Spatio-temporal analysis of post-harvest moulds genera distribution on stored durum wheat cultivated in Tunisia Nesrine Belkacem-Hanfi a, b , Nabil Semmar c , Isabelle Perraud-Gaime b , Amel Guesmi a , Marwa Cherni a , Imen Cherif a , Abdellatif Boudabous a , Sevastianos Roussos b, * a Laboratoire Microorganismes et Biomolécules Actives, Faculté des Sciences de Tunis, Université de Tunis El Manar, 2092 Tunis, Tunisia b Equipe Ecotechnologies et Bioremédiation, IMBE-UMR CNRS-7263/IRD-237, Case 421, Aix Marseille Université, Campus Etoile, Faculté St Jérôme, 13397 Marseille cedex 20, France c ISSBAT, Université de Tunis El Manar, 2092 Tunis, Tunisia article info Article history: Accepted 17 August 2013 Keywords: Stored-wheat Post-harvest moulds Biodiversity Correspondence analysis Cluster analysis Mycological patterns Silos Tunisia abstract Wheat represents a principal ingredient in traditional Tunisian diet including couscous, bread, pasta and biscuits. Northen Tunisia is an important growing area of wheat which after harvest is stored in silos and on farm. The cereal grains can become contaminated by post-harvest moulds during storage in silos under unfavorable conditions leading to a decrease in quality, packing and marketing of wheat. In this study, a mycological survey was undertaken to determine the biodiversity of post-harvest moulds on durum wheat stored in silos localized in five regions of Northern Tunisia and to investigate changes during the storage period. A total of 127 samples were obtained from Oued Mliz, Jendouba, Ksar Mezouar, Mateur and Ghezala silos during 2010e2011 and 2011e2012 wheat seasons. After sampling, seeds were placed on Potato Dextrose Agar medium (PDA) for 7 days of incubation at 28  C. A total of 6035 strains of filamentous fungi were isolated. The quantitative and qualitative changes on wheat mycoflora during storage were statistically explored by multivariate methods including correspondence and hierarchical cluster analysis. The most pre- dominant post-harvest moulds genera isolated were Alternaria (28%), Fusarium (19%), Penicillium (19%), Aspergillus (14%), Mucor (8%) and Rhizopus (7%). Various genera of fungi imperfecti, including Ulocladium, Geotrichum, Chaetomium, Trichothecium, Paecilomyces, Aureobasidium and Chrysonilia (anamorphic Neurospora), and the Mucorales genera Lichtheiia and Syncephalastrum accounted for the remainder of about 6% of the total. Statistical data analysis revealed six mycological patterns corresponding to six distinct communities as characterized by the prevalence of different moulds. Such patterns clearly showed different spatio-temporal variability indicating that distribution and evolution of moulds during storage was sensitive to geographic location, year of sampling and short or long-term storage. Ó 2013 Elsevier Ltd. All rights reserved. 1. Introduction In Tunisia, wheat is one of the most important crops being cultivated on 1.6 million hectares of the total agricultural land (5 million hectares). In 2012, wheat production reached 1.1 million metric tons including 900,000 metric tons of durum wheat and 200,000 metric tons of bread wheat. Northern Tunisia represents the main wheat production area where harvested wheat is stored in silos and in farms. Good agricultural practices during cultivation and harvesting must be used for protection against fungal attacks that could become a source of post-harvest fungi during storage. At harvesting and during the different phases of wheat processing from harvest to marketed products (including transport, storage and processing conditions for grain and grain products), seeds are often contaminated by both fungi and their metabolites (Riba et al., 2008). Under unfavorable conditions, stored wheat grains can be sub- jected to post-harvest mould deterioration caused by Alternaria, Aspergillus, Fusarium, Mucor , Rhizopus, and other genera especially if drying and storage phases are poorly managed (Magan et al., 2003). Fungal contamination of wheat may affect kernel quality like germination capacity, discoloration, and modification of nutritional matrices leading to mycotoxin production. Factors like water availability, temperature, humidity and atmospheric * Corresponding author. Tel.: þ33 4912 89103. E-mail address: sevastianos.roussos@imbe.fr (S. Roussos). Contents lists available at ScienceDirect Journal of Stored Products Research journal homepage: www.elsevier.com/locate/jspr 0022-474X/$ e see front matter Ó 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.jspr.2013.08.008 Journal of Stored Products Research 55 (2013) 116e123