Classes/Sources of Food Toxins Flashcards Preview

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Flashcards in Classes/Sources of Food Toxins Deck (58)
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1

A toxicant that was ALREADY present in the food naturally is:

endogenous toxin

2

What is a foodbourne toxicant?

A chemical compound in food that causes adverse health effects in consumer

3

What are the consequences of contaminants in food?

- foodbourne illness
- adverse reactions (intoxication, allergic reaction)
- Bans on export/trade
- damaged reputation of producer

4

Define "contaminants in food"

Substances NOT INTENTIONALLY added, but are present in food
Introduced during production/processing/storage/etc.
(could be at any or several stages)

5

True/False: rodent hair and insect fragments are considered to be contaminants, under the Codex Alimentarus

False

6

Name the 4 categories of food safety hazards:

- physical
- chemical
- microbiological
- allergens

7

The 3 main groups of food toxicants:

Naturally occuring toxicants
Synthetic toxicants
Endogenous toxicants

8

If a contaminant has an "adverse effect," what might if affect in the consumer? (8)

Morphology
Physiology
Growth/Development
Reproduction
Lifespan
Decreased functional capacity
Decreases stress tolerance
Increased susceptibility to other influences

9

What are some examples of plant and animal endogenous toxins?

Plant: Cyanoglycosides, Lectins, Glycoalkaloids

Animal: Estrogens

10

True/False: synthetic toxins can be intentionally introduced to food.

True. (adulteration, food fraud)

11

What product could potentially lead to cyanide poisoning in large quantities, due to endogenous toxins?

Bitter apricot kernels

12

What is the difference between naturally occuring toxins and endogenous toxins?

Endogenous: naturally present in the food itself; require methods to destroy to make food safe, or need to limit consumption

Naturally occurring: From natural sources but should not be present in the edible food itself - presence in food is due to contamination/spoilage

13

In the recent China milk scandal, what toxin was added to milk, and for what reason?

Melamine
To boost apparent protein content (fraud)

14

3 examples of mycotoxins:

Aflatoxins
Ochratoxins
Patulin

15

What is the cause of paralytic shellfish poisoning?

Algal growth -> produces saxitoxin

16

Naturally occuring toxins may be present from: (4)

- Fungal growth (mycotoxins)
- Algal growth
- Bacterial growth
- Improper preparation (pufferfish tetrodotoxin)

17

What is the main bacterial toxin of concern?

Botulinum toxin (cause botulism)

18

3 examples of algal toxin:

Saxitoxin
Domoic Acid
Brevetoxin

19

What is the toxin produced in fish by the eukaryote G. toxicus? What does consuming it cause?

Ciguatoxin
Ciguatera - nausea, tingling, vomiting (rarely fatal)

20

To properly identify hazards, you need to know: (2)

1. ADVERSE HEALTH EFFECTS
2. sources of exposure

21

What are some sources of synthetic toxins? (7)

- Agricultural chemicals
- Veterinary drugs
- Environmental contaminants
- Process contaminants
- Residues from packaging
- Cleaning chemicals/biocides
- Adulterants

22

What is the first step of risk assessment?

Hazard identification

23

How are adulterants different from other sources of synthetic toxins?

Intentionally added (food fraud)

24

the ____ is expressed as amount of chemical entering the body per body weight.

Dose

25

The 3 types of dose-response relationships:

threshold
non-threshold
essential nutrients

26

What parameters does the adverse effect of the toxin depend on? (4)

- Dose
- Duration/frequency of exposure
- type of food ingested
- other biological parameters (sensitivity, etc)

27

The amount of a substance per body weight that would cause fatality is the ____.

lethal dose

28

What is the key parameter for safety evaluation of chemicals in terms of toxicology?

