Shariful Islam Z Mycntoxin

8/3/2019 Shariful Islam Z Mycntoxin

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Mycotoxins are secondary metabolites produced by microfungi that are capable of

causing disease and death in humans and other animals. Because of their pharmacological

activity, some mycotoxins or mycotoxin derivatives have found use as antibiotics, growthpromotants, and other kinds of drugs; still others have been implicated as chemical

warfare agents. This review focuses on the most important ones associated with human

and veterinary diseases, including aflatoxin, citrinin, ergot akaloids, fumonisins,ochratoxin A, patulin, trichothecenes, and zearalenone.

\Rapid screening of animal feeds for mycotoxins and Salmonella contaminations.

Mycotoxins and Salmonella are described as major and well known safety risks linked to

animal feed and subsequently the human food chain. This chapter considers methods for

the detection of mycotoxins and Salmonella in animal feeds with particular attention torapid methods. Examples of validated methods for mycotoxins are summarised; and rapid

methods for the detection of aflatoxins fumonisins ochratoxins deoxynivalenol andzearalenone are shown.

The following summary of toxins and their targets is adapted from Smith and Moss

(1985), with a few additions from the more recent literature. While this compilation of

effects does not describe the effects from multiple exposures, which could includesynergistic effects, it does give a better idea of possible results of mycotoxin exposure to

multiple molds indoors.

Vascular system (increased vascular fragility, hemorrhage into body tissues, orfrom lung, e. g. , aflatoxin, satratoxin, roridins).

Digestive system (diarrhea, vomiting, intestinal hemorrhage, liver effects, i. e. ,

necrosis, fibrosis: aflatoxin; caustic effects on mucous membranes: T-2 toxin;

anorexia: vomitoxin. Respiratory system: respiratory distress, bleeding from lungs e. g. ,

trichothecenes.

Nervous system, tremors, incoordination, depression, headache, e. g. , tremorgens,trichothecenes.

Cutaneous system : rash, burning sensation sloughing of skin, photosensitization,e. g. , trichothecenes.

Urinary system, nephrotoxicity, e. g. ochratoxin, citrinin.

Reproductive system; infertility, changes in reproductive cycles, e. g. T-2 toxin,

zearalenone.

Immune system: changes or suppression: many mycotoxins.


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Some Common Mycotoxins and the Organisms that Produce Them

Mycotoxin Organism

Acetoxyscirpenediol Fusarium moniliforme, F. equiseti, F. oxysporum, F.culmorum, F. avenaceum, F. roseum, and F. nivale

Acetyldeoxynivalenol Fusarium moniliforme, F. equiseti, F. oxysporum, F.

culmorum, F. avenaceum, F. roseum, and F. nivale

Acetylneosolaniol Fusarium moniliforme, F. equiseti, F. oxysporum, F.


Acetyl T-2 toxin Fusarium moniliforme, F. equiseti, F. oxysporum, F.


Aflatoxin Aspergillus flavus, A. parasiticus

Aflatrem Aspergillus flavus

Altenuic acid Alternaria alternata

Alternariol Alternaria alternata

Austdiol Aspergillus ustus

Austamide Aspergillus ustus

Austocystin Aspergillus ustus

Avenacein +1 Fusarium moniliforme, F. equiseti, F. oxysporum, F.


Beauvericin +2 Fusarium moniliforme, F. equiseti, F. oxysporum, F.


Bentenolide Monographella nivalisBrevianamide Aspergillus ustus

Butenolide Fusarium moniliforme, F. equiseti, F. oxysporum, F.


Calonectrin Fusarium moniliforme, F. equiseti, F. oxysporum, F.culmorum, F. avenaceum, F. roseum, and F. nivale

Chaetoglobosin Chaetomium globosum

Citrinin Aspergillus carneus, A. terreus, Penicillium citrinum, P.

hirsutum, P. verrucosum

Citreoviridin Aspergillus terreus, Penicillium citreoviride

Cochliodinol Chaetomium cochliodes

Crotocin Acremonium crotocinigenum

Cytochalasin E Aspergillus clavatus

Cyclopiazonic acid Aspergillus versicolor


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Aflatoxin

Aflatoxin is one of the most potent carcinogens known to man and has been

linked to a wide variety of human health problems. The FDA has establishedmaximum allowable levels of total aflatoxin in food commodities at 20 parts per

billion. The maximum level for milk products is even lower at 0. 5 parts perbillion. Primarily Aspergillus species fungi produce aflatoxin.

