Screening strategy targeting the presence of food enzyme-producing fungi in food enzyme preparations

Food enzymes (FE) are often produced through microbial fermentation, for which fungal strains are commonly used. Verifying the absence of viable strains and associated DNA of producer organisms in FE's is important for both the safety evaluation of the product and the control of the food chain quality. For this purpose, a first line generic screening strategy, targeting FE producing fungal species, is proposed, based on a PCR amplification of the internal transcribed spacer (ITS) region followed by sequencing and sequence analysis for genus identification. To simplify the sequence analysis, an in-house constructed database was assembled, containing ITS reference sequences from the FE producing fungal species available from public databases and our own generated amplicons. Finally, the performance of the proposed strategy was assessed in terms of specificity and sensitivity. Some experiments were also conducted in order to evaluate the applicability of the method and to verify the feasibility of its implementation in control laboratories.