Mycotoxins are toxic chemicals produced by fungi that can contaminate food crops. Over 300 mycotoxins are known but the major ones that affect food include aflatoxins, fusarium toxins, ochratoxins, and patulin. Mycotoxins are carcinogenic and cause health issues in humans and livestock. Proper management throughout cultivation, harvest, storage, and processing is needed to minimize mycotoxin contamination of crops like peanuts, maize, and wheat. Pre-harvest practices like timing, weeding, and post-harvest practices like drying and shelling can reduce aflatoxin levels in peanuts.

1. MYCOTOXIN CONTAMINATION IN FOOD
CROPS AND IT’S MANAGEMENT
RAKESH BELLUDI
L-2017-A-137-M

3. What are mycotoxins?
 Secondary metabolites (chemicals) of a fungus, that produce
toxic results in another organism and cause mycotoxicosis in
animals and humans
They are cytotoxic disrupt cell structures such as cell
membranes and processes such as protein, DNA and RNA
synthesis
Ayalew (2010)

4. How was the concept of mycotoxins developed ?
In 1960s an outbreak of a disease known as Turkey X
It was due to mycotoxin contaminated peanut feed meal
Today we call it as aflatoxin, a class I carcinogen
Wayne (2012)

5. Other reports of mycotoxicosis
Alimentary toxic aleukia (fusarium) killed over one lakh
people
 Stachybotryotoxicosis (starchybotrys) killed thousands of
horse
In 2004, 125 people died due to consumption of
homegrown maize with toxin in kenya
Six lakh people die every year due to chronic poisoning of
mycotoxins
One out of four, liver diseases are from mycotoxins
(Samuel and Adeyeye 2016)

6. Why mycotoxins were produced?
The reason for production is not yet known but they are
necessary for the growth and development of the fungi
These are the toxic low molecular weight, secondary
metabolites produce by the fungi .
(Howlett 2008)

7. How many mycotoxins are there?
 Today 300 - 400 mycotoxins are known, but few
are important as concerned to effects on animals
and humans

8. Aflatoxin
Mycotoxins
DON
Fumonisin
Zearalenone T-2 Toxin
Ochratoxin
Patulin Ergot

9. Mycotoxins on food crops

10. Some important mycotoxins

11.  There are more than 100 species of aspergillus but only 50 of
them produces mycotoxins
In 1961, caused the deaths of over 1,00,000 turkeys “Turkey
X disease”
 Grows best between 26-32 C°.
Aflatoxins
Cotton, peanut, maize, spices, pistachios.
Fengyuan (2018)

12. Major sources are maize and peanut
Factors favorable for production i) Temperature
ii) Grain moisture
Aflatoxin is carcinogenic and majorly produced by
i) Aspergillus flavus
ii) Aspergillus parasiticus
iii) Aspergillus nomius
Aflatoxins

13. Types of Aflatoxins
 Naturally produced Aflatoxins-B1, B2, G1, G2.
They undergo modifications during cellular metabolism and
processing of foods to produce several derivatives such as M1,
M2, P1, etc.
International limit 15µg per kg food
(Yin, 2008)

14. Aflatoxin B-1, most potent aflatoxin
It selectively targets human gene p53, described as
“Guardian of the genome”
In milk for human consumption, advisory level is 5 ppb
Types of Aflatoxins
Yamakuchi (2009)

15. Aflatoxin Effects
 Inhibits protein synthesis
 Liver damage
 Susceptibility to other infections
 Carcinogenicity
Yamakuchi (2009)

16. Uses of Aspergillus
Aspergillus niger is used to make artificial citric acid, one
used in soft drinks
Miso, soya sauce and sake prepared by strains of Aspergillus
oryzae

17. Fusarium Toxins
• They are produced by over 50 species of fusarium
• They produce toxins like i) Fumonisins
ii) Deoxynivalenol
iii) Zearalenone
iv) T-2 toxin
Maize, wheat, barley, beans.
Gupta (2017)

18. Fusarium graminearum in wheat causes scab damage to kernels
and fusarium head blight
Which produces deoxynivalenol (DON), also called vomitotoxin
 Trichothecene also produced by this, which acts on circulatory
and nervous system
Fusarium Toxins
Kana (2013)

19.  Fusarium graminearum in maize
 Produces toxins: DON, Zearalenone
and T-2 toxin
T-2 toxin
Zearalenone
Kana (2013)

20.  Fusarium moniliforme in corn causes fusarium ear rot
 Which produce toxin called fumonisins that cause blind
staggers in horse
 In animals cause diseases like
i) Bone malformation in chicks and pigs
ii) Esophageal cancer in humans.
iii) ‘‘Crazy horse disease’’ in horse
Other toxins produced include fusaric acid, fusarins
 Advisory levels are 5 ppm in animal feed
Crazy horse disease
Marasas (1988)

21. Alimentary Toxic Aleukia (ATA)
• During World War II, in Soviet Union, corn grain left to over-winter
becomes contaminated with T-2 toxin
• Severe mycotoxicosis lead to burning in the mouth, esophagus,
tongue & stomach
• Bone marrow formation is halted & anemia develops. Hemorrhage
of nose, gums, mouth and stomach occurs

