Toxicology - deck VI

Question 1

DES

Answer 1

Diethylstilbestrol (DES) is a synthetic estrogen.

was used during the 1950s and later to accelerate the weight gain of bovines and sheep.

When this hormone was given to pregnant women to avoid miscarriages, both the teratogenic and carcinogenic side effect of DES appeared.

The use of DES and zeranol as growth stimulators is prohibited in the EU.

Question 2

Zeranol is an

Answer 2

estrogenic hormone obtained from mycotoxin zearalenone, is highly hepatotoxic and produces hematological alterations at high doses.

The use of DES and zeranol as growth stimulators is prohibited in the EU.

Question 3

Veterinary drugs - coccidiostatics or anticoccidials are added to

Answer 3

feed to combat with coccidioses caused by enteric
protozoan parasites (Coccidia).

At risk are poultry and rabbits.
Residues of coccidiostatics have been discovered in hen eggs.

Question 4

monensin, narasin, salinomycin, and other polyether ionophorous antibiotics are used for treatment of

Answer 4

coccidioses

Question 5

the most common coccidiostatic

Answer 5

Polyether calcium ionophore lasalocid is the most common coccidiostatic, has attracted special attention, esp. in the UK.

In 2003, over 12% of the eggs tested for antibiotics in the UK were contaminated with this toxic antibiotic.

Some of the eggs were found to have much higher levels of
lasalocid than ever recorded before in the UK.

Question 6

In the last years, there have been an increasing number of incidences of lasalocid residues found in eggs.

A broader survey of spread of coccidiostatic residues in eggs in eight different European countries revealed that about ?% of the samples analysed contained one or more of the nine
anticoccidials in concentrations ranging from 0.1 to 63 µg/kg.

Answer 6

A broader survey of spread of coccidiostatic residues in eggs in eight different European countries revealed that about 36% of the samples analysed contained one or more of the nine anticoccidials in concentrations ranging from 0.1 to 63 µg/kg.

Salinomycin and lasalocid accounted for more than 60% of all positive samples.

Question 7

It is hypothesized that there may be a potential link between Sudden Adult Death Syndrome via cardiac failure and the consumption of

Answer 7

lasalocid residues in food, particularly in eggs, although there is no clear scientific evidence.

lasalocid is cocciostatic drug used in farm animals

Question 8

In the EU, food raw material of animal origin is analysed for
anthelmintics like (2)

Answer 8

ivermectin, levamisole, and others according to a respective national monitoring program.

Question 9

the most toxic anthelmintic

Answer 9

Special attention is paid to ivermectin (IM), the most toxic anthelmintic.

It is available in a variety of formulations, used for treatment of dogs (LD50 = 80 mg/kg), cats, horses, cattle, sheep, and swine.

Question 10

The avermectins are

Answer 10

neurotoxins, which have been successfully used in the treatment of helmintic parasitic infections of terrestrial
farm animals and also of river blindness (disease caused by infection with the parasitic worm in humans.

Question 11

The use of β-agonists as

Answer 11

growth stimulators is prohibited in the EU countries.

Clenbuterol is allowed to be used to treat diseases of respiratory organs as well as birth complications.

Acute clenbuterol toxicity resembles that of other β2-adrenergic agonists.

Question 12

Thyreostatics do what

Answer 12

reduce (or stabilize) the production of thyroid hormones

The thiourea derivatives used for this purpose are carcinogenic. The use of thyreostatics is either completely prohibited or allowed only for some medicinal purposes in the EU.

Question 13

The purpose of primary food processing is

Answer 13

increasing of safety, quality and palatability as well as simplification of the end-processing of food.

Question 14

Novel technologies for food processing are: (3)

Answer 14

Novel technologies are, for example, UV-radiation, use of pulsatory electric field and high-pressure pasteurization.

New food additives and packaging materials are being implemented.

Question 15

During both primary and secondary processing an endless number of different physico-chemical processes may occur that result in:

Answer 15

1. Partial or complete degradation or removal of nutrients and other components that may reduce food quality and digestibility.
2. Formation of a myriad of new substances, so-called neoformed compounds, from the food itself, including potentially toxic ones.

Question 16

During processing, various chemical compounds are formed that often

Answer 16

strengthen or weaken (antagonize) the effects of each other.

