Sterigmatocystin Occurrence in Paddy and Processed Rice Produced in Italy in the Years 2014–2015 and Distribution in Milled Rice Fractions

The occurrence of sterigmatocystin (STC) in paddy and processed rice samples produced in Italy was surveyed. After extraction and purification, STC was analysed using HPLC-MS/MS. STC was detected in all paddy rice samples (n = 49), in the range 0.29-15.85 μg·kg-1. As regards processed rice, a widespread contamination was found in brown and parboiled rice. All the brown rice samples were contaminated between 0.12 and 1.32 μg·kg-1; for parboiled rice, the incidence was 90.9% and the maximum level was 1.09 μg·kg-1. The contamination in white rice was significantly lower (p < 0.01). The STC distribution in different rice fractions, obtained by the de-hulling and polishing processes, was evaluated. After de-hulling, the STC percentage remaining in brown rice was in the range 21.2%-30.8%. The polishing process, from brown to white rice, caused another remarkable decrease of contamination; the STC remaining in white rice was 2.2%-8.3% of the amount found in paddy rice.