22. Ergot toxicosis
 Ergot is a toxic mixture of alkaloids in the sclerotia of species of
claviceps
 It is the common pathogen of various grass species and cereals
 It is the earliest recorded example of mycotoxicosis and called
St.Anthony’s fire or Ignis Sacer
Bennet (2018)

23. The most prominent fungus is claviceps purpurea in Rye.
It cause ergotism in humans and other mammals
C. purpurea has at least 3 races, G1,G2 and G3 of which G1 is
common on rye ,Toxins produced are ergotamine and ergometrine
Sylvie (2006)

24. Ergot poisoning symptoms
Animal symptoms
• Dry gangrene
• Internal bleeding
• Vomiting
• Constipation
Human symptoms
• Gastrointestinal stress
• Gangrene of extremities
of hands & feets
• Fetal abortion
• Extreme burning and
Cold sensations
Rye, barley, sorghum, millets, wheat and wild
grasses
Ergot alkaloids have been used pharmaceutically Ashiq (2015)

25. Patulin toxins
• It is a toxin produced by Penicillium, Aspergillus and Paecilomyces
• Penicillium expansum is associated with the range of moldy fruits
and vegetables

26. Patulin has not shown to be carcinogenic but it has been reported to
damage immune system in animals
Other species of Penicillium produces citreoviridin, citrinin
and luteoskyrin commonly known as yellowed-rice toxins
Moss (2008)

27. Ochratoxins
Ochratoxins are produced from
Aspergillus and Penicillium
species
It occurs in three secondary
metabolite form OTA,OTB and
OTC on peanut, beans and dried
fruits
Aspergillus ochraceus is a wide
contaminant of beer and wines
 Orchratoxin has been labelled as a
carcinogen and a nephrotoxin
Ochratoxin b is a chlorinated form of OTA
Ochratoxin c is an ethyl ester form of OTA
Ochratoxin AAshiq 2015

28. Physical
Chemical
Biological
Environmental conditions like
temperature, relative humidity and
insect damage
Use of fungicides and
fertilizers
Interaction between
colonizing fungi and
susceptible crop
Which are the factors affecting mycotoxin
production?

29. Mycotoxin Temperature (°c) Water activity
Aflatoxin 33 0.99
Ochratoxin 25-30 0.98
Fumonisin 15-30 0.9-0.995
Zearalenone 25 0.96
Deoxynivalenole 26-30 0.995
Citrinin 20-30 0.75-0.85
Optimum temperature for mycotoxin production
Mannaa (2017)

30. • Mycotoxins occur in field conditions before harvest
• In post harvest conditions like processing,
packaging, distribution and storage
When does they occur?
Mannaa (2017)

31. Mycotoxin chain of events

32. How does they spreads?
The spores of these fungi spreads by wind
Transmitted by insects
Via transportation mechanisms like trucks and crop machinery

34. Toxicity of mycotoxins
Acute toxicity
Chronic toxicity
Teratogenic toxicity
Mutagenic toxicity

35. Acute toxicity
• It occurs either by
single or multiple
exposures
• Deterioration of
liver and kidney
• Inference with
protein synthesis
• Necrosis of skin
Sandova (2017)

36. Chronic toxicity
As a result of long term exposure to the to mycotoxins
Induction of cancer
Induction of tumors
Sandova (2017)

37. Mutagenic and teratogenic effect
• Replication of DNA is affected by producing mutagenic and
teratogenic
Sandova (2017)

38. How to detect mycotoxins?
Mycotoxins are commonly detected and quantified using
antibody-based assays and chromatography techniques.
Enzyme-Linked Immunosorbent Assay (ELISA) is an
antibody-based assay that is commonly used to detect
mycotoxins
A number of commercial ELISA kits are available for
different mycotoxins, but they detect only upto 0.2ppm

39. • High-Performance Liquid Chromatography (HPLC) and Gas
Chromatography/Mass Spectrometry (GC/MS) are most widely
used methods for mycotoxin detection and quantification
• They can detect less than 0.05ppm

40. Management of mycotoxins

41. What is the importance of mycotoxin
management ?
• To minimize:
Qualitative and quantitative losses
Financial losses and safeguard trade
• One billion metric tons of food loss occur every year
Gary (2018)

42. But why we are facing mycotoxin problems?
Due to poor or absence of :
pre and post harvest technologies
improved processing machineries and methods
market facilities
awareness

43. What are the impacts of poor management?
Post harvest losses
Health problems from consumption of unsafe food
(cancer, child stunting, blood and nerve defects, instant death)
Rejection of food commodities which have higher than
permitted limits of mycotoxins

44. Aflatoxin Management in Groundnut

45. How crops get contaminated?
• Prolonged exposure to a high-humidity environment
• Damage from stressful conditions such as drought
• The entry for these aflatoxin-producing fungi could be at
any/all of these three stages:
• Pre-harvest entry of fungus (during plant growth).
• Entry of fungus during harvest.
• Postharvest entry of fungus (after harvest and during
processing).
ICRISAT 2016

