicant: nitrates.
* Widely found in *constituents* of plant materials, especially green leafy plants
* Nitrates themselves are not very toxic; however, bacteria can reduce them to **nitrites**.
* A primary concern about nitrites is their ability to interact chemically with hemoglobin, interfering with the blood's ability to transport the required oxygen to the body's cells.
* By a rather complex series of reactions, not only bacteria but also metabolic pathways within the digestive system of humans can utilize nitrate/nitrite as a precursor for the formation of **nitrosamines**, potent carcinogens.
60
What is the primary concern about nitrates?
* Bacteria reduce them to nitrites, which are a precursor for nitrosamines, potent carcinogens
61
Describe the natural toxicants: allergens.
* Have the ability to induce *allergic reactions* in sensitive individuals.
* Foods that are most frequently reported to cause allergic responses are cereals such as wheat, rye and rice; legumes such as peas, peanuts and soybeans; tree nuts; milk; eggs; and seafood such as shrimp, crab and lobster.
* The case of allergens provides a good example of the need to consider individual (genetic) differences in assessing risks and hazards.
* For most of us, consumption of the foods listed above does not pose any significant risk.
* However, for someone who is severely allergic to a particular food or food component, accidental ingestion may lead to a life-or-death situation!
62
What are mycotoxins?
* Substances produced by mould which may be toxic
* Mycotoxins may occur by direct contamination (due to mould growth on the food) or by indirect contamination (by using a food ingredient that was contaminated).
* Mycotoxins can be highly toxic to the body, some have been known to cause cancer in animal tests, others are mutagenic and able to cause mutation, and others are teratogenic and capable of causing deformities in embryos.
* Mycotoxins are **invisible to the eye**, are often **unchanged by heat** and can potentially spread throughout a product.
* As a result, any sign of visible mould could indicate that the product contains mycotoxins and should be thrown away.
## Footnote
Examples: aflatoxins, sterigmatocystin, ochratoxin A, citrinin and patulin
63
Which mycotoxins are of greatest concern and why?
* Alfatoxins
* They are potent liver toxins in all animals
* The different aflatoxins (B1, B2, G1, G2, M1and M2) may be found in various commodities including peanuts, corn, wheat, rice, cottonseed, copra, nuts, milk, eggs, and cheese.
64
Aflatoxins are not directly regulated in The Food and Drugs Act.
True or False?
True.
## Footnote
A challenge to the contention that aflatoxin was injurious to human health caused a court to dismiss a charge of selling contaminated peanut butter that contained greater than 20 ppb of aflatoxin. To get around that problem, the act and regulations were changed to state that peanut butter would be considered contaminated, and therefore not fit for sale, if it contained aflatoxins in excess of 15 ppb.
65
Aflatoxins are directly regulated by The Food and Drugs Act.
True or False?
False.
They are not directly regulated.
## Footnote
A challenge to the contention that aflatoxin was injurious to human health caused a court to dismiss a charge of selling contaminated peanut butter that contained greater than 20 ppb of aflatoxin. To get around that problem, the act and regulations were changed to state that peanut butter would be considered contaminated, and therefore not fit for sale, if it contained aflatoxins in excess of 15 ppb.
66
The benefit of saving a mouldy product may outweigh the risk of mycotoxins in some cases. What should be considered when encountering a mouldy food?
* Was the food refrigerated? Did the mould grow on the product while it was refrigerated? If it has, likely, the product does not contain aflatoxins (these are not normally produced under refrigerated conditions).
* The amount of mould on the product should also be considered, for example, if there is a tiny green mould colony on a large block of cheese, the benefits of cutting that portion off (about 2.5 cm around and beneath the cheese) are much greater than the risks involved.
* The type of food the mould is growing on should also be considered; “trimming” mould should not be done on soft, semi-solid, or liquid foods, or foods like jams/jellies and baked products. In these products, the ability of the mould toxins to spread (via the mould mycelia) is much greater. In these cases, the risks outweigh the benefits of saving the product.
67
What are the two most important bacterial toxins?
* Those produced by *Clostridium botulinum* and *Staphylococcus aureus*
* Food poisoning caused by these two types of bacteria can be considered as due to **food intoxications**, because it is the chemical toxin produced by the bacteria, as opposed to the bacteria themselves (in the case of foodborne infections), that produces the toxicity.
* The toxins can produce illness even if the bacteria that produced them have been killed already.
68
What is scomboid poisoning?
* Due to an allergic-type reaction to high levels of histamine or a histamine-like substance.
* Histidine, a naturally occurring amino acid which is particularly high in scomboid fish, is converted to histamine by bacterial action on the dead flesh of fish.