Furthermore, most of them are unknown for us.

Question 17

What is Maillard reaction?

Answer 17

Non-enzymatic browning

During thermal processing of foods (drying, roasting, cooking) multistep chemical reactions between amino acids and reducing saccharides (aldoses and ketoses) can occur.

The Maillard reaction is a chemical reaction between amino acids and reducing sugars that gives browned food its distinctive flavor.

Question 18

acrylamide or propenic acid amide has been

Answer 18

widely used during decades in various spheres of life, mostly (99.9%) for manufacturing of gelly polyacrylamide (PAA).

PAA, which by itself is of low toxicity to mammals, is used in purification of wastewaters, in
manufacturing of paper and cellulose, in the cosmetic industry for shampoos and perfumes, as a soil conditioner in the agriculture, and in chemical laboratories for preparation of analysis gels.

Question 19

Acrylamide has not been shown to cause cancer in

Answer 19

humans

It was concluded that the although risk of AcA neurotoxicity is negligible, the additional cancer risk may be higher but further studies are needed for confirmation.

Question 20

Acrylamide is rapidly absorbed by

Answer 20

all possible routes, and, due to high solubility in water, distributed all over the organism including milk and placenta.

Question 21

AcA can be regarded as one of the most
important …?

Answer 21

acrylamide

as one of the most important heat-induced contaminants occurring in the bread and bakery products.

Question 22

AcA is formed during

Answer 22

frying, roasting, and baking and is not
typically found in boiled or microwaved foods.

The highest levels are in fried potato products, bread and bakery wares, and coffee.

(acrylamide)

Question 23

what? ranks alongside smoking as a major cause of cancer, WHO says

Answer 23

Processed meat ranks alongside smoking as a major cause of cancer, WHO says

Question 24

pyrolysis

Answer 24

anaerobic decomposition occurring during
incomplete combustion of organic materials, such as wood, coal, or oil, large amounts of various Polycyclic aromatic hydrocarbons are formed.

Question 25

Food can be polluted with PAH either through

Answer 25

athmospheric sediments in gardens or industrial areas, drying of cereal grains by direct contact with combustion gases, at smoking or barbecueing of meat and fish food at open
horizontal coals, at roasting of coffee beans, preparing mate etc.

(Polycyclic aromatic hydrocarbons)

Question 26

Cooking meat at high temperatures and for a long time produces

Answer 26

heterocyclic aromatic amines (HAA)

Question 27

Heterocyclic aromatic amines are predominantly formed at temperatures of

Answer 27

120-250 °C, their formation is inhibited by plant
antioxidants.

Question 28

3 Saturated fatty acids

Answer 28

myristic, stearic and palmitic acids

Question 29

what type fo fatty acid is oleic acid

Answer 29

Monounsaturated

Question 30

Fatty acids can be in organisms and foods as (2)

Answer 30

• in free form
• as derivatives, for example esters

Question 31

PUFAs

Answer 31

Polyunsaturated fatty acids

Question 32

Polyunsaturated fatty acids are, during storage (even at subzero temperatures) and/or thermal processing subjected to three alterations:

Answer 32

autooxidation, thermal oxidation, and thermal polymerisation.

Question 33

Autooxidation of PUFAs proceeds at temperatures below

Answer 33

100°C

• either enzymatically in participation of lipoxygenases, cyclooxygenases and CYP; or
• by a free radical- or a singlet oxygen-mediated mechanism.

Question 34

hydroperoxides, epoxides, and other primary (per)oxidation products are called

Answer 34

called oxylipins

Question 35

Oxylipins can further decompose into toxic secondary oxidation products, such as

Answer 35

alkanes, aldehydes (malonic aldehyde, hydroxynonenal) and ketones, characterized by an unpleasant smell of a spoiled product.

Question 36

CLA is

Answer 36

conjugated linoleic acid

milk, beaf, safflower oil
anticarcinogen,
antioxidant

Question 37

Oxylipins are ubiquitous in

Answer 37

all aerobic organisms

In relation to the organism, OL are divided into endogenous and exogenous.

Question 38

Exogenous oxylipins are consumed with food, particularly with

Answer 38

meat

Question 39

Oxylipins as amphiphilic substances easily cross

Answer 39

biomembranes and, hence, are easily absorbed from GIT and distributed over all tissues and cells.