LD50

29

How does the curve for essential nutrients differ from other toxins?

certain amount is necessary for life;
at low concentrations, adverse effect is high -> increasing dose will normalize (low harm)
BUT: increasing beyond required amount can cause increasing adverse effects.

so: U SHAPED CURVE

30

Describe the dose-response curves for threshold and non-threshold toxins. What accounts for their differences?

Threshold: S shaped curve (gradual increase, then steep slope, then plateau)
Non-threshold: constant slope

Threshold toxins: body has some TOLERANCE and detoxification ability. Lower amounts can be handled, but as dose increases, it overwhelms the detox mechanisms and becomes very harmful (steep slope)

Non-threshold: zero tolerance, even tiny amounts are harmful. (carcinogens, etc)

31

How is the dose-response curve established?

Animal tests
Feed increasing doses to animals, observe death rate (or rate of certain effect)
curve is dose vs % death (or effect)

32

A lower LD50 corresponds to (higher/lower) toxicity.

higher

33

What is the ED50?

Effective Dose
Dose that causes adverse effect in 50% of test animal population

34

Although today there is no distinction made between solid and liquid forms of toxins, which was previously classified as being more toxic and why?

Liquid; easier absorption/higher bioavailability -> lower LD50

35

If the adverse effect observed is death, then the median lethal dose is known as?

LD50

36

_____, found in bbq foods, is a class 1 carcinogen and classified as a _____.

benzopyrenes; genotoxin

37

Do LOAEL or NOAEL exist for genotoxins?

No; even tiny amounts will cause adverse effects (non threshold)

38

What are the WHO classes of pesticides (according to hazard level)?

Ia: extremely
Ib: highly
II: moderately
III: slightly

39

How are NOAEL/LOAEL determined?

Experimentally

40

What is NOAEL?

no observed adverse effect level
- point just below LOAEL, highest dose without adverse effects.

41

LOAEL and NOAEL only apply for ____ curves.

Threshold

42

True/False: for some heavy metals, too low of an exposure will have adverse effects.

True
Cu, Ni, Fe, Zn are all essential in the body at low levels; deficiency will cause disease

43

What is the LOAEL?

lowest observed adverse effect level
- first point on curve that is SIGNIFICANTLY DIFFERENT from control

44

Acute exposure is ______, while chronic exposure is ______.

acute: exposure within 24 hrs
chronic: AVERAGE daily exposure over several years to a lifetime

45

What are amygdalin and linamarin? Are they toxic?

cyanogenic glycosides
No; but breakdown will yield toxic cyanide

46

What might cause copper deficiency or excess?

Deficiency: Increased uptake of zinc, absorbance issues. (rarely due to diet)
Excess: acidic food leeching from copper container

47

Food toxicants have a wide range of:

physicochemical properties

48

Give an example of acute exposure, and of chronic exposure in the modern day food industry

Acute: Clenbuterol (vet drug) in Spain/Portugal - contaminated lamb/beef - cause tremors/tachycardia/nausea/dizziness

Chronic: Methylmercury - Minamata, Japan - in fish (bioaccumulative effect) - lead to Minamata disease (neurological effects, fetal defects)

49

"small" molecules are typically below _____. These are mostly ____ contaminants.

900Da
organic

50

What are some physicochemical properties? (5)

Size
Structure
Behavior as acid/base
Polarity
Volatility

51

The physicochemical properties of a chemical have implications in its: (2)

behaviour/stability (in food and in body system)
analytical methods

52

What are the larger sized contaminants?

Proteins

53

What are some nonpolar contaminants?

PCBs, DDT, chlordanes, oil residues

54

A highly volatile substance has a ____

high vapor pressure/low boil pt

55

Compounds may be classified as: (according to volatility)

nonvolatile
semi volatile
volatile

56

Most pesticides and antibiotics are (polar/nonpolar); so they are soluble in:

polar
water, protic organic solvents

57

What makes a compound an acid/base?

presence of IONIZABLE groups; charged by presence of acid/base

58

compounds with ionizable groups will have multiple ____ that change depending on ____.

forms
pH