Isolation, Diagnosis and Characterization of Aspergillus sp from Tea Bags Samples and Its Ability to Produce Ochratoxin A

Abstract

This study was carry out to investigate from the contamination of packed tea samples collected from different markets with Aspergillus species. The extent of contamination of these samples with Ochratoxin A (OTA) was examined by using ELISA and the ability of Aspergillus niger to produce this toxin was determined by using the (HPLC) technique. The results showed that Aspergillus species contaminated 66 packed tea samples. Aspergillus niger was isolated from 34 black tea samples while Aspergillus ochraceus isolated from 20 samples and Aspergillus fumigatus from 23 samples. On the other hand, the green tea showed 22 samples contaminated with A.niger, 21 A. ochraceus and 15 A. fumigatus. The rate of fungi isolation from the different tea samples were Aspergillus niger (41.48 %), A. ochraceus )30.37%( and Aspergillus fumigatus (28.1%).The quantitative detection of Ochratoxin A by using ELISA technique showed the presence of OTA in tea samples as it reached in the samples of Ahmad black tea (2.27 μg/kg), which is the least concentrated than the rest of the studied teas and the highest concentration rate (6.46 μg /kg) it appeared in samples of Ahmed green tea. The results of quantitative estimation using (HPLC) also showed the ability of A. niger to produce OTA as it produced this toxin at a concentration of 12.36 ppb / 100 ml.