Mycotoxin production in liquid culture and on plants infected with Alternaria spp. isolated from rocket and cabbage.

Fungi belonging to the genus Alternaria are common pathogens of fruit and vegetables with some species able to produce secondary metabolites dangerous to human health. Twenty-eight Alternaria isolates from rocket and cabbage were investigated for their mycotoxin production. Five different Alternaria toxins were extracted from synthetic liquid media and from plant material (cabbage, cultivated rocket, cauliflower). A modified Czapek-Dox medium was used for the in vitro assay. Under these conditions, more than 80% of the isolates showed the ability to produce at least one mycotoxin, generally with higher levels for tenuazonic acid. However, the same isolates analyzed in vivo seemed to lose their ability to produce tenuazonic acid. For the other mycotoxins; alternariol, alternariol monomethyl ether, altenuene and tentoxin a good correlation between in vitro and in vivo production was observed. In vitro assay is a useful tool to predict the possible mycotoxin contamination under field and greenhouse conditions

Static hot air and infrared rays roasting are efficient methods for aflatoxin decontamination on hazelnuts

Aflatoxins are a group of secondary metabolites produced by members of Aspergillus Section Flavi that are dangerous to humans and animals. Nuts can be potentially contaminated with aflatoxins, often over the legal threshold. Food processes, including roasting, may have different effects on mycotoxins, and high temperatures have proven to be very effective in the reduction of mycotoxins. In this work, two different roasting methods—traditional static hot air roasting and infra-red rays roasting—were applied and compared for the detoxification of hazelnuts from Italy and Turkey. At the temperature of 140 °C for 40 min of exposure, detoxification was effective for both roasting techniques. Residual aflatoxins after infra-red rays treatments were lower compared to static hot air roasting. On Italian hazelnuts, residual aflatoxins were lower than 5%, while for Turkish hazelnuts they were lower than 15% after 40 min of exposure to an infra-red rays roaster. After roasting, the perisperm was detached from the nuts and analyzed for aflatoxin contents. Residual aflatoxins in the perisperm ranged from 80% up to 100%. After roasting, the lipid profile and the nutritional quality of hazelnuts were not affected. Fatty acid methyl esters analyses showed a similar composition for Italian and Turkish hazelnuts

Fusarium oxysporum f. sp. echeveriae, a novel forma specialis causing crown and stem rot of Echeveria agavoides

analysis based on the ITS region confirmed the pathogen as Fusarium oxysporum. In order to identify the forma specialis, thirteen isolates obtained from infected tissues were used for phylogenetic analysis based on four polygalacturonase genes (Pg1, Pg5, Pgx1 and Pgx4) together with the translation elongation factor 1-alpha (EF-1alpha) gene. Sequences generated in this study were aligned with other formae speciales of Fusarium oxysporum from GenBank to construct phylogenetic trees. Eleven isolates of a new forma specialis, Fusarium oxysporum f. sp. crassulae described on Crassula ovata, were added to the analysis based on Pg5 and Pgx1 genes. The results obtained for each genomic region showed that the isolates derived from E. agavoides are in a unique group well separated from other formae speciales already described. The first report of F. oxysporum on E. agavoides together with the results obtained in this study suggest a new forma specialis, here named F. oxysporum f. sp. echeveriae