Molecular detection of Aspergillus niger and ochratoxin A in dried fruits and vegetables

Dried fruits and vegetables are highly susceptible to colonization by Aspergillus species, particularly Aspergillus niger, which may lead to the formation of ochratoxin A, a nephrotoxic and potentially carcinogenic mycotoxin. Although ochratoxin A contamination in dried fruits has been widely documented, data regarding its occurrence in dried vegetables remain limited. This study aimed to detect A. niger in dried fruits and vegetables using classical mycological examination and real-time polymerase chain reaction, and to determine ochratoxin A levels by enzyme-linked immunosorbent assay. Microscopic analysis showed A. niger contamination in 86.5 % of vegetable samples and 81.8 % of fruit samples. Real-time polymerase chain reaction confirmed the presence of A. niger in 94.4 % of vegetable isolates and 100.0 % of fruit isolates. Ochratoxin A was detected in 18.5 % of dried vegetables, with only one sample exceeding European Union limits. In contrast, it was found in 80.0 % of fruits, of which 40.0 % exceeded regulatory limits. The exceedance rate was significantly higher in fruits than in vegetables (p < 0.05). These findings indicate that dried fruits pose a higher mycotoxic risk than dried vegetables and highlight the need for improved hygienic drying practices and routine mycotoxin monitoring.