* This process is dependent on holding time and temperature during transportation and storage.
## Footnote
It is also important to note that histamine and other vasoactive amines may be found in many fermented foods such as cheese, wine and pickled herring.
69
What are symptoms of histamine poisoning?
* Vaso-active properties which will cause blood pressure changes
* Poisoning is known to result from eating scombroid fishes, i.e. fish of the Scombridae and Scomberesocidae families, including tuna, bonito and mackerel.
* The poisoning results in nausea, vomiting, facial flushing, headache, epigastric pain, thirst, itching of the skin and hives.
* The effects usually subside within 12 hours but in some severe cases, death has resulted.
70
What is responsible for the condition known as paralytic shellfish poisoning?
* Saxitoxin
* Result of consuming shellfish like oysters, mussels, and clams, which contain the toxin
* This toxin can also accumulate in the liver of crustaceans like crabs and lobsters.
## Footnote
The toxin is ineffective against the shellfish, which can absorb the toxin, concentrate it in their tissues and pass it onto the species feeding on them (in this case, humans).
71
What are the symptoms of saxitoxin?
* Tingling in the mouth, lips and fingertips.
* Sight and hearing are modified in much the same way as caused by alcohol intoxication.
* Speech becomes incoherent.
72
What is this?
* Saxitoxin is a contaminant which the shellfish consume as part of their occasional food supply.
* The shellfish feed on a variety of microscopic plankton among which are certain toxic dinoflagellates.
* At certain times of the year, under certain conditions, these dinoflagellates increase greatly in number and concentration in the oceans.
* This is often referred to as a bloom or "red tide."
* During red tide, the shellfish are exposed to and concentrate large amounts of saxitoxin.
* Saxitoxin is extremely stable and takes a long time to be flushed from the tissues of the shellfish.
* It is for this reason that during red tide season and for a considerable time afterwards, harvesting shellfish is prohibited.
## Footnote
Saxitoxin is considered one of the potent toxins, the minimum lethal dose being about 1.0-4.0 mg/kg of body weight. However, because of the variability in the concentration of the toxin in the shellfish, it is very difficult to indicate a maximum amount of shellfish tissue that can be consumed. This is obviously a situation which is not at all hazardous to anyone who rarely harvests and consumes shellfish. However, the hazard increases significantly, for those who are uninformed and are fond of shellfish, particularly those harvested in areas known to be subject to red tide situations.
73
What is the cause of amnesic shellfish poisoning?
* Domoic acid, which can accumulate in filter-feeding shellfish like clams, mussels, oysters, and scallops
* Routine testing for the toxin is conducted, and areas in which the toxin occurs in the shellfish are closed to harvesting.
* Thus, the risk of amnesic shellfish poisoning is high only for individuals who choose to ignore signs indicating the closure of areas to shellfish harvesting.
74
What are the effects of domoic acid poisoning?
* Amnesic shellfish poisoning
* Domoic acid is a neurotoxin capable of causing lesions in the central nervous system
* Gastroenterititis
* Memory loss (even five years after the incident)
75
What is fugu poisoning?
* Tetradotoxin is the chemical of interest in puffer-fish or fugu poisoning
* This toxin is found mainly in the ovaries, liver, intestine, skin, and spawn of the pufferfish
* It is thought to be synthesized by a bacterial species *Pseudoalteromonas tetraodonis* which is associated with the pufferfish.
76
What are symptoms of fugu poisoning?
* Begin with a tingling sensation on the fingers, toes, lips and tongue a few minutes after eating the fish.
* Nausea, vomiting, diarrhea and epigastric pain appear in some cases.
* As the poisoning progresses, reflexes of the pupil and cornea are lost and the patient increasingly experiences paralysis and respiratory distress.
* If the dose is sufficiently large, death will result, caused by respiratory paralysis.
* The mode of action of tetrodotoxin is considered to be essentially the same as saxitoxin. As with saxitoxin, a lethal dose for humans is thought to be about 1.0 - 4.0 mg/kg.
77
Describe preventive measures against fugu poisoning.
* Entirely restricted to diligence during preparation of the fish
* When gutting and cleaning the fish, care must be exercised so as not to contaminate the flesh with even the minutest amount of viscera, ovaries or spawn.
* Pufferfish poisoning continues to be a problem in Japan, affecting 30 -100 persons per year, and primarily as a result of home preparation and consumption, not from commercial sources of the pufferfish.
* Again we have an example of an extremely toxic chemical but one whose hazard is quite variable.
* Lovers of fugu are at considerable risk, while those who do not consume this food are at absolutely no risk.