Ochratoxin

Ochratoxin is primarily produced by species of Penicillium and Aspergillus.Ochratoxin is damaging to the kidneys and liver and is also a suspected

carcinogen. There is also evidence that it impairs the immune system.

T-2 Toxin

T-2 Toxin is a tricothecene produced by species of Fusarium and is one of themore deadly toxins. If ingested in sufficient quantity, T-2 toxin can severely

damage the entire digestive tract and cause rapid death due to internal

hemorrhage. T-2 has been implicated in the human diseases alimentary toxic

aleukia and pulmonary hemosiderosis. Damage caused by T-2 toxin is oftenpermanent.

Fumonisin

Fumonisin is a toxin associated with species of Fusarium. Fumonisin is

commonly found in corn and corn-based products, with recent outbreaks of

veterinary mycotoxicosis occurring in Arizona, Indiana, Kentucky, NorthCarolina, South Carolina, Texas and Virginia. The animals most affected were

horses and swine, resulting in dozens of deaths. Fumonisin toxin causes "crazyhorse disease", or leukoencephalomalcia, a liquefaction of the brain. Symptoms

include blindness, head butting and pressing, constant circling and ataxia,

followed by death. Chronic low-level exposure in humans has been linked to

esophageal cancer. The American Association of Veterinary LaboratoryDiagnosticians (AAVLD) advisory levels for fumonisin in horse feed is 5 PPM.

Vomitoxin or Deoxynivalenol(DON)

Vomitoxin, chemically known as Deoxynivalenol, a tricothecene mycotoxin, isproduced by several species of Fusarium. Vomitoxin has been associated withoutbreaks of acute gastrointestinal illness in humans. The FDA advisory level for

vomitoxin for human consumption is 1ppm.

Zearalenone


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New spectroscopic insights for the identification of mycotoxins in cerealsMycotoxins are toxic fungal metabolites that may contaminate primary food productssuch as

cereals, nuts and fruits. The most predominant mycotoxins in Europe among others are

the

Aflatoxins and Ochratoxinsproduced by storage fungis, such asAspergillus andPenicillium

species, and Toxins from field-borneFusarium species, for exampleZearalenone andDeoxynivalenol. [1]

Introduction

Mycotoxins are toxic metabolises produced by fungi, especially by saprophytic moulds

growing on foodstuffs or animal feeds. They must always have been a hazard to man anddomestic animals, but until the past 30 years their effects have been largely overlooked.

Although poisonous mushrooms are carefully avoided, moulds growing on foods havegenerally been considered to cause unaesthetic spoilage, without being dangerous tohealth. Between 1960 and 1970 it was established that some fungal metabolises, now

called mycotoxins, were responsible for animal disease and death. In the decade

following 1970 it became clear that mycotoxins have been the cause of human illness and

death as well, and are still causing it.

Acute mycotoxicoses

Table 1 lists a number of mycotoxins, some of the moulds which are known to produce

them, and known or possible acute diseases with which they may be involved. In some

cases, the connection between mycotoxin and disease is fairly well documented. In other,cause and effect are less certain. The most important disease which may have been due to

mycotoxins, are reviewed briefly below

Chronic mycotoxicoses

Some of the toxins discussed in this section (Table 2) may produce acute effects, but theyare more significant because of their ability to cause long term disease. The best known

and most studied of chronic mycotoxicoses are produced by aflatoxins.

Aflatoxins

Aflatoxins were discovered in 1960 following the deaths of 100,000 young turkeys in

England, and high incidences of liver disease in ducklings in Kenya and hatchery rearedtrout in the United States, English scientists soon established the cause of all these

problems to be toxins produced by the common moulds Aspergillus flavus and A.

parasiticus. Assay techniques were devised and preliminary toxicological studies carriedout by 1963 (Sargent et al., 1963).


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Aflatoxins and primary liver cancer

Scarcely two years after the discovery of aflatoxins came the first warnings that they may

cause human liver cancer. This disease has a high incidence in central Africa and SouthEast Asia. When epidemiological evidence suggested a possible correlation with

mycotoxins in the food supply, field studies were initiated on an international basis.Epidemiological data were coupled with analyses of those foods that form the staple diets

of stable indigenous populations. Stability in both diet and population is essential instudies of this kind because of the long induction period (10-20 years) for human liver

cancer.

Mycotoxins and human health risks an overview

This is a review and brief historical report of mycotoxins as risks to human health.Mycotoxins are recorded in history as far back as 5,000 years ago in China. Besides ergot

and mushroom poisonings, reports as early 1861, indicate that a suspected mycotoxin

affecting humans was reported in Russia, and 1891, there was a report of mouldy rice inJapan to be toxic to man. This review reports on the early literature on mycotoxins

affecting human up to 1960, which is the time of the discovery of aflatoxin, and to our

present knowledge where this problem still persists.

