Tag Archives: Mould identification

288–297 M. Surženko, K. Kontram and I. Sarand
PCR–based fingerprinting and identification of contaminative fungi isolated from rye breads
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PCR–based fingerprinting and identification of contaminative fungi isolated from rye breads

M. Surženko¹², K. Kontram¹² and I. Sarand²*

¹Competence Center of Food and Fermentation Technologies (CCFFT), Akadeemia tee 15A, EE12618 Tallinn, Estonia
²Tallinn University of Technology, Department of Chemistry and Biotechnology, Akadeemia tee 15, EE12618 Tallinn, Estonia
*Correspondence: inga.sarand@ttu.ee

Abstract:

Fungi are the most frequent cause of microbial spoilage in baked products, including rye bread. As the baking process destroys fungal spores in bread, the post–processing is the main source for mould contamination. Rapid detection methods are needed to track down the origin of the contamination source. In the present research we used a combined molecular approach consisting of PCR–fingerprinting with an M13 primer and further identification of each genotype by amplification and sequencing of the Internal Transcribed Spacer region, the β–tubulin gene and the D1/D2 region of the large subunit of the 28S rDNA. Different rye breads from five bakeries were stored plastic–packed for one month and the fungal colonies with unique morphology were isolated from the bread surfaces. Based on random amplified polymorphic DNA analysis using M13 primer 50 fungal isolates were clustered into eight groups and identified as Aspergillus chevalieri, Aspergillus flavus/oryzae, Aspergillus niger, Aspergillus tubingensis, Penicillium citrinum, Penicillium corylophilum, Saccharomyces cerevisiae and Wickerhamomyces anomalus species. Sequencing of the β–tubulin gene and the ITS region showed an equal efficiency for the identification of Penicillium species, whereas only the sequence of the β–tubulin gene allowed us to identify most isolates from the genus Aspergillus including closely–related black–spored Aspergillus species. Yeasts were identified at the species level based on the sequences of the Internal Transcribed Spacer region and the D1/D2 region.BSE2017_326_Surženko

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