78
What do environmental contaminants include? [4]
* products of industrial activity (e.g., lead, mercury, dioxins, polychlorinated biphenyls, radioisotopes)
* products of agricultural activity (e.g., pesticide and herbicide residues, antibiotic residues)
* products of food processing (e.g., packaging residues)
* naturally occurring environmental toxicants (e.g., mercury, radioisotopes)
79
What is the number of foodborne illness that occur in Canada each year?
~ 4 million!
80
Contamination of food can be of different etiology, including [5].
* Microbiological
* Parasitic
* Plant
* Animal
* Chemical
81
What is responsible for the majority of foodborne disease?
Microbiological agents
82
Associated with the consumption of undercooked pork
*Trichinella spiralis*
## Footnote
Parasite
83
[...] is associated with consumption of undercooked pork.
*Trichinella spiralis*
## Footnote
Parasite
84
Associated with consumption of undercooked fish or raw fish
*Anisakis simplex*
## Footnote
Parasite
85
[...] is associated with the consumption of undercooked or raw fish.
*Anisakis simplex*
## Footnote
Parasite
86
Give some examples of the sources of foodborne diseased arising from the consumption of plants.
* Amanita mushrooms
* Taro leaves
* Green potatoes
* Toxic algae in spirulina in protein supplement tablets
87
Illness arising from poisonous animals usually occur as a consumption of [...].
shellfish containing paralytic toxins
88
Chemicals in contaminated foods that cause foodborne disease have included [4].
* Tin in canned foods arising from corrosion inside the metal can
* Residues of cleaning and sanitizing agents in food
* Products of rancid fats in foods
* Excesses of some ingredients such as monosodium glutamate
89
Define: incident.
* Occurrence of foodborne illness
90
Define: outbreak.
* An incident in which two or more people experience a similar illness after ingestion of the same food and where epidemiological evidence implicates the food as the source of the illness.
91
What is considered a single **case** in foodborne illness?
* A person who has been ill following the consumption of food considered to be contaminated based on epidemiological evidence.
92
What do outbreaks/single cases of unknown etiology refer to?
* Situations where epidemiological evidence implicates a common food source but where laboratory analysis fails to identify the etiological agent.
93
These are the number of cases reported in BC - what do they represent?
* the "tip of the iceberg"
* only 1-4% of all foodborne disease outbreaks are reported and documented
94
What are some of the reasons that only some of foodborne disease outbreaks are documented? [4]
* many people do not report to a physician when they suspect they are suffering from foodborne disease;
* actual cases of the foodborne disease may be mistakenly diagnosed as having other sources (environmental, unknown sources);
* many people may attribute a mild case of foodborne illness as being due to the "24-hour flu," a "virus," or "eating too much"'
* sometimes people report that they suspect they are suffering from foodborne illness but the physician does not report the case to local health units or, if reported, the case may not be sufficiently well researched and reported by health units to the provincial health authorities.
95
Most cases of foodborne illness are only recognized when [...]
at least two or more people become sick after eating a meal or food product in common
96
The CFIA reports that each year only about [...] cases of foodborne illness are reported from which approximately [...] die.
If one were to add the costs of foodborne disease caused by other organisms and other agents, the total costs become staggering - over [...] dollars in Canada.
The CFIA reports that each year only about **10,000** cases of foodborne illness are reported from which approximately **30** die.
If one were to add the costs of foodborne disease caused by other organisms and other agents, the total costs become staggering - over **1.3 billion** dollars in Canada.
## Footnote
The cost of salmonellosis has been estimated at $850 million per year in hospitalization costs and lost income.
97
List 6 pathogenic microorganisms.
98
Discern between food intoxications and foodborne infections.
* In the case of foodborne **intoxications**, toxic substances are produced in the foods as by-products of the microorganisms before consumption, and cause the symptoms of foodborne illness upon ingestion.
* Foodborne **infections** result from the ingestion of viable microorganisms in the food at the time of consumption; these pathogenic microorganisms multiply and grow in the host, causing the symptoms of foodborne illness.
99
Give two examples of organisms causing foodborne intoxications.
* *Clostridium botulinum*
* *Escherichia coli* O157:H7 (Shiga toxin)
100
What are the foods associated with botulinal toxins?
* Low acid foods in anaerobic conditions. Improperly home-canned, vacuum-packed, poorly refrigerated foods
* Baked potatoes wrapped in foil
* Spores have been detected in vegetables such as carrots, potatoes and fruit (contamination with soil), in fresh and processed meats and honey and corn syrup.
101
How is botulism prevented?
