TY - GEN A1 - Borzekowski, Antje T1 - Fungi Isolated from Indonesian Tempeh Production Capable of Zearalenone Conjugation N2 - Zearalenone (ZEN) and its metabolites such as the phase II sulfate and glucoside conjugates have been detected in food and feed commodities1. In addition to these naturally occurring ZEN conjugates, food fermentation by fungi may also lead to conjugate formation. Fungal strains of the genera Rhizopus and Aspergillus are used in tempeh fermentation, and it is known that some strains can conjugate ZEN2. Moreover, during this process the reductive phase I metabolites α- and β-zearalenol (α-/β-ZEL) and their conjugates are formed by the same microorganisms in vitro. As the conjugates can be hydrolysed by human intestinal microbiota, also sulfates and glucosides represent a relevant source for the human exposure to ZEN. If the unprocessed grains for tempeh fermentation like soybeans and/or maize are contaminated with ZEN, upon analysis ZEN content of the final tempeh product may be underestimated, because ZEN has been conjugated during food processing. Very recently, the EU-CONTAM Panel found it appropriate to set a group tolerable daily intake (TDI) expressed as ZEN equivalents for ZEN and its modified forms (phase I and phase II metabolites)3. In this study a total of 70 strains of fungal species commonly found in tempeh fermentation were screened for ZEN metabolite formation in vitro. The fungal strains were isolated from inocula or fresh tempeh from different tempeh producers and market areas in Indonesia. ZEN (c = 0.3 µM) was added to liquid cultures of the fungi. After two days of incubation the media were analyzed for metabolite formation by HPLC-MS/MS. The conjugate formation varied with the fungal strain. In most cultures ZEN-14-sulfate was the major metabolite accompanied by rapid disappearance of ZEN; also, formation of α- and β-ZEL, ZEN-16-glucoside and two ZEL-sulfates has been observed. The in vitro-screening showed that fungal strains used in tempeh fermentation have the potential for ZEN conversion leading to ZEN and ZEL conjugate formation. Therefore, reference substances of ZEN conjugates are urgently needed for monitoring food safety of tempeh and other fermented products manufactured from grains that can be contaminated with ZEN. T2 - 39th Mycotoxin Workshop CY - Bydgoszcz, Poland DA - 19.06.2017 KW - Mycotoxin KW - Tempeh PY - 2017 UR - https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/40964 AN - OPUS4-40964 AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany