Aspergillus and Penicillium toxins in chestnuts and derived products produced in Italy

Occurrence of aflatoxins, ochratoxin A, sterigmatocystin, cyclopiazonic acid, citrinin, roquefortine C and mycophenolic acid in fresh chestnuts and dried chestnut products was surveyed. A total of eighty-two samples were collected from retail outlets located in northern Italy. After specific extraction and purification through immunoaffinity or prepacked columns, mycotoxins were analysed using HPLC-FLD or HPLC-MS/MS. In fresh chestnuts, mycotoxins were rarely detected, while a widespread contamination was found in dried products, particularly in chestnut flour. The incidence of aflatoxin B1 was 92.0 and 40.0% in chestnut flour (maximum value 58.6 µg kg-1) and dried chestnuts, respectively; in chestnut flour, the percentage of samples exceeding the value of 2.0 µg kg-1 for aflatoxin B1 (maximum limit fixed by EC Regulation 165/2010 in dried fruits) was 24.0%. Chestnut flour was also often contaminated with ochratoxin A, citrinin, roquefortine C and mycophenolic acid, showing sometimes high values (particularly for mycophenolic acid); in 80% of samples, more than four mycotoxins were detected. To the best of our knowledge, no data are available from previous studies about the occurrence of citrinin, roquefortine C and mycophenolic acid in chestnuts and derived products. These results showed that probably the contamination occurred in the post-harvest, during exsiccation, storage and sorting; the high incidence and concentration found in chestnut flour are probably related to the practice of producing it by grinding of the product coming from sieving of dried chestnuts.