Mycotoxin economic aspects

Thailand is an agricultural country. Agriculture has played a vital role in the Thai

economy contributing around 25% of the gross domestic product (GDP) and about 55%of export by value.

Thailand's economy still depends on the successful export of its major agricultural

commodities. Problems in export of agricultural products are many and varied.

Firstly, it subjects to the uncertainty of the world commodities market including the

importing policy of the buying country.

Sampling, sample handling and preparation in grains

and cereals

SAMPLING

By the result of some sort of a test of a portion of the material with its quality criterion to

judge whether each article is non-defective or defective, or with an acceptability criterion

to judge whether a lot is acceptable or not, the portion of the material in a sample used to


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judge the whole material, improper sampling will lead to inappropriate grading even with

correct testing.

n general, sampling is conducted in such away that the sample represents the population,but in the same case a sample is taken from an especially good or bad section. Without

understanding the sampling method of the test sample, one can not evaluate correctlyabout the quality of the material being inspected.

Uniform sampling

In this method, a sample is taken so as to represent the average of the whole population.

Samples are taken in a small quantity from each section of the population. In this case,

the total amount of the sampling method of the test sample, one cannot of it is used for

testing. Sampling in this case has to be evenly reduced. The reduction procedure is calleddividing, which is performed by quartering, dividing or the use of divider.

Selective sampling

When the products are disposed according to the lowest quality, sampling is made fromsections with particularly poor quality. For example, to judge baking condition of bread

through determination of moisture a sample is taken from the central part of the bread.

Random sampling

This method is applied in cases of the several samples are taken from a product to beuniform and when they do not have the same quality. In this sampling, individual

samples, an amount of sampling, and in some case, sampling period are not fixed before

sampling. Strictly random sampling is rather difficult, and so the subjects of sampling are

chosen by the use of dice, lottery, or random table. The random sampling can preventunfair action of inspect.

AMPLING, SAMPLE HANDLING IN GRAIN AND CEREALS (ISO)

Correct sampling is an operation that requires most careful attention. Emphasis cannot

therefore be too strongly laid on the necessity of obtaining a properly representativesample of grain. Careless or inaccurate sampling could lead to misunderstanding and

unwarranted financial adjustments.

Samples shall be fully representative of the lots from which they are taken. Therefore, as

the composition of the lot is seldom uniform, a sufficient number of increments shall betaken and carefully mixed, thus giving a bulk sample from which are obtained, by

successive divisions, the laboratory samples.

Apparatus

Apparatus is required as follows, and many types and variations of apparatus are

available.


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Prevention and control of mycotoxins

STRATEGIES FOR PREVENTION AND CONTROL OF MYCOTOXINS

To design strategies for the reduction or elimination of mycotoxins, knowledge abouttheir fungal sources are needed. The growth of fungi in crops and agricultural products is

the main cause of toxin formation and related to the concentration of the toxic substances.

Many factors are involved in enhancing the formation of mycotoxins. They are plantsusceptibility to fungi infestation, suitability of fungal substrate, temperate climate,

moisture content and physical damage of seeds due to insects and pests.

Toxin-producing fungi may invade at pre-harvesting period, harvest-time, during post-

harvest handling and in storage. According to the site where fungi infest grains,toxinogenic fungi can be divided into three groups: (a) field fungi; (b) storage fungi; and

(c) advanced deterioration fungi. The first category includes species of plant pathogenic

fungi, namely, genus Fusarium, e.g. F. moniliforme, F roseus, F. tricinctum and F. nivale.The "storage fungi" are principally the general Aspergillius and Penicillium, e.g. A.

flavus and A. parasiticus. The "advanced deterioration fungi" normally do not infest

intact grains but easily attack damaged ones and require high moisure content. Theexamples of the third group are A. clavatus, A. fumigatus, Chaetomium, Scopulariopsis,

Rhizopus, Mucor, and Absidia.

The prevention of mycotoxins in our environment is a big task. In general, prevention of

the contamination of fungi and their mycotoxins in agricultural commodities can bedivided into these following three levels.

