Post-harvest fungi production in different storage conditions of the cereals

Crops are exposed to fungal contamination both on the field before harvest, and especially during storage for longer periods of time in improper conditions. Concerning the origin of fungi contamination the following sources exist: contamination from the warehouse or silo dispersion, the predominant fungi is Aspergilius and Penicillium, contamination remaining from the field before harvest with: Clamidosporium, Fusarium, Mucor, Rizopus and advanced alteration, which associates more rare types in remanent contamination. In this paper, the influence of storage conditions on the fungi growth and mycotoxins production in cereals was studied. Cereal samples (wheat, maize, barley and oats) collected from warehouse, individual silos and storage cells from the west side of Romania were analysed. The cereals were sampled from private producers, who reported the information regarding storage conditions. The storage period ranged between 6 months and over 1 year. The main measures of conditioning applied to samples before storage were related to: drying, pest removal, aeration and cleaning. Also, the main parameters (temperature, humidity, ventilation) during the storage were monitored in order to preventthe toxins production. The method used for fungal species with mycotoxigen potential identification was microbiological assay. The experimental results indicated that the fungus species isolated and identified were Aspergillus (flavus and terreus, Fusarium roseum, Penicillium sp., Chaetomium sp. and Cladosporium sp. The most frequent Fusarium fungal species in cereal samples were identified F. culmorum, DON mycotoxin producers, F. subglutinans, fumonisin producers and F. acuminatum, non mycotoxin producer. Fusarium species was identified in 45 % maize samples, 25% wheat samples, 100% triticale and barley samples and 0% in oats samples. In order to avoid the production of mycotoxins after harvest, it is advisable to dry the grain and bring to optimum moisture retention, less than 14%. Also, post-harvest contamination can be avoided by monitoring and keeping optimal grain storage conditions.