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FDSC300 > 16-mycotoxin > Flashcards

16-mycotoxin Flashcards

1
Q

what is mycotoxin?

A
  • Molds, which are filamentous fungi, can develop on food commodities and produce various types of chemical toxins, collectively known as mycotoxins .
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2
Q

The main producers of mycotoxins are?

A

fungal species belonging to the genera Aspergillus, Fusarium , and Penicillin .

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3
Q

The United Nation’s Food and Agriculture Organization estimated that up to __% of the world’s total crops per year are affected with “unacceptable” levels of mycotoxins.

A

25%

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4
Q
  • More than 300 mycotoxins, belonging to various chemical classes, are known. However, the major classes of mycotoxin with a toxicological impact on human health include?
A

1- Aflatoxins (B1, B2, M1, M2, G1, and G2).
2- Ochratoxins (e.g., ochratoxin A, OTA).
3-Trichothecenes (e.g., deoxynivalenol (DON), T2, and HT-2).
4-Fumonisins (FBs, e.g., FB1, FB2, FB3, etc.), and patulin (a mycotoxin that occurs mainly in apples and apple products).
5- Zearalenone (ZEN).

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5
Q

mold has 2 categories

A

field fungi

storage fungi

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6
Q

AFB1 ,ZEN,DON

A

alfatoxin
zearalenone
trichothecenes

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7
Q

alfatoxin and trichothecenes both have feed stuff?

A

soybean, corn,wheat, braley, sorghum

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8
Q

alfatoxin don’t have ___, trichothecene have

A

oats

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9
Q

zearalenone don’t hvae__?, but has __?

A

oats, soybean,

-silage

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10
Q

how many method use to contraol and detoxification?

A

phy, chem,bio

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11
Q

what does physical method measure?

A

Grinding and rinsing; Heat treatment; Irradiation degradation; Inorganic absorption

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12
Q

what does chem measure?

A

Alkalization; Ozone degradation

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13
Q

what does bio measure?

A

Microbial adsorption; Microbial degradation; Biological degradation

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14
Q

what is the solubility of AFB1?

A

Soluble in polar organic solvents, such as, Chloroform, methanol, ethanol, propyl alcohol; Poorly soluble in water; Insoluble in petroleum ether, ethyl acetate and hexane

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15
Q

what is the solubility of ZEN?

A

Insoluble in water; slightly soluble in hexane; progressively more so in benzene, acetonitrile, methylene chloride, methanol, ethanol and acetone;
also soluble in aqueous alkali

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16
Q

what is the solubility of DON?

A

Easily soluble in water and polar solvents, such as,

methanol, ethanol, acetonitrile, acetone and ethyl acetate; Insoluble in normal hexane and diethyl ether

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17
Q

what is the under pH of AFB1?

A

Stable in neutral solutions; Resistant to strong acids; Rapid decomposition in alkaline solutions

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18
Q

what is the under pH of ZEN?

A

Producing fluorescence (group B&G); Destructive for low concentration of AFB1

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19
Q

what is the under pH of DON?

A

Stable in 200°C; Not decomposed until 268°C; Hard to destroy under normal temperature

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20
Q

what is the under UV light of AFB1?

A

Stable in neutral and acid environment;

Ester bond will be open in alkaline environment with high concentration and recovered while the concentration decreases

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21
Q

what is the under UV light of ZEN?

A

Exhibiting blue-green fluorescence (360 nm; More intense green fluorescence (260 nm)

22
Q

what is the under UV light of DON?

A

Melting point is 161-16°C;

Hard to destroy under normal cooking

23
Q

what is the under heat of AFB1?

A

Sensitive in alkaline environment; Stable in neutral and acid environments;

24
Q

what is the under heat of ZEN?

A

Existing absorption peak under short-wave UV light; Decomposed under high tense UV light

25
Q

what is the under heat of DON?

A

Resistant to heat; Stable in 120°C for 1 hour; Decomposed 170°C for 15 minutes under pH=10; Hard to destroy by common cook and heat

26
Q

pathway of AFB1

A

AFB1–>AFBO–> Protein binding which is toxicity

  • ->excretion with B1 dialcohol
  • ->G in DNA be DNA-adduct–>mutate–> cancer
27
Q

how alfatoxin affect mammal cell?

A

carcinogenic

28
Q

how ZEN affect mammal cell?

A

estrogenic activity

potential carcinogenica nd teratogenic

29
Q

how DON affect mammal cell?

A

cytotoxic

immunosuppressive

30
Q

Sampling

 A mycotoxin-sampling plan is defined by ?

A

a mycotoxin test procedure and a defined accept/reject limit.

31
Q

whyTraditional approaches may not be adequate?

A

since the population could be heterogeneous).

32
Q

The number of containers sampled can vary from __ in small lots to the __of the total number of containers for large lots

A

1/4

square root

33
Q

whyThe whole primary sample must be ground and mixed?

A

analytical test portion has the same concentration of toxin as the original sample.

34
Q

LLE

A

Two immiscible phases are shaken together

Compounds partition to their preferred phase

35
Q

how to break up complexes

A

Small amount of water and acidification to break up complexes

36
Q

e.g of polar solvent

A

such as methanol, acetone, acetonitrile, ethyl acetate, diethyl ether, toluene, and chloroform.

37
Q

SPE based on?

A

molecularly imprinted polymers

38
Q

SPE can be used for?

A

Can be used for sample extraction, clean-up and concentration

39
Q

which method is faster and most popular?

A

SPE

40
Q

e.g. of SPE

A

C-18 (octadecylsilane), silica gel, anionic and cationic exchange materials, immunosorbents and molecular imprinted polymers
(MIPs).

41
Q

what is IAC

A

Immunoaffinity columns

42
Q

the mycotoxins are bound selectively to the___ on the column.

A

antibodies

43
Q

A rinsing step removes most of the possible __ and the toxin by ___.

A

interferences

antibody denaturation.

44
Q

Offer high ___ and hence they are becoming popular

A

selectivity

45
Q

solid phase concentration used to ?

A

purification of samples which are contaminated with different mycotoxins.

46
Q

TLC

A

Used for quantitative and semi-quantitative measurements of mycotoxins
 Costs less, is simple and is suitable for rapid screening
 The lack of automation has led to TLC being replaced by
other techniques.

47
Q

GC

A
  • -not thermal and volatile stable
  • -silylation need to add to be quantified
  • -link the system to mass spectrometry MS, flame ionization.
48
Q

HPLC

A
  • -widely and official method
  • -natural fluroscence, sodetected directly by HPLC-fluorescence (HPLC-FD).
  • -MS with electrospray increase sensitivity
  • -0.1-1ug/kg is the limit of HPLC-MS
  • improve limit of detection, coupled to multiple detection automated system
  • expensive, take time adn need expensive equipemnt, cleanup procedure
49
Q

ELISA

A

based on the ability of a specific antibody to distinguish the three-dimensional structure of a specific mycotoxin.

50
Q

__is commonly used in mycotoxin analysis.

A

The direct competitive ELISA

51
Q

The intensity of the color is __ proportional to the concentration of mycotoxin in the sample

A

inversely

FDSC300 (10 decks)

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