Quantitative PCR (qPCR) Reveals that the Aflatoxin-Free Pistachio Samples Can Be Potentially Contaminated with Fungal Materials.

Aflatoxins (AF) are the most potent group of mycotoxins that are produced by certain ascomycete fungi. These toxins can contaminate a large board of food commodities, thus causing a severe toxicity in animals and humans. The detection of fungal contamination of food is still challenging. This work determines whether an accurate relationship between the contamination of nut samples with AF and their contamination with fungal genomic DNA could be established. For this purpose, twenty samples of pistachio were collected from different local markets. The samples were subjected to two parallel protocols, namely, (i) extraction and analysis of AF and (ii) extraction and detection of fungal gDNA using a quantitative PCR (qPCR). First, our results state that five samples (25% of total samples) have shown high levels of contamination with AF which ranged between 1102 ± 0.1 and 15.84 ± 0.06 µg/kg, and this is significantly above the European legal limit. While the contamination of the rest of the samples was under the European legal limit (10 µg/kg), expectedly, our results indicate that the pistachio samples that were highly contaminated with AF were also positive for the presence of fungal gDNA, confirming, therefore, the contamination of these samples by two complementary approaches. Interestingly, six AF-free pistachio samples were positive for the fungal contamination. This study sheds light on a critical point about the potential contamination of food samples with AF-producing fungal material, addressing therefore an important message to the decision makers that the food safety should be determined by two complementary approaches, chemical and biological. [ABSTRACT FROM AUTHOR]