* Commercially sterile after processing must receive a "botulinum cook" (12 D)
* Use sodium nitrite for cured meats
* Properly refrigerate vegetable/fruit juice.
* Honey, corn syrup and molasses must not be fed to infants < 1 year of age.
* Pasteurization of honey **does not** inactivate the spores.
102
[...] are among the **most toxic substances** known.
* Botulinal toxins
* Estimated LD50 for humans 1ng/kg body weight
## Footnote
Dizziness, double vision, difficulty swallowing, respiratory or cardiac paralysis, death (12-36 hrs)
103
What foods are commonly associated with shiga toxin?
* Undercooked ground meat
* Raw milk
* Unpasteurized apple juice/cider
* Lettuce
* Spinach
* Alfalfa sprouts
* Contaminated water supply (outbreak in Walkerton, Ontario)
104
How can food intoxication with shiga toxin be prevented?
* Practice good food sanitation and handwashing.
* Properly handle and cook foods.
* *E. coli* is killed by normal cooking and pasteurization, as well as ionizing radiation, but is able to survive in acidic conditions (e.g. apple juice).
* It does not grow well at temperatures below 8°C.
105
What are symptoms of botulism?
* Dizziness
* Double vision
* Difficulty swallowing
* Respiratory or cardiac paralysis
* Death
* Onset 12-36 hrs
106
What are symptoms of shiga-toxin poisoning?
* Bloody diarrhea
* Kidney failure
* Hemolytic uremic syndrom (HUS) in severe cases (12-72 hours)
107
Give 2 examples of microorganisms associated with foodborne infection.
* *Salmonella*
* *Listeria monocytogenes*
108
What foods are commonly associated with *Salmonella* spp.
* Raw meats and poultry
* Eggs (about 60% of chickens sold in the retail market are contaminated with Salmonella)
* Milk and dairy products
109
What symptoms are associated with *Salmonella* spp. infection?
* Nausea
* Fever
* Vomiting
* Abdominal cramps
* Diarrhea
* 6-48 hours onset
110
How is infection with *Salmonella* spp. prevented?
* *Salmonella* spp. are easily killed by heat (normal cooking and pasteurization processes) and ionizing energy
* They survive freezing and dehydration.
* Consequently, frozen and thawed poultry can be just as contaminated as fresh poultry.
111
What are the symptoms of infection with *Listeria monocytogenes*?
* Flu-like
* Meningitis
* Septicemia
* Pneumonia
* Birth defects
* Stillbirth
* 1 day - 3 weeks onset
112
What foods are commonly associated with *Listeria monocytogenes*?
* Raw milk
* Dairy products
* Vegetables
* Fish
* Meat
113
How is listeriosis prevented?
* The bacteria is capable of growing slowly on foods during storage in the refrigerator and appears to be fairly tolerant to salt.
* It is easily killed by proper cooking and pasteurization techniques.
* Refrigerate raw materials and high-risk foods below 4°C.
114
Give 2 examples of foodborne illnesses caused by viruses.
* Hepatitis A
* Norovirus
115
What are the symptoms of Hepatitis A?
* Fever
* Nausea
* Vomiting
* Abdominal pain
* Fatigue
* Swelling of the liver
* Jaundice
* Onset 10-50 days
116
What foods are commonly associated with Hepatitis A?
* Foods prepared with human contact
* Contaminated water
117
How is Hepatitis A infection prevented?
* Wash hands
* Practice good personal hygiene
* Avoid raw seafood
118
What are the symptoms of norovirus?
* Vomiting
* Diarrhea
* Headache
* Fever
* Onset 24-48 hours
119
What is commonly associated with norovirus?
* Sewage
* Contaminated water
* Contaminated salad ingredients
* Raw seafood
* Infected food workers
120
How is norovirus infection prevented?
* Use potable water
* Practice good personal hygiene
* Cook all seafood
121
What is the effect of preparation of food several hours in advance & improper storage?
favours growth of pathogenic bacteria and/or formation of toxins
122
What is the effect of insufficient cooking or reheating of food?
not sufficient heat application to eliminate/reduce pathogens
123
What is the effect of inadequate cooking of foods?
permits survival of pathogens, allowing them to grow to sufficiently large numbers
124
What is the effect of cross-contamination?
allowing uncontaminated food to become contaminated by improper handling of food
125
What is the effect of poor personal hygiene?
can promote cross-contamination
126
Why were foods implicated in foodborne disease outbreaks consumed, if they were so heavily contaminated with disease-causing microorganisms?
Pathogenic bacteria do not alter the colour, odour, flavour, or texture of food
127
Those who are at risk of foodborne illness (e.g., the elderly, the very young, pregnant women, immunocompromised) should be particularly careful about which foods?