1. Primary prevention

The step of prevention should be initially carried out before the fungal infestation and

mycotoxin contamination. This level of prevention is the most important and effectiveplan for reducing fungal growth and mycotoxin production. Several practices have been

recommended to keep the conditions unfavorable for any fungal growth. These include:

development of fungal resistant varieties of growing plants;

control field infection by fungi of planting crops;

making schedule for suitable pre-harvest, harvest and post-harvest;

lowering moisture content of plant seeds, after post harvesting and during storage;

Store commodities at low temperature whenever possible; Using fungicides and preservatives against fungal growth; Control insect infestation in stored bulk grains with approved insecticides.

Table 1: Some mycotoxins, their sources and potential toxicities (1).

Toxins Producing fungi Toxicities


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Aflatoxin Aspergillus flavus Hepatocarcinogen

Aspergillus parasiticus and fatty liver

Citreoviridin Penicillium viridicatum Cardiac beri-beri

Citrinin Penicillium vindicatum Nephrotoxin

Penicillium citrinum

Cyclochlorotine Penicillium islandicum Hepatotoxin

Cytochalasin E Aspergillus clavatus Cytotoxicity

Maltoryzine Aspergillus oryzae

Ochratoxins Aspergillus ochraceus Hepatotoxin

Patulin Penicilliumc-expansum Brain & lung hemmorrhage

Penicillium patulum and carcinogenicity

PR Toxin Penicillium requeforti

Rubratoxin Penicillium rubrum Liver hemmorrhage and fatty

infiltration

Rugulosin Penicillium islandicum Nephrosis & liver damage

Sterigmatocystin Aspergillus flavus Hepatocarcinogen

Aspergillus versicolor

Tremorgens Penicillium and Aspergillus

Trichothecenes Fusarium graminearum Cytotoxicity

Vomitoxin

(Deoxynivalenol)

Fusarium graminearum Vomiting

Zearalenone Fusarium Hyper-estrogenic effect

Secondary prevention

If the invasion of some fungi begins in commodities at early phase, this level of

prevention will then be required. The existing toxigenic-fungi should be eliminated or its

growth to be stopped to prevent further deterioration and mycotoxin contamination.

Several measures are suggested as follows:

Stop growth of infested fungi by re-drying the products;

Removal of contaminated seeds;

Inactivation or detoxification of mycotoxins contaminated;

Protect stored products from any conditions which favour continuing fungalgrowth.


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3. Tertiary prevention

Once the products are heavily infested by toxic fungi, the primary and secondary

preventions would not be then feasible. Any action would not be as effective as thepractices mentioned above, since it will be quite late to completely stop toxic fungi and

reduce their toxin formation. However, some measures should be done to prevent thetransfer of fungi and their health hazardous toxins highly contaminated in products into

our daily foods and environment. For example, peanut oil extracted from poor-gradedpeanut seeds always contains very high levels of aflatoxins and the oil-soluble toxin has

to be eliminated by absorption and alkalinization during oilrefining process. Only a few

practices are recommended:

Complete destruction of the contaminated products; Detoxification or destruction of mycotoxins to the minimal level.

FUNGAL GROWTH INHIBITION

How to prevent growth and invasion of pathogenic fungi in agricultural commodities is

very important in preventing mycotoxin contamination. The inhibition of fungal growthcan be achieved by physical, chemical and biological treatments (17).

Physical treatment. After the crops have been harvested, drying and proper

storage and suitable transportation of the commodities are of prime importance.

Several flavourable factors contribute to the growth of fungi and aflatoxinproduction, namely high moisture content, humid climate, warm temperature

(2540C), insect infestation and pes damage. Many means and measures to

prevention of fungal contamination have been emphasized and practically done.

Drying seeds and commodities to the safe moisture levels (


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cinnamon extract: trans-cinnamic acid, trans-cinnamaldehyde, and ferulic acid

(phydroxy-3-methyl cinnamic acid) (32)

clove oil (32)

other herbs: thyme, star anise seeds (33), black and white peper (34). plumbago

indica (35).

DECONTAMINATION OF MYCOTOXINS

Contaminated mycotoxins in foods and feeds should be removed, inactivated ordetoxified by physical, chemical and biological means depending on the conditions.

However, the treatment has its own limitations, since the treated products should be

healthsafe from the chemicals used and their essential nutritive value should not bedeteriorated. The following methods are suggested to be applied for effective

decontamination of some mycotoxins.

Physically, fungi-contaminated seeds can be removed by hand picking or photoelectric

detecting machines. The method would consume time and Iabor or expensive.

Organic solvents (chloroform, acetone, hexane and methanol) have been used to extractaflatoxins for agricultural products, but mainly in vegetable oil refining process (36).