Question 40

Among the oxylipins are highly toxic linoleic acid oxylipins called

Answer 40

Leukotoxin diols

Question 41

Cellular enrichment with linoleic acid amplifies

Answer 41

PCB-induced disruption (synergism!)

The severe toxicity of PCBs in the presence of linoleic acid may be in part due to the generation
of epoxides and, particularly, their diol metabolites (LTX-diols) of linoleic acid that can
mediate in part the amplified cytotoxicity of the combination of linoleic acid and PCBs to
endothelial cells.

Question 42

Oxylipins, the primary oxidation products of

Answer 42

PUFAs can decompose into secondary oxidation
products – aldehydes (incl. dialdehydes), ketones,
short fatty acids.

Question 43

Oxidation products of cholesterol as a causing factor of

Answer 43

atherosclerosis

Question 44

Free radicals, formed during oxidation of dietary
unsaturated fatty acids oxidize cholesterol into
various

Answer 44

oxy-, keto-, and epoxy-cholesterols.

Several oxidation products of cholesterol have
revealed proatherogenic activity in the
composition of low density lipoproteins (LDL).

Question 45

There is a hypothesis that just oxidized cholesterol assimilated from food is the source of

Answer 45

oxidized lipoproteins in blood,
adverse for health of blood vessels.

Question 46

TFA

Answer 46

Trans fatty acids (TFA)

A trans double bond is a special type of double bond in which the functional groups of the atoms that share the double bond are on the opposite sides of the molecule.

Question 47

The primary dietary TFAs are

Answer 47

vaccenic acid as the major ruminant TFA, and elaidic acid, the main TFA isomer in industrial hydrogenation.

Question 48

The TFA content of industrially hydrogenated fats varies widely and may reach ?% of the total
fatty acid content, whereas the TFA content of beef and dairy products is considerably lower
and accounts only for ?–?% of the fatty acid content.

Answer 48

The TFA content of industrially hydrogenated fats varies widely and may reach 60% of the total
fatty acid content, whereas the TFA content of beef and dairy products is considerably lower
and accounts only for 2–5% of the fatty acid content.

Question 49

Well-known postulate is that lowering LDL cholesterol will reduce the risk of

Answer 49

CHD.
* TFAs, contrarywise, increase LDL and decrease HDL resulting in a worse LDL/HDL ratio…

Question 50

The main dietary sources of trans fatty acids are

Answer 50

cakes, cookies, crackers, margarine, fried potatoes, potato chips, popcorn etc.

Question 51

To meet the recommended dietary intake for fat i.e. amount corresponding to what% of
total calories, most dietary fats should come from sources of what two types of fatty acids.

Answer 51

To meet the recommended dietary intake for fat i.e. amount corresponding to 20 to 35% of
total calories, most dietary fats should come from sources of polyunsaturated and
monounsaturated fatty acids.

Question 52

TFAs can only be formed under heating of the oil at

Answer 52

high temperatures or reusing the oil many
times.

Question 53

60-90% of food-borne (acute) intoxications are caused by

Answer 53

pathogenic bacteria.

Question 54

exotoxins, excreted by bacteria into the environment; are produced mainly by

Answer 54

Gram-positive bacteria. These are mostly very toxic antigenous proteins, becoming activated after a certain latency period.

Question 55

By far the most dangerous bacterial intoxication is

Answer 55

botulism, caused by globular thermolabile proteinous neurotoxin of Clostridium botulinum, a thermostable spore-forming Gram-positive anaerobic bacillus.

Antibotulinum antitoxin (monoclonal antibodies) exists.

Question 56

The spores of Clostridium botulinum are very persistent, but the toxin is destroyed at

Answer 56

85 °C within 5 min. Is stable in acidic stomach.

Question 57

Botulinum toxin is a mixture of seven

Answer 57

neurotoxic proteins that irreversibly block motor nerve terminal at the myoneural junction, preventing releasing of acetylcholinesterase (AChE). The process results in the paralysis of the victim.

Death through the respiratory failure.

