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Advisor(s)
Abstract(s)
Introduction. Tea and infusions are common beverages worldwide, prepared by infusing Camellia sinensis or other medicinal plants (eg. Melissa officinalis) with boiling water. Contamination by specific strains of filamentous fungi, such as Aspergillus sp., may originate health risks. While azole antifungal drugs are first-line therapy against fungal infections, the exposure of medicinal plants to azole fungicides in conventional agriculture can promote azole resistance, leading to therapeutic failure. Considering the growing risks to public health, the fungal contamination of tea and medicinal samples commercially available in Portugal was evaluated. Methodology. Samples (N=40) of different origins of conventional and biological agriculture were collected at supermarkets and herbalist shops in January 2021. Infusions were prepared according to ISO 3103:2019. Samples were also extracted as previously described and inoculated in fungal selective culture media (MEA and DG18) and in Sabouraud dextrose agar (SDA) medium supplemented with 4 mg/L itraconazole (ITR), 2 mg/L voriconazole (VOR), and 0.5 mg/L posaconazole (POS). Plates were incubated at optimal conditions for fungal growth. Fungal counts were determined as colony forming units (CFU) per gram and fungal morphology was analyzed by microscopy. Results. The average mycobiota was 359.1 ± 816.2 (MEA) and 559.1 ± 1263.8 (DG18) CFU/g in extracted samples, and 341.7 ± 277.2 (MEA) and 183.3 ± 271.6 (DG18) CFU/g in infusions. Regarding azole resistance, the most prevalent species were Aspergillus sp. (48% ITR) and C. sitophila (39% ITR, 47% VOR, 92% POS) in extracted samples, and C. sitophila (50% ITR, 37% VOR, 57% POS) in infusion samples. Among Aspergillus sp., the most prevalent sections were Nigri (96% MEA, 74% DG18, 72% SDA) and Circumdati (100% ITR) in extracted samples, and Fumigati (46% MEA, 100% SDA) in infusion. Conclusions. Fungal contaminants were present in tea samples and medicinal plants for infusion, including azole-resistant fungi. Relevance. The presence of Aspergillus sp., particularly section Fumigati, resistant to azoles in infusions may represent a health risk for consumers, especially immunocompromised individuals. Mycotoxins detection and correlational statistical analysis are ongoing to further determine whether there is a relation between sample origin, fungal contamination, and mycotoxigenic profile.
Description
IPL/2020/TEAResMyc_ESTeSL. Project "Resistant mycobiota and mycotoxigenic profile of tea and medicinal plants”.
FCT_UIDB/05608/2020. FCT_UIDP/05608/2020.
FCT_UIDB/05608/2020. FCT_UIDP/05608/2020.
Keywords
Azole resistance Fungal contamination Tea Medicinal plants Aspergillus fumigatus Portugal FCT_UIDB/05608/2020 FCT_UIDP/05608/2020. IPL/2020/TEAResMyc_ESTeSL
Citation
Simões A, Faria M, Dias M, Viegas C, Caetano LA. Fungal contamination and azole-resistance in tea and other medicinal plants commercially available in Portugal. In: International Conference on Food Contaminants – ICFC 2021 [online], Instituto Nacional de Saúde Dr. Ricardo Jorge (Portugal), September 27-28, 2021.