Effects of different media on the enrichment of low numbers of Shiga toxin-producing Escherichia coli in mung bean sprouts and on the development of the sprout microbiome
| Autor: | Taurai Tasara, H. Margot, Han Joosten, Roger Stephan, Marcel H. Zwietering |
|---|---|
| Přispěvatelé: | University of Zurich, Stephan, Roger |
| Rok vydání: | 2016 |
| Předmět: |
0301 basic medicine
Salmonella Firmicutes 030106 microbiology Selective compound 610 Medicine & health medicine.disease_cause Microbiology Levensmiddelenmicrobiologie 03 medical and health sciences Proteobacteria Microbiome analysis medicine Microbiome Escherichia coli Pathogen 10082 Institute of Food Safety and Hygiene 1106 Food Science Novobiocin VLAG Shiga-Toxigenic Escherichia coli biology Microbiota Vigna 2404 Microbiology Background flora General Medicine Incubation temperature biology.organism_classification Enterobacteriaceae Bacterial Load Culture Media STEC 030104 developmental biology Seedlings Food Microbiology 570 Life sciences bacteria Food Science medicine.drug |
| Zdroj: | International Journal of Food Microbiology, 232, 26-34 International Journal of Food Microbiology 232 (2016) |
| ISSN: | 0168-1605 |
| Popis: | Sprouted seeds have been implicated in a number of serious outbreaks caused by Salmonella and Shiga toxinproducing Escherichia coli. Sprouts pose a very complex challenge to bacterial pathogen enrichment and detection since they naturally contain high levels of background microflora including members of theEnterobacteriaceae. As such, the currently used method cannot ensure reliable detection of STEC in sprouts. In this study, we compared different media for the enrichment of Enterobacteriaceae in their ability to promote the growth of stressed STEC at 37 °C and 42 °C. Mung bean sprouts were spiked with low levels of STEC and their growth was recorded over time. In addition, the microbiome of mung bean sprouts was analysed before and after enrichment. Our results indicate that the growth of dry-stressed STEC is comparable in all of the testedenrichment media except for mTSB + Novobiocin and not influenced by the incubation temperature. Low levels of STEC spiked into the sprouts resuspended in media only grew to levels of around 4 log cfu/ml during enrichment,which could reduce the probability of detection. Proteobacteria was the dominant phylum detected within the microbiome of non-enriched mung bean sprouts. During enrichment in EE-broth, Proteobacteria remained the most abundant phylum. In contrast, during enrichment in BPW the relative abundance of Proteobacteria decreased whereas Firmicutes increased when compared to the non-enriched mung bean sprout microbiome. The microbiome composition was not significantly influenced by the incubation temperature during enrichmentin both BPW and EE-broth. This is the first study to examine the microbiome on sprouted mung bean seeds during BPW and EE enrichment and relates the bacterial community composition changes to the enrichment of pathogens. |
| Databáze: | OpenAIRE |
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