Commercial tea samples: a natural health ally or an Aspergillus infusion?


B Gomes1*, M Dias1,2, R Cervantes1, L Aranha Caetano1,3, C Viegas1,2

Author address:

1Environment and Health, H&TRC – Health & Technology Research Center, Lisbon, Portugal

2Environmental and Occupational Health, CHRC – Comprehensive Health Research Center, Lisbon, Portugal

3Pharmaceutical Technology, iMed.uLisboa- Research Institute for Medicines, Lisbon, Portugal

Full conference title:

10th Advances Against Aspergillosis and Mucormycosis

Date: 2 February 2022



The study aimed to characterize fungal contamination on bulk and bags teas including azole resistance profile.



Twenty different teas were selected, ten of each type, from seven different origins (China, Portugal (Azores), England, Japan, Indonesia, Ceylon (Sri Lanka) and Nepal). Fungal contamination was characterized by culture-dependent methods and detection of Aspergillus sections with toxigenic potential will be performed. Samples were inoculated onto malt extract agar (MEA) supplemented with chloramphenicol (0.05%) and dichloran-glycerol agar (DG18), including supplemented media for azole resistance screening (ITZ, VOZ, POZ), according with the proposed values of EUCAST norm.



From all the tea samples, the highest counts of fungi were obtained in leaf samples from green tea (87.7% MEA; 69.6% DG18), followed by black tea on MEA (7.9%) and DG18 (16.8%). Fungal identification evidence Aspergillus sp.was the most common genera (MEA: 67.8%; 91.9% DG18). The genera was also found in infusion samples in green tea (15.4% MEA). The highest diversity from Aspergillus sections was obtain in leaf samples from green and black tea on DG18, as follow: Nigri (65,5%), Aspergilli (17.2%), Circumdati (9.2%) and Aspergilli (33.3%) on green tea and Flavi (23.8%) and Circumdati (14.3%) on black tea. Also, 2 sections were identified in infusion samples from green tea on MEA(7.69% Nidulantes; 7.69% Fumigati). Aspergillus sp. growth in azole supplemented media (7.41% ITZ; 7.14% VOZ) along with Mucorales(11.11% ITZ; 42.86% VOZ; 36.96% POZ) evidences the trend of azole resistance associated to the genera.



Overall, the widespread of Aspergillus sp. in tea samples emphasizes the need of further investigation regarding tea consumption and human exposure. Since there is no guidance related to fungal contamination concerning this food commodity.

Abstract Number: 57

Conference Year: 2022

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