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Name: Praveen Kumar

Id no.: 14AG63R21

Native place: PATNA , BIHAR

Email: PRAVINKUMAR881@HOTMAIL.COM

Education: B. TECH ( MECHANICAL ENGG)

University of graduation: KIIT UNIVERSITY

Year of passing out: 2012

Job experience (if any):NA

Training/projects undergone: BIHAR STATE

HYDROELECTRIC CORPORATION

Seminar on: BIODETERIOTATION OF

GRAINS AND RISK OF MYCOTOXINS .

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Relevant information about mycotoxins and their

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The Bio deterioration of grains and the risk of mycotoxins

Praveen Kumar14AG63R21

Department of Agricultural & Food EngineeringIIT Kharagpur

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Contents

– Bio deterioration of grains.

– Molds and mycotoxins.

– The significance of mycotoxins.

– The interaction of mycotoxins.

– The control of mycotoxins .

– The segregation of contaminated grains .

– Sampling and analysis .

– Conclusions .

– References .

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• The condition of stored grains is determined by a complex

interaction between grain and the variety of macro and

micro organisms.

• Insects , mites , rodents birds and microorganisms which

may attack it .

• Grains provide an abundant source of nutrients and the

natural consequence is the spoilage of the grains caused by

organisms.4

Bio deterioration of grains

• The extent of contamination by moulds is largely

determined by the temperature of the grain and the

availability of water and oxygen.

• The interaction between grain temperature and moisture

content also affects the extent of mould colonisation.

• Insects and mites (arthropods) can, of course, make a

significant contribution towards the bio deterioration of

grain, through the physical damage and nutrient losses

caused by their activity.

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Bio deterioration of grains

• In general, grain is not infested by insects below a

temperature of 17°C whereas mite infestations can occur

between 3 and 30°C and above 12 per cent moisture content .

• The metabolic activity of insects and mites causes an increase

in both the moisture content and temperature of the infested

grain.

• Arthropods also act as carriers of mould spores and their

faecal material can be utilised as a food source by moulds.

Furthermore, moulds can provide food for insects and mites

but, in some cases, may also act as pathogens. 6

• Another important factor that can affect mould

growth is the proportion of broken kernels in a

consignment of grain.

• Mould growth is also regulated by the

proportions of oxygen, nitrogen and carbon

dioxide in the intergranular atmosphere.

• Many moulds will grow at very low oxygen

concentrations; a half of linear growth,

Interactions between the gases and the prevailing

water activity also influence mould growth

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Moulds and mycotoxins

• In ecosystem the growth of micro organisms is due

to the nutrient availability and micro

environmental changes with time.

• Grains are predominantly contaminated by those

moulds requiring high water activities (at least 0.88

aw) for growth.

• Stored grains will support moulds which grow at

lower moisture levels.8

• The rate of mould growth is also determined by the ability

of the micro-organism to compete with other species.

• Some species, including those of Aspergillus, Penicillium

and Fusarium, can occur both in the field and in storage.

• Some secondary metabolites produced by moulds are

highly toxic to animals, humans and plants. These so-called

are 'mycotoxins'.

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Mycotoxins

• Mycotoxins are the metabolites ( by – product ) of the growth

of moulds.

• They have very real toxic side effects to other plants and

animals.

• They are also generally less selective of the hosts they attack

and can cross plant species .

• Fusarium , Penicillium and, Aspergillus are the most important

mycotoxins producing fungal genera .

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• They are low molecular weight compounds with diversechemical structures and biological properties.

• Toxigenic (mycotoxins-producing) Aspergillus moulds can occurboth before and after harvest.

• Fusarium and Penicillium moulds occur predominantly beforeand after harvest .

• Aspergillus is associated with the tropics and Penicillium withtemperate climates, Fusarium moulds occur world wide.

• Temperature and moisture can greatly affect the growth rateof fungi as well as the types and amount of mycotoxinsproduced.

The major mould and mycotoxinsMould species Mycotoxins produced

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Aspergillus parasiticus Aflatoxins B1, B2, G1, G2

A. Flavus Aflatoxins B1, B2

Fusarium sporotrichioides T-2 toxin

F. Graminearum deoxynivalenol (vomitoxin)Zearalenone

F. Moniliforme fumonisins

Penicillium verrucosum ochratoxin A

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The significance of mycotoxins• The significance of mycotoxins is difficult to asses due to

extremely small amount of toxic chemical in the diet .

• There are several risks of mycotoxins ,these are :

• Risk to human health.

• Their effect on animal health .

• Impact on livestock production and productivity

• Legislation ( when it exists) .

• Demand of the food industry of for high quality rawmaterials.

• Mycotoxins are not easily detectable , when health problemsarise all possible involvement are investigated and then afterwhen no symptoms are found then only mycotoxins aretested.

• The existence of legislation requires an agreed policy fortesting and control to be implemented , at present there is nolimit for mycotoxins in raw cereals .

• However , regulations are to be introduced in 2 to 3 years forAflatoxins and ochratoxin A in raw cereals .

• The mycotoxins have attracted worldwide attention, over thepast 30 years.

• Firstly because of their perceived impact on human health.

• Secondly, economic losses occurring from condemnedfoods/feeds and decreased animal productivity.

• Thirdly, serious impact of mycotoxins contamination oninternationally traded commodities.

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The Aflatoxins• Aflatoxins are group of mycotoxins produced by Aspergillus ,

mainly A. parasiticus and A.flavus .

