Co-occurrence of toxigenic moulds, AFs, OTA, Fusarium and Alternaria mycotoxins in fresh sweet peppers (Capsicum annuum) and their processed products

Forty-five samples of a landrace of sweet pepper (Capsicum annuum) widely cultivated in Basilicata (Italy) were screened for 17 mycotoxins and potential toxigenic fungal species. Two different LC-MS/MS methods were used for the determination of aflatoxins, ochratoxin A (OTA), Fusarium mycotoxins zearalenone (ZEA), fumonisins (FB1 and FB2), nivalenol (NIV), deoxynivalenol (DON), T-2 and HT-2 toxins and Alternaria mycotoxins altenuene (ALT), alternariol (AOH), alternariol monomethyl ether (AME), tentoxin (TTX) and tenuazonic acid (TeA). Frequency of potential toxigenic fungal species occurrence was: 87% Aspergillus Sect. Nigri; 58% Aspergillus Sect. Flavi; 38% Aspergillus Sect. Circumdati; 42% Alternaria spp.; 33% Penicillium spp. and 20% Fusarium spp. Frequency of mycotoxin occurrence and mean of positives were: 51% OTA, 29.5 µg/kg, 5 samples above the EU limit of 20 µg/kg; 31% aflatoxins, 12.8 µg/kg, two samples above the EU limit of 5 µg/kg for aflatoxin B1; 91% ZEA, 1.4 µg/kg; 78% FB2, 7.6 µg/kg; 58% FB1, 22.8 µg/kg; 38% NIV, 39.5 µg/kg; 36% DON, 6.9 µg/kg; 20% T-2 toxin, 5.6 µg/kg and 22% HT-2 toxin, 13.8 µg/kg. For the Alternaria mycotoxins, 100% of samples contained TeA, 4817.9 µg/kg; 93% TTX, 29.7 µg/kg; 56% AOH, 114.4 µg/kg; 33% AME, 13.0 µg/kg and 9% ALT, 61.7 µg/kg. Co-occurrence of mycotoxins in each sample ranged from 2 to 16 mycotoxins (mean 7). No statistical correlation was found between moulds and their mycotoxins occurrence. Within the four groups of peppers collected herein (fresh, dried, grounded and fried) higher percentages of contamination and mycotoxin levels were measured in grounded peppers, whereas much lower values were observed for fried peppers. The high percentages of positive samples and the high levels of some mycotoxins observed in this study confirm the susceptibility of peppers to mycotoxin contamination and claims for an improvement of the conditions used during production and drying process.