Fungal flora and mycotoxin contamination in tea: Current status, detection methods and dietary risk assessment - A comprehensive review

Tea is welcomed by consumers worldwide for its unique flavor and multiple health-promoting components. However, there is still being challenge of tea regarding microbial contaminations during cultivating, processing, storage and transportation, and the risks of potential intake of mycotoxins from tea drinking. Based on available publications, this review summarized the results, discussed the conclusions and provided prospects on the topic of fungal and mycotoxin contaminations in the commonly recognized six tea categories, i.e. green tea, white tea, yellow tea, oolong tea, black tea and dark tea. For the results of contaminations and risks differ significantly in different studies, the advantages and disadvantages of such detection techniques and risk assessment method were thoroughly compared and discussed. The fungal floras vary greatly among the different teas, and are the most abundance and complex in dark teas. Certain fungal species being reported as toxigenic fungi were isolated from teas but their capability to produce mycotoxins on teas needs to be confirmed. The mycotoxins detected from teas include aflatoxins, ochratoxin A, fumonisins, deoxynivalenol, zearalenone and enniatins, but their occurrence and prevalence differ significantly in various tea categories and in different studies, especially being determined by different analytical methods. Dietary risks of mycotoxins from teas were low, but the sample sizes of teas and consumption data are very limited, and the cumulative risks should be assessed further using more appropriate methods based on large numbers of tea contamination data and dietary surveys.