16-mycotoxin Flashcards
what is mycotoxin?
- Molds, which are filamentous fungi, can develop on food commodities and produce various types of chemical toxins, collectively known as mycotoxins .
The main producers of mycotoxins are?
fungal species belonging to the genera Aspergillus, Fusarium , and Penicillin .
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.
25%
- 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?
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).
mold has 2 categories
field fungi
storage fungi
AFB1 ,ZEN,DON
alfatoxin
zearalenone
trichothecenes
alfatoxin and trichothecenes both have feed stuff?
soybean, corn,wheat, braley, sorghum
alfatoxin don’t have ___, trichothecene have
oats
zearalenone don’t hvae__?, but has __?
oats, soybean,
-silage
how many method use to contraol and detoxification?
phy, chem,bio
what does physical method measure?
Grinding and rinsing; Heat treatment; Irradiation degradation; Inorganic absorption
what does chem measure?
Alkalization; Ozone degradation
what does bio measure?
Microbial adsorption; Microbial degradation; Biological degradation
what is the solubility of AFB1?
Soluble in polar organic solvents, such as, Chloroform, methanol, ethanol, propyl alcohol; Poorly soluble in water; Insoluble in petroleum ether, ethyl acetate and hexane
what is the solubility of ZEN?
Insoluble in water; slightly soluble in hexane; progressively more so in benzene, acetonitrile, methylene chloride, methanol, ethanol and acetone;
also soluble in aqueous alkali
what is the solubility of DON?
Easily soluble in water and polar solvents, such as,
methanol, ethanol, acetonitrile, acetone and ethyl acetate; Insoluble in normal hexane and diethyl ether
what is the under pH of AFB1?
Stable in neutral solutions; Resistant to strong acids; Rapid decomposition in alkaline solutions
what is the under pH of ZEN?
Producing fluorescence (group B&G); Destructive for low concentration of AFB1
what is the under pH of DON?
Stable in 200°C; Not decomposed until 268°C; Hard to destroy under normal temperature
what is the under UV light of AFB1?
Stable in neutral and acid environment;
Ester bond will be open in alkaline environment with high concentration and recovered while the concentration decreases
what is the under UV light of ZEN?
Exhibiting blue-green fluorescence (360 nm; More intense green fluorescence (260 nm)
what is the under UV light of DON?
Melting point is 161-16°C;
Hard to destroy under normal cooking
what is the under heat of AFB1?
Sensitive in alkaline environment; Stable in neutral and acid environments;
what is the under heat of ZEN?
Existing absorption peak under short-wave UV light; Decomposed under high tense UV light
what is the under heat of DON?
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
pathway of AFB1
AFB1–>AFBO–> Protein binding which is toxicity
- ->excretion with B1 dialcohol
- ->G in DNA be DNA-adduct–>mutate–> cancer
how alfatoxin affect mammal cell?
carcinogenic
how ZEN affect mammal cell?
estrogenic activity
potential carcinogenica nd teratogenic
how DON affect mammal cell?
cytotoxic
immunosuppressive
Sampling
A mycotoxin-sampling plan is defined by ?
a mycotoxin test procedure and a defined accept/reject limit.
whyTraditional approaches may not be adequate?
since the population could be heterogeneous).
The number of containers sampled can vary from __ in small lots to the __of the total number of containers for large lots
1/4
square root
whyThe whole primary sample must be ground and mixed?
analytical test portion has the same concentration of toxin as the original sample.
LLE
Two immiscible phases are shaken together
Compounds partition to their preferred phase
how to break up complexes
Small amount of water and acidification to break up complexes
e.g of polar solvent
such as methanol, acetone, acetonitrile, ethyl acetate, diethyl ether, toluene, and chloroform.
SPE based on?
molecularly imprinted polymers
SPE can be used for?
Can be used for sample extraction, clean-up and concentration
which method is faster and most popular?
SPE
e.g. of SPE
C-18 (octadecylsilane), silica gel, anionic and cationic exchange materials, immunosorbents and molecular imprinted polymers
(MIPs).
what is IAC
Immunoaffinity columns
the mycotoxins are bound selectively to the___ on the column.
antibodies
A rinsing step removes most of the possible __ and the toxin by ___.
interferences
antibody denaturation.
Offer high ___ and hence they are becoming popular
selectivity
solid phase concentration used to ?
purification of samples which are contaminated with different mycotoxins.
TLC
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.
GC
- -not thermal and volatile stable
- -silylation need to add to be quantified
- -link the system to mass spectrometry MS, flame ionization.
HPLC
- -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
ELISA
based on the ability of a specific antibody to distinguish the three-dimensional structure of a specific mycotoxin.
__is commonly used in mycotoxin analysis.
The direct competitive ELISA
The intensity of the color is __ proportional to the concentration of mycotoxin in the sample
inversely
