Soares, Célia

Venâncio, Armando

Universidade do Minho: RepositoriUM

Semana de Engenharia 2010 Guimarães, 11 a 15 de Outubro   THE ISOLATION OF ASPERGILLUS SPP FROM HARVESTED MAIZE IN THREE PORTUGUESE REGIONS Célia Soares and Armando Venâncio IBB - Institute for Biotechnology and Bioengineering Centre of Biological Engineering , University of Minho, Campus Gualtar, 4710-057; Braga, Portugal                  KEYWORDS Maize, Aspergillus species, Mycotoxins.  INTRODUCTION In Portugal, maize constitutes one of the most important crop and it is the cereal that involves more agriculture explorations from the North to the South of the country.  Maize is colonized and contaminated by different species of fungus including Aspergillus, Fusarium, and Penicillium (Gioni et al. 2007). Aspergillus spp., among other species, are usually associated with this cereal, during its drying and storage. The most important Aspergillus spp. are Aspergillus flavus and Aspergillus parasiticus, due to the fact that, together with Aspergillus nomius, are the main producers of aflatoxins, a mycotoxin proven to have toxic effects in mammals (Sapamundo et al. 2007). It is also known that A. flavus species can produce  cyclopiazonic acid, a mycotoxin that occurs naturally in maize and peanuts as a co-contaminant with aflatoxins (Vaamonde et al. 2003).  To prevent the fungi’s development and the subsequent  production of mycotoxins it is important to monitor the production chain and to create a predictive model, based in two of the most important abiotic factors, water activity and temperature. The aim of this project is to study the level of contamination of maize with aflatoxigenic fungi right after harvesting and during storage time, in three Portuguese regions, allowing with this approach, the prevention of occurrence of mycotoxins in the final product.  MATHERIALS AND METHODS The survey was carried out in three Portuguese regions, with producers belonging  to the National Producers Association of Maize and Sorghum (ANPROMIS – Associação Nacional de Produtores de Milho e de Sorgo): - A - Cooperativa Agrícola de Coimbra (Coimbra, Coimbra disctrict)   - B - AGROMAIS (Riachos/Torres Novas, Santarém district)  - C - CERSUL (Santa Eulália/Elvas, Portalegre district) The samples were collected between November 2008 and April 2009.  RESULTS AND DISCUSSION -  The sampling occurred in three distinct  places of the storage chain - Maize samples were plated in MEA10 (malt extract medium agar with 10% of NaCl) and the resulting fungi were isolated to MEA; -  Presence of mycotoxins was tested by high profile liquid chromatography (HPLC), by growing the Aspergillus spp. isolates in YES (for aflatoxins) and CYA (for OTA and CPA) -  It was possible to obtain, from a total of 132 samples, 1075 isolates from the gender Aspergillus and 732 of this isolates were tested for mycotoxins;  - The isolates were divided in three distinct groups: Aspergillus section Flavi (tested for CPA and aflatoxins), Aspergillus section Nigri (tested for OTA) and Other Aspergillus (tested for CPA and OTA).   Results show that there are differences between the incidence of the three groups of Aspergillus in the regions. Whereas in Elvas (Portalegre) and Riachos (Santarém) there is a high incidence of Aspergillus section Nigri, the same doesn't happens in Coimbra. This may be explained by the fact that black aspergilli are more resistant to the higher solar exposure and higher temperatures, typical of these regions. Aspergillus section Flavi, are more common in the samples after leaving the dryers. Most of them are producers, the great majority of CPA and less than 50% of aflatoxins. A very small percentage of Aspergillus section Nigri are OTA producers even though they are abundant in the samples of two regions; Aspergiilus section Flavi are very common in all regions even though they are more common after drying and storage. The great majority of fungi are not producers, but there is an alarming quantity of producers of aflatoxins and CPA.  CONCLUSION It is possible to correlate the climate with the kind of isolates obtained, being  Aspergillus section Nigri associated with the regions of hotter and dryer climates.   REFERENCES Richard, E., Heutte, N., Bouchart, V., Garon, D., Evaluation of fungal contamination and mycotoxin production in maize silage, Animal Feed Science and Technology 148 (2009) 309–320; Sapamundo, S., Devlieghere,F., Geeraerd, A., Meulenaer, B., Impe, J. F., Debevere, J., Modelling of the individual and combined effects of water activity and temperature on the radial growth of Aspergillus flavus and A. parasiticus on corn, Food Microbiology 24 (2007) 517-529 ACKNOWLEDGEMENTS  Célia Soares was supported by a grant from Fundação para a Ciência e Tecnologia (reference SFRH / BD / 37264 / 2007)  Luís Abrunhosa was supported by a grant from Fundação para a Ciência e Tecnologia (reference SFRH/BPD/ 43922/2008) The authors are grateful for the support and cooperation of ANPROMIS   

The isolation of Aspergillus spp from harvested maize in three Portuguese regions

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Universidade do Minho: RepositoriUM

Universidade do Minho: RepositoriUM