Question 58

Intoxications can also be caused by other Gram-positive bacteria like (3)

Answer 58

• Campylobacter „twisted bacterium“ (Campylobacter jejuni),
• Listeria (Listeria monocytogenes), and
• Helicobacter (Helicobacter hepaticus, pylori)…

Question 59

Thermophilic campylobacter is a leading causative factor of

Answer 59

bacterial enteritis (campylobacteriosis)
in humans. Optimal growth temperature 42°C, sensitive to drying and freezing.

Question 60

listeriosis overall mortality rate

Answer 60

high – 20-30%

Question 61

Endotoxins are produced mainly by

Answer 61

Gram-negative bacteria

are complex formations: polysaccharides + lipids, strongly attached to the bacterial cell wall. Relatively thermostable and have latency period.

Question 62

what two bacterial species cause major
part of the food poisonings in the USA.

Answer 62

Salmonellas, over thousand species. Together with Campylobacteria

Question 63

The most severe salmonelloses are caused by (2)

Answer 63

S. enteritidis and S. typhimurium.

Question 64

Biogenic vasoactive amines are (3)

Answer 64

histamine
cadaverine
putrescine

and other similar amines formed during processing and storage of the food.

Question 65

Histamine poisoning occurs, if: (3)

Answer 65

• The regulation mechanism of histamine formation in the body becomes defective.
• Too much of histamine metabolism inhibitors (drugs, ethanol etc.) have been administered.
• Too much histamine has been ingested with food.

Question 66

vasoactive amine cadaverine is formed from

Answer 66

lysine

Question 67

vasoactive amine putrescine is formed from

Answer 67

ornithine

Question 68

vasoactive amine tryptamine is formed from

Answer 68

tryptophan

Question 69

Histamine-rich foods such as

Answer 69

cheese, sausages, sauerkraut, tuna, tomatoes, and alcoholic beverages may contain histamine up to 500 mg/kg.

Question 70

Scombroid fish poisoning

Answer 70

involves Histamine and probably other vasoactive amines emerging after eating of either rotten or bacterially contaminated fish.
Fish may have retained its initial look and smell.

Intoxication develops rapidly – practically immediately or during half an hour, lasts usually for 3 h, but may last for several days.

Question 71

In the histidine-rich fish, the histamine synthesis from histidine starts immediately after

Answer 71

death even earlier than postmortem proteolysis will release additional histidine.

In the case of some fishing techniques, a fish will die before it has been pulled out of water.

Therefore, the concentration of
biogenic vasoactive amines may greatly increase without an appearance of any of the organoleptic indicators of the putrefaction.

Question 72

Putrefaction and bacterial production of ammonia as well as biogenic amines occur especially fast at elevated temperatures, but when a sufficient bacterial population has formed,

Answer 72

the process will continue, although much slower, even at temperatures below 0 °C.

Question 73

urocanic acid syntesized from

Answer 73

histidine by bacteria.
participates in the development of scombroid fish poisoning

Question 74

None of the convenient food processing methods including freezing, canning, or smoking is capable of decomposing the substance or substances causing

Answer 74

scombroid intoxication.

It is much easier to avoid the formation of these agents in fish by cooling as fast as possible, recommendably below 10°C, a storage lasting for more than 4 h must be carried out at 0°C or
lower temperatures.

Question 75

Nitrates and nitrites are “two-faced“ substances, being simultaneosly

Answer 75

both food natural components
and additives.

Question 76

Nitrate ions (NO3-) originate in food from two main sources

Answer 76

1. From garden vegetables containing nitrates as normal physiological constituents.
2. From food additives.

Question 77

Nitrates are not considered to be

Answer 77

hazardous to humans in the actually consumed doses.

Problematic is that nitrates are converted into nitrites by mammal microbial systems.

Question 78

Nitrite ions are acutely

Answer 78

toxic, their LD50 for humans is 22 mg/kg bw, the allowable highest concentration in meat products is 200 ppm, and the ADI value is 0.135 mg/kg.

Question 79

The reduction of nitrates to nitrites already starts in the

Answer 79

mouth, where 8% of food nitrates are reduced by oral bacteria. This process is facilitated by nitrate ions returning to the mouth from the intestines by blood and saliva.

Question 80

Nitrites oxidize hemoglobin to

Answer 80

methemoglobin that is not capable of binding oxygen.

When the methemoglobin concentration in the blood increases to a very high level,
anoxia may appear in the tissues.

