Taylor & Francis, Food Additives and Contaminants: Part A: Chemistry, Analysis, Control, Exposure and Risk Assessment, 1(31), p. 149-155
DOI: 10.1080/19440049.2013.862349
Full text: Unavailable
Fumonisins (FBs), carcinogenic mycotoxins, are known to be typically produced by several phytopathogenic fungal species belonging to the genus Fusarium. F. proliferatum and F. verticillioides, two important pathogens of maize worldwide, are the most common species that produce fumonisins (FBs). The main FBs produced by these species are FB1, FB2 and FB3. Moreover, recently, fungal strains belonging to Aspergillus niger have been also reported to produce fumonisins (in particular, FB2 and FB4). In a survey on maize carried out in Central Italy, 17 maize kernel samples were collected at harvest and analyzed for FB1, FB2 and FB3, as well as fungal contamination, with a particular attention to the species producing FBs. All 17 samples were contaminated by F. verticillioides and/or F. proliferatum at a level ranging from 13% to 100% of kernels. However, 10 out of 17 samples were contaminated also by Aspergillus section Nigri with a range from 6% to 68% of kernels. There was a significant inverse logarithmic relationship between levels of Fusarium and Aspergillus contamination. All samples were contaminated by FBs; FB1 ranged from 0.09 to 30.2 μg/g, whereas FB2 ranged from 0.04 to 13.2 μg/g. The ratio of FB2/FB1 contamination in the maize samples was evaluated and the highest values occurred in samples contaminated with Aspergillus section Nigri. Thirty strains of Aspergillus section Nigri isolated from these samples were molecularly identified (based on sequences of 2 housekeeping genes) and analysed for their capability to produce FB2. Among the 30 strains isolated, 12 were identified as Aspergillus welwitschiae (syn A. awamori) and 18 as A. tubingensis. FB2 was produced by 5 out of 12 strains of A. welwitschiae within a range of 0.20-5 μg/g. This is the first report showing the capability of Aspergillus section Nigri from maize to produce FB2 and their possibility to contribute to FB accumulation in kernels.