# Background to climate change issues. # Impact of temperature, water availability, and CO2 on mycotoxin production # Prediction strategies. # Trends in mycotoxin occurrence.

1. Climate Change and
Mycotoxins
Ph. D. Student
Atheer Jasim Mohammed
May, 2017

2. Contents of my talk
 Background to climate change issues.
 Impact of temperature, water availability, and CO2
on mycotoxin production
 Prediction strategies.
 Trends in mycotoxin occurrence.

3. Background and Facts
 Some toxic low molecular weight compounds produced by
filamentous fungi are referred to as mycotoxins and which
contaminate food and feeds (Table 1).
 Regulations minimizing human exposure to mycotoxins.
 Several health problems and death have occurred from
mycotoxin consumption.
 Many factors involved in mycotoxin contamination in
environments (Fig. 1).
 Production of mycotoxins, for example, on crops, is highly
influencing to environmental factors [e.g. temperature
(Table 2) and available moisture (Table 3)] and pre-
postharvest.
 When climate change occurs, mycotoxins will be affected.

4. Large-scale clearing of forests, burning of fossil fuel,
and other human activities have changed the global
climate.
Concentrations of methane, carbon dioxide, nitrous
oxide, and chlorofluorocarbons in the atmosphere have
increasing of environmental warming.
The life cycle of all microorganisms, including
mycotoxigenic molds, depends on two main factors:
water availability and temperature. These factors
interact to influence a series of parameters including
germination, growth, sporulation, and mycotoxin
production.
Background and Facts

6. Fig. 1. Factors affecting mycotoxin occurrence in the food chain

7. Impact of temperature, water availability, and CO2 on
mycotoxin production
 Increasing of temperature and water availability on both
fungal growth rates will be predicted effects on the production
of some most relevant mycotoxins: Alternaria toxins,
fumonisins, trichothecenes, ochratoxin A, aflatoxin B1 and
patulin.
 Typically, high concentrations of mycotoxins in grains depend
on the number of rainy days and days with relative humidity
above 75%, but there can be a decrease in mycotoxin
concentrations at temperatures below 12 or above 32 °C.
 Aspergillus flavus and A. parasiticus, the main aflatoxin
producers, are xerophilic fungi which thrive under higher
temperatures and lower rainfall or water availability.

8.  Fumonisin occurrence in drought climates. Dry season maize in
Southern and Eastern Africa may contain high levels of this toxin,
even if the maize appears to be of very good quality.
 Fumonsins are less significant in northern temperate zones with
cooler climates. High temperatures favor the growth of the
fumonisin producer Fusarium verticillioides, which means that a
warming trend lead to greater reproduction.
 Chakraborty et al. (2011) have shown that an increase in atmospheric
CO2 concentration will directly increase the amounts of Fusarium.
 In developing countries, drought climates may play an important role
in terms of food security. Maize, peanuts, and pistachios are
particularly prone to infection during heat/drought stress due to
cracking or splitting, which may result in a significant increase in A.
flavus and aflatoxin contamination.

9.  The effects of humidity on mycotoxin production in
crops are less moderate than those for temperature.
Drought /rainfall patterns: total annual rainfall patterns may shift and
interact with temp. & CO2 changes (2016)

10. 1.00
0.90
0.80
0.70
0.60
0 10 403020 50
Temperature (oC)
Wateractivity(aw)
Fusarium/Alternaria
species
Penicillium
spp.
Aspergillus spp.
Diagrammatic profiles of growth/no growth limits for the
three mycotoxigenic genera

11. Climate change:
important factors to
consider
 Water stress (water activity, aw)
 Temperature fluctuations
 CO2
Very limited data if any on
mycotoxigenic pathogens

12. Climate change can affect crop diseases:
what impacts on mycotoxin production?
Crop
(resistance)
Pathogen
(changing population)
Environment
(changing climate)
Pre- and Post-harvest
spoilage & Mycotoxin

13. Our focus has been in mycotoxins – why?
 Mycotoxins - naturally occurring toxic secondary
metabolites.
 heat stable/difficult to destroy even during processing.
 Produced by Aspergillus, Penicillium, Fusarium and
Alternaria genera.
 Contaminated at any time: field, harvesting, drying,
transport and storage, milling and in finished products.
 Low mould counts do not mean that food is free of
mycotoxins, as moulds can die but the toxins will
remain.

14. ochratoxins
Fumonisins
AflatoxinsTrichothecenes
Raw materials, moulds and mycotoxins

15. Commodities for which EU legislative limits exist
Aflatoxin OTA Patulin Fusarium toxins
_______ ______ _______ _______
Groundnuts + +
Nuts + +
Dried fruit + +
Cereals + + +
Maize + + +
Spices + +
Baby foods + + + +
Coffee +
Cocoa +
Grape juice +
Fruit + + + ( apple )
Milk, egg +
Wine +

16. Climate change impacts on mycotoxins: directly
and indirectly ?
 Increased plant diseases/pest reproduction and interaction with
plants? YES
 Effects on biodiversity of microbiota on plant surfaces? YES
 Will this lead to more mycotoxin contamination of staple crops ???
 Will different mycotoxins become important on a regional basis ???
 Will this make existing legislation out of step with potential
problems ???
 EU borders: 30% rejections – mycotoxins.

17. Models which have been used to predict mycotoxins in
relation to climatic conditions
 Predictive models: for Fusarium variety uses regional
weather parameters during ripening (DONCAST).
 Geostatistics approaches: to identify spatial hotspots which
are high risk areas for mycotoxins (Europe; USA).
 Agricultural production system simulators: in Australia
Developed an Aflatoxin Risk Index (ARI) for peanuts/maize.
 Maize: Related seasonal temp and soil moisture during
critical silking period to determine the ARI. Hot/dry
conditions. Peanuts: Fractional amounts of available soil
water during pod filling determined the ARI. Real time model
developed (Chauhan et al., 2008, 2010)

18. Worldwide prediction (an example)
Risk map – A. flavus in maize

19. Relative risk maps for ochratoxin A in grapes

20.  Predictive models which exist at present: are they
good enough to predict impact of climate change?
 Impact of drought stress and CO2 changes on crop
physiology and interaction with mycotoxin
producing fungi – required urgently
Metabolomics: changes in mycotoxins produced by
specific species??? Ratios ?? Switch between
mycotoxins?
Future trends

21.  New mycotoxins by existing drought tolerant fungal
species pre- and post-harvest ??
 Relationship between climate change factors, especially
temp x CO2 increases may stimulate pest reproduction
in staple crops.
 Food security in both developing and developed
countries could be profoundly dangerous under such
scenarios.
Future trends

22. References
 Paterson, R.R.M. and Lima, N., 2010. How will climate change
affect mycotoxins in food?. Food Research International, 43(7),
pp.1902-1914.
 Paterson, R.R.M. and Lima, N., 2017. Thermophilic Fungi to
Dominate Aflatoxigenic/Mycotoxigenic Fungi on Food under
Global Warming. International Journal of Environmental Research
and Public Health, 14(2), p.199.
 Paris, M.P.K.; Liu, Y.J.; Nahrer, K.; Binder, E.M. Climate change
impacts on mycotoxin production. In Climate Change and
Mycotoxins; Botana, M.J., Sainz, L.M., Eds.;Walter de Gruyter
GmbH: Berlin, Germany, 2015.

23. Its just the beginning of discovering the world, I mean Climate
changes and mycotoxin… Thanks for your attentions
Any questions ?