Mycological evaluation of a sorghum grain of Argentina, with emphasis on the characterization of Fusarium species A. Saubois 1 * , E. Piontelli Laforet 2 , M. C. Nepote 1 and M. L. Wagner 3 Characterization of the internal mycota of sorghum grain from the Santa Fe Province of Argentina was performed, particularly for those species considered potentially toxigenic. The prevalence of these spe- cies in the grains was recorded. The distribution of Fusarium species and the percentage of colonized kernels was also recorded. Observations were made using a light ¢eld microscope and a stereomicro- scope. Isolation was carried out by direct plating on potato-dextrose agarchloramphenicol. For iden- ti¢cation and con¢rmation, speci¢c media and culturing regimes were followed according to the literature. Total fungal counts by dilution plate on dichloran-rose Bengal-chloramphenicol agar, and moisture content measures were also performed. Total fungal counts were in the range of 2?4610 4 ^2?5610 5 cfu g 71 . Investigation of the internal mycota revealed a prevalence of species of Fusarium, Alternaria and Curvularia, which were present ¢rst in the total of samples. The most impor- tant potentially toxigenic species belonged to Fusarium, Alternaria and Penicillium, but potentially toxigenic species of Aspergillus and Phoma were also present. Species of Fusarium were F. monili- forme Sheldon, F. chlamydosporum Wollenw. & Reinking, F. semitectum Berk. & Ravenel and F. sub- glutinans (Woll. & Rein.) Nel., Touss. & Mar., in order of frequency of occurrence. The highest percentages of colonized kernels corresponded to the ¢rst two species. A close association was ob- served between F. moniliforme and A. alternata in 90% of the samples. # 1999 Academic Press Introduction Grains constitute a major source of food, feed and the raw material for many industrial pro- ducts. From the early stages of their formation on growing plants until their use and con- sumption, they are subject to damage of several biological agents, mainly fungi (Christensen 1991). Before harvest, fungi may cause dis- colouration, blight and other injuries, and a¡ect the quality of the seeds for planting, for food and animal feed, and for processing (Chelkowski 1991, Christenen 1991, Frisvad and Samson 1991, Lacey et al. 1991). Fungi that invade grains in storage may be responsible for reduction in germinability, discolouration, and total spoilage (including heating and losses of dry matter) (Lacey et al. 1991, Lacey and Magan 1991). Both in the ¢eld and in storage, ORIGINAL ARTICLE *Corresponding author. 1 Ca¨ tedrade Microbiolog|¨ a, Departamento de Biotecnolog|¨ a, Facultad de Ingenier|¨a Qu|¨ mica, Universidad Nacional del Litoral, Santiago del Estero 2829, 3000 Santa Fe, Argentina 2 Ca¨ tedrade Micolog|¨a, Facultad de Medicina, Universidad de Valpara|¨so, Casilla 92-V, Valpara|¨ so, Chile 3 Ca¨ tedrade Farmacobota¨ nica y Museo de Farmacobota¨ nica Facultad de Farmacia y Bioqu|¨ mica, Universidad do Buenos Aires, Junin 956,1113 Buenos Aires, Argentina Received: 15 June 1998 0740-0020/99/050435+11 $30.00/0 # 1999 Academic Press Food Microbiology, 1999, 16, 435^445 Article No. fmic.1998.0250 Available online at http://www.idealibrary.com on