46. How to reduce aflatoxin contamination?
Pre Harvest Practices
• Early planting
• Maintaining field hygiene
• Timely weeding
• Termite

47. • Harvesting of water in the field
• Avoid Drought conditions
• Retain moisture in fields
• Use of tied ridges (box ridges)
• Mulching also retain water in the field
• Soil amendments
Apply lime to the crop for strong shells (pod resistance)
Pre Harvest Practices
ICRISAT 2016

48. • Harvesting at the right stage
• Avoid harvesting when kernels are premature
• Harvest crop when fully mature, this will minimize
the exposure of the crop to extreme heat, sudden rain
or drought, which also influence infection
During Harvesting
ICRISAT 2016

49. • Avoiding injuries to pods
• Removal of soil
• avoid carrying the fungus
into stores and processing
facilities.
During Harvesting

50. • Proper drying
• Drying on roof or on soil leads
to the absorption of moisture
and supports fungal growth that
leads to aflatoxin contamination
• Use of Mandela Corks
(ventilated stacking)
After Harvest
At the household level
ICRISAT 2016

51. • Proper shelling
• Avoid Sprinkling water on
pods to shell
• Use of mechanical shellers
• Grading and sorting
• Proper storage
At the household level
After Harvest
ICRISAT 2016

52. • Sorting before shelling
• Reject Loose shelled kernels,
shrivelled, damaged or
discolored pods
• Grading after shelling
At the Processor’s level
After Harvest

53. Biocontrol Strateries
Competative atoxigenic fungal technology (CAFT)
 Deploying of atoxigenic aspergillus strains shown to reduce
level of aflatoxins
This breakthrough technology reduces aflatoxins during
crop development, post-harvest storage, and throughout the
value chain
Even when the conditions are favorable
Provide multiyear benefits
Unable to mate with the toxigenic forms shown by SSR
profiling and VCG (vegetative compatibility grouping)
studies
Used in peanut, maize, cottonseed, chilli, etc.
Ortega (2018)

54. Aflasafe treatment

55. Case study
• In 2017, 95% reduction ( below 5ppm) of the aflatoxin in
groundnut in Ghana
Ortega (2018)

56. What are the drawbacks of CAFT
It posses potential challenges since it does not offer protection
from exponential mold growth, leads to poor quality and
hygiene.
However, development of varieties with desirable genetic
resistance to pre harvest infection is needed
So there arises a concept of double defence line system .
(Bhatnagar et al 2015)

57. What is double defence line ?
• It is the host plant resistance strategy to improve genetic
resistance.
• It involves the inhibition of aflatoxin production in scenarios
where fungal infection is difficult to eradicate.
it alters the interaction between fungal and plant pathosystems.
by
i) By producing defensins
ii) By HIGS- Host induced gene silencing

58.  Activation of defence pathways by overexpressing (OE)
antifungal plant defensins MsDef1 and MtDef4.2, from
Medicago sativa and M. truncatula respectively.
 Host-induced gene silencing (HIGS) of aflM and aflP genes from
the aflatoxin biosynthetic pathway.
 This was first done in variety JL24. Sharma (2018)

59. Case study
After 3 days of inoculation. Immune with ≤1ppm,
susceptible over 3000ppm of mycotoxin
Sharma K K (2018)

60. Aflatoxin Management in Maize

61. How to reduce aflatoxin contamination?
Pre Harvest Management
• Pest management techniques
• Reduce the entry points for the fungus
• Biocontrol
• the non-toxigenic vs toxigenic forms
• carefully select non-toxigenic strains to eliminate the
toxic relative effectively

62. • Proper harvesting
• Avoid drying of cobs in the field on bare
• Dry on polyethylene sheets
• Grading cobs
• Damaged cobs should not be mixed with healthy
ones to reduce spread of spores
• Winnowing, washing before cooking, and dehulling
of maize grains reduce aflatoxin and other
mycotoxins
During Harvesting
Bankole (2003)

63. • Sanitation
• Clear the remains of previous harvests
• Destroy infected crop residue
• Clean the stores before storing the new harvest
• Proper storage
• Do not heap cobs in stores
• Pack them in a clean, sealed container to avoid
exposure to excessive moisture and humidity.
After Harvest

64. Mycotoxin Maximum limit permitted in µg/kg
Aflatoxin 10 -15
Deoxynivalenol 750
Zearalenone 1000
Ochratoxin A 5
Fumonisin 1000
(FAO, 2004)
Legislative controls for mycotoxins

65. Future challenges
Development of mycotoxin resistant varieties
RNAi technologies in major crops

66. CONCLUSION
• Safeguarding human and animal health is the goal of
mycotoxin research.
• To accomplish this goal, we must not only understand the
chemistry and toxicology of mycotoxins, but we must also be
able to understand why some plant pathogenic fungi produce
them.
• Regulatory control,fast and effective analysis of mycotoxins
will serve to reduce the toxin contamination