| Title: | Amino acid conversions by coagulase-negative staphylococci in a rich medium: Assessment of inter- and intraspecies heterogeneity |
| Author(s): | Stavropoulou DA; Borremans W; De Vuyst L; De Smet S; Leroy F; |
| Address: | "Research Group of Industrial Microbiology and Food Biotechnology (IMDO), Faculty of Sciences and Bioengineering Sciences, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium. Laboratory for Animal Nutrition and Animal Product Quality, Department of Animal Production, Ghent University, Melle, Belgium. Research Group of Industrial Microbiology and Food Biotechnology (IMDO), Faculty of Sciences and Bioengineering Sciences, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium. Electronic address: fleroy@vub.ac.be" |
| DOI: | 10.1016/j.ijfoodmicro.2015.04.048 |
| ISSN/ISBN: | 1879-3460 (Electronic) 0168-1605 (Linking) |
| Abstract: | "The ability of coagulase-negative staphylococci (CNS) to convert amino acids into volatile compounds and biogenic amines was investigated after 24h and 48 h of incubation in a rich medium (brain heart infusion). Volatile compounds were measured with static-headspace gas chromatography and mass spectrometry (SH-GC-MS); biogenic amine measurements were carried out with a newly developed method based on ultra-performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS). In total, 56 CNS strains from five different species were used, namely Staphylococcus carnosus, Staphylococcus epidermidis, Staphylococcus equorum, Staphylococcus saprophyticus, and Staphylococcus xylosus. With respect to the production of volatile compounds, the leucine-derived 3-methyl butanol was produced over time by most CNS strains, up to 52 muM for S. xylosus W1-1 after 48 h of incubation. The average production by strains of S. xylosus was significantly higher than for strains of S. carnosus, whereas strains of S. epidermidis turned out to be poor producers. Yet, differences between species were blurred to a large degree because of the high strain variability. A few strains also produced 3-methyl butanal on top of the amount that was already present in the medium background, although most CNS led to a decrease of this compound. Concerning biogenic amines, the average total concentrations per species remained below 100 muM after 48 h of incubation. The most abundant variant was 2-phenylethylamine (PEA), especially within S. carnosus (average of 65 muM after 48 h of incubation). Yet, some individual strains were able to produce higher concentrations, as found for the PEA production of 295 muM by S. epidermidis ATCC 12228 after 48 h of incubation. The insights obtained during this study indicate heterogeneity and are of importance in view of both starter culture development and the evaluation of a spontaneously established CNS microbiota in artisan-type meat fermentations" |
| Keywords: | Amino Acids/*metabolism Biogenic Amines/analysis Culture Media/chemistry Fermentation *Food Microbiology Meat Products/microbiology Staphylococcus/enzymology/*metabolism Tandem Mass Spectrometry Volatile Organic Compounds/analysis Biogenic amines Coagulas; |
| Notes: | "MedlineStavropoulou, Despoina Angeliki Borremans, Wim De Vuyst, Luc De Smet, Stefaan Leroy, Frederic eng Research Support, Non-U.S. Gov't Netherlands 2015/05/21 Int J Food Microbiol. 2015 Nov 6; 212:34-40. doi: 10.1016/j.ijfoodmicro.2015.04.048. Epub 2015 May 7" |