Heating and cooking under pressure can destroy nearly 70% of aflatoxin in rice compared

to under atmospheric pressure only 50% destroyed (37). Dry and oil roastings can reduceabout 50-70% of aflatoxin B1 (38). We could show that only about 10% of total 1242

ppb of aflatoxin B. decreased in naturally contaminated peanut by heating at upto 100C

(39). Since aflatoxin resists to higher temperature upto 260C, long-time cooking andoverheating would destruct essential vitamins and amino acids in treated foods.

Ionizing radiation such as gamma-rays can stop growth of food spoilage organisms,

including bacteria, molds and yeasts. It also inactivates pathogenic organisms including

parasitic worms and insect pests. It has been reported that gammairradiation (5-10 M-rad)

caused reduction of aflatoxin (40). The irradiation, however, could not completelydestroy the toxin and its mutagenicity. In our laboratory, only about 30% of total 600 ppb

at aflatoxin B1, either pure toxin or in contaminated peanut, was destroyed by 1 and 5

Mrad or gamma irradiation (23). The treatment combination of gamma irradiation andammoniation should be therefore attempted for more aflatoxin decontamination.

Chemical treatment has been used as the most effective means for the removal of

mycotoxins from contaminated commodities. The method should be sure that the

detoxification system is capable of converting the toxin to a nontoxic derivative (s)without deleterious change in the raw product. Mutagenicity of the treated products

should be assessed. The toxicity may be checked by feeding animals including bouts, egg

embryos, chicken, ducklings and rats. Many common chemicals have been brought to testthe effectiveness in detoxification of aflatoxin. These chemicals include the followings:


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acetic acid (C2H5OH) (41)

ammonia gas (NH3) or NH4OH (42,49) or ammonium salts, 3-5% (42)

calcium hydroxide (Ca(OH)2) (43)

formaldehyde (43, 47)

hydrogen peroxide (H2O2 (44)

methylamine (CH3-NH2) (45) ozone gas (03) (46)

phosphoric acid (H3PO4) (47)

phosphine gas (PH3), very highly toxic!

sodium bicarbonate (NaHCO3) (48)

sodium bisulfite (NaHSO3) (49)

sodium bisulfite (NaOH) (48,49)

sodium hypochlorite (NaOCI) (50)

The chemical reactions of detoxification of aflatoxin are primary addition of the double

bond of the furan ring and oxidation involving phenol formation and opening of the

lactone ring. In the presence of acid, aflatoxins B. and G. will be converted into their 2-hydroxy derivatives, aflatoxins B2a respectively.

CONTROL OF MYCOTOXINS

Careful control of mycotoxins should be started and administered by the government of

each country through ministries and organizations such as the Ministry of Health, the

Ministry of Agriculture, Food and Drug Administration, National EnvironmentCommittee Board and Consumer Protection Committee Board. The control program may

be set up by a special administrative committee and the legislative body who regulate the

national policy of food safety and the maximum tolerance limits for mycotoxins.

Farmers, middlemen, food and feed factories and exporters will be well educated aboutmycotoxins and encouraged to prevent and control the contamination of microflora and

their health-hazardous mycotoxins in their commodities as much as possible.

International cooperation for the mycotoxin regulation in trading products orcommodities is also needed. The countries should establish quality control limits for

certain commodities intended for export or import. The producer countries would be

stimulated to be aware of mycotoxin contamination in their exported susceptiblecommodities. For example, the European Economic Community (EEC) has already

established certain maximum tolerance limits of aflatoxins for animal feeds, i.e. not more

than 20 ppb for complete feed for gigs, poultry and feed supplements for dairy animal; 50

ppb for produce to be processed into mixed feed and complete feed for cattle, sheep andgoats.

International organizations such as FAO, WHO and UNEP in the UN system are engaged

in providing essential information on various aspects of prevention and control of

mycotoxin problems to all the countries. Guidelines for international trade include: a)procedure of sampling and analysis, b) surveillance and food control inspection systems,

c) use of contaminated produce in feeding of different animals, d) protocols for


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detoxification and the quality control of the products. Conferences, symposiums,

trainings and workshops on current informations of mycotoxins should be promoted.

Low-cost technology for assessment, prevention and control of environmentalmycotoxins could be then transferred from developed countries to developing ones.

Aflatoxin this mycotoxin primary semilar

Fusarinun is a nonsteroidan estrogenic

Mold can contain toxigenic alements and some similar


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The most significant species ofmycotoxin producing fugi that

have an similar

Efficiency in all animal species

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Shariful Islam Z Mycntoxin