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Keywords:

16s rrna gene, air contamination, culturable bacteria, clone library, osmophilic, cultivation-independent methods, hop-beta-acids, debaryomyces-hansenii, pichia-anomala, maple sap, identification, storage, degradation, microorganisms, collection, Science & Technology, Life Sciences & Biomedicine, Biotechnology & Applied Microbiology, Food Science & Technology, Microbiology, 16S rRNA gene, CULTIVATION-INDEPENDENT METHODS, HOP-BETA-ACIDS, DEBARYOMYCES-HANSENII, PICHIA-ANOMALA, MAPLE SAP, IDENTIFICATION, STORAGE, DEGRADATION, MICROORGANISMS, COLLECTION, Air Microbiology, Bacteria, Beta vulgaris, Colony Count, Microbial, DNA, Bacterial, Food Contamination, Food Handling, Food Microbiology, Food Preservation, Gene Library, Industrial Microbiology, Osmolar Concentration, RNA, Ribosomal, 16S, Species Specificity, Sucrose, Temperature, Time Factors, 0605 Microbiology, 0908 Food Sciences, 1003 Industrial Biotechnology, 3006 Food sciences, 3106 Industrial biotechnology, 3107 Microbiology

Abstract:

The diversity of the bacterial population in sugar thick juice, an intermediate product in the production of beet sugar, which exhibits an extremes osmophilic environment with a water activity value (a(w)) less than 0.86, was assessed with both culture-dependent and -independent 16S ribosomal RNA (rRNA) gene-based analyses. In comparison with previous studies, the number of different thick juice bacterial species increased from 29 to 72. Remarkably, a limited, gram-positive, culturable flora, encompassing species of Bacillus, Staphylococcus and mainly Tetragenococcus dominated thick juice during storage, while a more heterogeneous and unculturable fraction of Acinetobacter, Sporolactobacillus and Thermus species could be detected in freshly produced thick juice. Notably, almost all bacteria detected in the thick juice were also detected in the air, emphasising the importance of further investigation and assessment of strategies to reduce (air) contamination during processing and storage. The discovery of the contamination source may be used for the development of management strategies for thick juice degradation resulting from microbial activity. (c) 2008 Elsevier Ltd. All rights reserved.