Food Microbiology

Tea drinks are popular so their consumption is growing all over the world and becoming part of many lifestyles. During harvesting, handling, storage and distribution, teas are subjected to contamination by various molds, which may be responsible for spoilage and production of mycotoxins. According to mentioned the goal of this study was to evaluate presence of toxigenic molds and their secondary metabolites − ochratoxin A (OTA) in black and herbal teas on the Serbian market. Analyzed samples were collected from various retail shops from January 2015 until December 2016. Total number of analyzed samples was 787 (336 samples of black teas and 451 samples of herbal teas) and they were tested on molds according to ISO methodology (ISO 21527-2) and identified by dichotomous keys. The most predominant molds detected were: Aspergillus, Mucor, Rhizopus and Cladosporium. Ochratoxin A (OTA) is produced by Aspergillus spp. (A. ochraceus, A. westerdijkiae, A. steynii, A. carbonarius, A. foetidus, A. lacticoffeatus, A. niger, A. sclerotioniger, A. tubingensis) so further analysis on OTA were conducted on samples in which were detected Aspergillus spp. by validated method (based on BS EN 14132). Aspergillus niger and Aspergillus flavus have been associated with black tea (56 samples). Aspergillus section Nigri, including Aspergillus niger, A. acidus, A. tubingensis and A. carbonarius were found in herbal teas (91 samples) available on the Serbian market. Production of OTA was quantified in mold isolate from black tea in 5% of samples (1, 2-4, 6 μg/kg). As far as isolates from herbal teas are concerned it was confirmed that 16% of A. niger isolates were able to produce OTA in quantity of 0.89-6.1 μg/kg. In order to minimize the health risks resulting from the consumption of teas contaminated by toxigenic mold and mycotoxins, it is imperative to monitor the presence of these contaminants prior their use.