• They are common fungal contaminants of nuts but are also found in many other feedstuffs e.g. corn , tree nuts , rice and wheat.

• Aflatoxins B1 , B2, G1 and G2 are four naturally occurring forms of Aflatoxins , B1 being the most potent prevalent .

• Chemical structure of Aflatoxins.

The Ochratoxins

• The ochratoxins are produced by numerous Aspergillus andPenicillium supplement , including A.ochraceus andPenicillium verrucosum.

• Ochratoxins are found principally in cereal grains but also inanimal by-products because of their binding with plasmaproteins and long half life in animal tissues .

• There are four ochratoxins homologues : A, B , C and D. A isthe most prevalent whereas , A & C are most toxic .

• Chemical structure of Ochratoxins.

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Tremor genic mycotoxins

• Tremor genic mycotoxins are produced by Penicillium ,Aspergillus , and claviceps .

• They are rarely found in feed ingredients but are usuallyproduced during food spoilage .

• Dogs are exposed to tremor genic mycotoxins when eatingmouldy garbage ,such as dairy product , nuts , grains.

• More than 20 mycotoxins have been classified as tremor gens.

• Most tremor genic mycotoxins are neurotoxic indole alkaloids.

• Penitrem A causes slight salivation , vomiting , ataxia andtremors in dogs .

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The interaction of mycotoxins • The complex ecology of mould growth and mycotoxin

production can produce mixtures of mycotoxins in food andfeed grains, particularly in cereal .

• The co-occurrence of mycotoxins can arise through a singlemould producing more than one toxin.

• The co-occurrence of mycotoxins can affect both the level ofmycotoxin production and the toxicology of the contaminatedgrain.

• The presence of trichothecenes may increase the productionof Aflatoxins in stored grain .

• To date, little is known about this particularly important areaof mycotoxicology.

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The control of mycotoxins• Since the occurrence of mycotoxins is a consequence of bio

deterioration, to mitigate the effect of spoilage the agents liketemperature, moisture and pests should be controlled.

• Humid climate ,excess rainfall and moist weather lead tomould contamination and mycotoxin production in grains.

• Considerable effort has been expended on the developmentof crop strains which are resistant to mould growth ormycotoxin production.

• Breeding programmes have focused, for example, on thedevelopment of Aspergillus/Aflatoxins resistant varieties ofmaize and groundnuts, with limited success.

• However, despite the best efforts of the agriculturalcommunity, mycotoxins will continue to be present in a widerange of foods and feeds.

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The Segregation of Contaminated Grains• There are basically two methods of controlling mycotoxins:

• The segregation of contaminated grains and,

• The Detoxification of Mycotoxins.

The segregation of contaminated grains :

• The identification and segregation of contaminatedconsignments is pursued through the implementation ofquality control .

• The consignment is accepted or rejected on the basis of theanalysis of representative samples of the food or feed.

• Acceptable levels of mycotoxin contamination are specified byindividual customers, commercial agreements and regulators .

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• The mycotoxin content of grains can be further reducedduring processing.

• Automatic colour sorting, often in combination with manualsorting, is widely used to segregate kernels of abnormalappearance during the processing of edible grade groundnuts.

• Mycotoxins can also be concentrated in various fractionsproduced during the milling process.

• Zearalenone and deoxynivalenol, for example, are reportedlyconcentrated in the bran fraction during the milling of cereals.

• the stability of mycotoxins during processing will dependupon a number of factors including grain type, level ofcontamination, moisture content, temperature and otherprocessing agents.

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The Detoxification of Mycotoxins

• Ammonia, as both an anhydrous vapour and an aqueoussolution, is the detoxification reagent, for the destruction ofAflatoxins.

• The nature of the reaction products of the ammonisation ofaflatoxin is still poorly understood.

• The formal approval of the ammonisation process by the USAFood and Drug Administration is still awaited.

• Commercial processes have not been developed for thedetoxification mycotoxins.

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Sampling and analysis.

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• The control of the mycotoxin problem comprises :

• The identification of the nature and extent of the problem bythe implementation of surveillance studies .

• The regular monitoring of foods and feeds as part of a qualitycontrol programme.

• The introduction of improved handling procedures, whichaddress the identified problems.

• The distribution of aflatoxins (and, presumably, othermycotoxins) in grains is highly skewed, it is important thatgreat care is taken to collect a representative sample .

Conclusions.

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• The mycotoxins described in this chapter, as symptoms of biodeterioration, are acutely toxic, carcinogenic,immunosuppressive and oestrogenic.

• The potential immunosuppressive role of mycotoxins in theaetiology of human disease is an especially important issuewhich requires further careful study.

• Every effort must be made to minimise the occurrence ofmycotoxins in food and feed grains.

• Undoubtedly, the implementation of improved handling andquality control procedures will have a significant effect on theincidence of mycotoxins in important foods and feedsthroughout the world.

References

• Maxwell C K Leung, Gabriel Diaz – Llano, and Trevor K. smith. Department of animal and poultry science, university of Guelph, Guelph, Ontario, Canada.

• Naresh magan, David aldred, applied mycology group carnfield health, Carnfield University, silsoe campus, Bedford.

• K .A . Scudamore , KAS mycotoxins , 6 fern drive , Taplow maidenhead , Berkshire .

• Black, Kevin. “Aflatoxins in Corn” (Dec. 1996) Online. Internet. 20, February , 1997.

• Cheeke, Peter R., Lee R. Shull. ed. Natural Toxicants in Feeds and Poisonous Plants. Westport: AVI Publishing 1988

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Thank you