* Raw meat
* Raw fish
* Milk
* Eggs
* Deli meats
* Soft cheese
* Uncooked sprouts
* Liver pate
* Unpasteurized fruit juices/cider
## Footnote
They should also take extra care in washing or peeling fresh fruits and vegetables or may cook these before eating.
128
Where are the top 4 places where food can be mishandled and lead to foodborne disease incidents?
1. Food service establishments
2. Food processing establishments
3. Retail Food establishments
4. Homes
129
What can be done to safeguard food safety?
* Choose foods processed for safety (i.e., pasteurized products over unpasteurized)
* Cook foods thoroughly
* Eat cooked foods immediately
* Store food promptly and carefully.
* Perishable and "cold" foods should be kept "cold" below 4°C until ready to cook or eat.
* Avoid the "Temperature Danger Zone" (TDZ) which is from 4°C to 60°C (40-140°F). Bacteria can grow and/or produce toxins in food if left in the TDZ.
* Reheat cooked foods thoroughly
* Avoid cross-contamination.
* Do not allow any contact between raw food or its traces and cooked food
* Wash hands repeatedly
* Keep all kitchen surfaces clean
* Do not let anyone with diarrhea or infected sores prepare food
* Wash all fruits and vegetables before eating
* Finally, if in doubt, throw it out!
130
What is the TDZ?
* The "Temperature Danger Zone" (TDZ) which is from 4°C to 60°C (40-140°F).
* Bacteria can grow and/or produce toxins in food if left in the TDZ.
131
What are the 7 principles in a HACCP system?
## Footnote
Hazard Analysis and Critical Control Points
1. Identify hazards
2. Determine the critical control points (CCPs)
3. Establish control measures (critical limits or thresholds
4. Establish procedures to monitor CCPs
5. Establish corrective actions
6. Keep records
7. Verify procedures
132
How important is hand washing?
* The following figure dramatically illustrates the importance of washing hands thoroughly after handling raw meats.
* In this experiment, a previously sanitized hand was rubbed with a cube of raw pork for about 15 seconds.
* The hand was then pressed gently onto a 9" agar plate and labeled as "soiled hand" (A).
* Hands were again washed with Hibitane hand sanitizer (4% w/v chlorhexidine gluconate) for 30 seconds and the right hand was gently pressed onto a second agar plate labeled as "washed hand" (B).
* Both plates were incubated at room temperature for 2 days.
133
If cheddar cheese is stored in the refrigerator has mould present, you can simply trim it.
True or False?
True.
134
If cheddar cheese is stored in the refrigerator has mould present, you should throw it away.
True or False?
False.
If cheddar cheese is stored in the refrigerator has mould present, you can simply trim it.
135
A risk and hazard are the same things.
True or False?
False.
136
A risk and hazard are not the same things.
True or False?
True.
137
An opened jar of jam in the fridge with visible mould present should be thrown out.
True or False?
True.
138
An opened jar of jam in the fridge with visible mould present can simply have the mould removed.
True or False?
False.
An opened jar of jam in the fridge with visible mould present should be thrown out.
139
All food borne disease is due to consumption of microorganisms.
True or False?
False.
140
Not all food borne disease is due to consumption of microorganisms.
True or False?
True.
141
*E. coli* is an example of a food intoxication.
True or False?
True.
142
*E. coli* is an example of a food infection.
True or False?
False.
*E. coli* is an example of a food intoxication.
143
*Salmonella* is an example of a food infection.
True or false?
True.
144
Salmonella is an example of a food intoxication.
True or False?
False.
Salmonella is an example of a food infection.
145
Histamine
Scomboid poisoning
146
Saxitoxin
Paralytic shellfish poisoning
147
Domoic acid
Amnesic shellfish poisoning
148
Tetrodotoxin
Puffer (fugu) poisoning
149
Scomboid poisoning
Histamine
150
Paralytic shellfish poisoning
Saxitoxin
151
Amnesic shellfish poisoning
Domoic acid
152
Puffer (fugu) poisoning
Tetrodotoxin
153
A new apple is on the market. When some people consume it they get a very upset stomach. Scientists have isolated a protein produced by the apple as the cause. What kind of toxicant does this represent?
Constituent
153
What is an example of an environmental toxicant?
Lead
154
When producing canned soup through commercial sterilization, the main concern is of clostridium botulinum. What type of toxicant does *C. botulinum* represent?
Contaminant
155
Which is an example of a contaminant?
Aflatoxin
156
What is an example of a constituent?
Amygdalin