Question 81

Nitrites, both those added to meat before canning and those formed during improper storage
of nitrate-rich food commodities, and those that are formed in the mouth from nitrates, produce

Answer 81

N-nitrosamines and N-nitrosamides

in favorable conditions like acidic environment of stomach, or cooking of proteinaceous foods by reaction with secondary amines or amides.

Question 82

Nitroso-compounds formed are efficient

Answer 82

mutagens and rodent carcinogens.

Question 83

what is a surprising fact about nitrite?

Answer 83

nitrite actually has health benefits
* Regulates blood pressure
* Prevents injury from heart attack
* Prevents brain damage following a stroke
* Prevents preeclampsia in pregnant women
* Promotes wound heeling
* Promotes successful organ transplantation
* Treats sickle cell anemia
* Prevents gastric ulcer

Question 84

Food contact materials (FCM) are

Answer 84

all materials and articles intended to come into contact with food, such as packaging and containers, kitchen equipment, cutlery and dishes such as bottles, cans, cartons, knives, forks, cups and plates.

The safety of food contact materials must be evaluated as chemicals can migrate from the
materials into food.

Question 85

Food contact materials cannot – under normal and foreseeable conditions of use – transfer their constituents into foodstuffs in quantities, which could: (3)

Answer 85

• Endanger human health
• Cause an unacceptable change in the composition of the foodstuffs or
• Cause deterioration in the organoleptic characteristics thereof.

Question 86

Bisphenol A is an

Answer 86

endocrine disruptor which can mimic estrogen estradiol and bind to and activate the same estrogen receptor as the natural hormone and cause versatile negative health effects in animal studies.

Early developmental stages are the period of greatest sensitivity to its effects, and studies
have linked prenatal exposure to later physical and neurological difficulties.

Question 87

Bisphenol A can be detected in what percent of the U.S. population?

Answer 87

can be detected in 90 percent of the U.S. population.

US FDA has lately banned the use of BPA in infant formula packaging.
Food is main source of BPA for consumers, thermal paper also potentially significant.

Question 88

Bisphenol A is mainly used in combination with

Answer 88

other chemicals to manufacture plastics and resins.

For example, BPA is used in polycarbonate, a high performance transparent, rigid plastic.

Question 89

Polycarbonate is used to

Answer 89

make food containers, such as returnable beverage bottles, infant feeding (baby) bottles, tableware (plates and mugs) and storage containers.

Question 90

Residues of BPA are also present in

Answer 90

epoxy resins used to make protective coatings and linings for food and beverage cans and vats.

Question 91

EFSA

Answer 91

European Food Safety Authority

Question 92

EFSA’s experts concluded that BPA

Answer 92

poses no health risk to consumers of any age group
(including unborn children, infants and adolescents) at current exposure levels.

But EFSA still recommended tolerable daily intake (TDI) to be lowered 10 times from its previous level of 50 µg/kg bw/ day to 5 µg/kg bw/day.

The Authority also noted that uncertainties remained over a number of other health hazards considered as less likely.

Question 93

Phthalates are

Answer 93

synthetic substances that are used as incorporated into other plastic materials.

Almost 90% is used as plastisizer (softener) in flexible polyvinyl (PVC) products such as plastic bags, food packaging materials and storage tanks, soft toys, intravenous tubes etc

Question 94

Main contact of humans with phthalates is via

Answer 94

food.

Most phthalates, particularly of higher alcohols are lipid-soluble and hence able to concentrate in foodstuffs like butter, margarine or cheese and accumulate in adipose tissues of humans and water organisms.

Lower phthalates do not concentrate in the food chain

Question 95

Two major phthalates of higher alcohols that are used as plastisizers in PVC products are

Answer 95

(2-ethylhexyl) phthalate (DEHP)
& diisononylphthalate (DINP)

Question 96

Residues of DEHP and DINP have been discovered in

Answer 96

fish, water, sediments, they can also bioaccumulate.

Chronic exposure of fish to phthalates may have adverse effects on the health of the humans
eating the fish.

Question 97

Human exposure to the residues of phthalates may also take place by

Answer 97

drinking water,
the dust of floor covering materials (PVC - infant bronchoconstriction),
foodstuffs packaged into PVC-materials, and
blood transfusion when phthalate-containing PVC-bags are used for donor blood collection.