First report of Aspergillus species in green pistachio of Bronte

Abstract

Aspergillus contamination of pistachios causes significant product losses and potential presence of mycotoxins, particularly aflatoxin B1 (AFB1), and ochratoxin A (OTA). These toxins, which threaten human health, are strictly monitored by most nations. Italian pistachios produced in Bronte, Sicily, have high nutritional value and unique organoleptic properties, but the extent to which they contain these contaminants is unknown. Aspergillus spp. isolated from Bronte pistachios (cultivar Napoletana) were assessed for their ability to synthesize OTA or AFB1. Aspergillus occurrence in pistachio samples was measured at 1137 cfu g-1 for in shell pistachios and 770 cfu g-1 for kernels. The predominant isolated Aspergillus species was A. niger representing 74% of section Nigri (black isolates) and 47% of all Aspergillus isolates. Within section Flavi, A. flavus comprised 83% of green isolates. Only one black isolate (identified as A. carbonarius) had high OTA production, but all the A. flavus isolates had potential to produce AFG1 and AFB1, with AFB1 produced amount ranging from 0.1 to 8498 ng mL-1 of culture filtrate.