Evaluation of solid-phase microextraction for analysis of volatile metabolites produced by staphylococci

The evaluation of solid-phase microextraction (SPME) for analysis of flavor compounds produced by bacteria has been studied. First, it was necessary to determine the optimal conditions to extract the different volatile compounds in dilute aqueous solutions. For this, the effects of salt, headspace, and liquid samplings and two coating phases [poly(dimethylsiloxane) (PDMS) and poly(acrylate) (PA)] were tested. The addition of salt enhanced SPME absorption of all the compounds. Ethyl ester was better extracted in liquid sampling with PDMS phase, whereas all of the other compounds were better extracted in headspace sampling at 80 degrees C with PA phase. The SPME technique was applied to the analysis of bacterial metabolites. It has been shown that Staphylococcus xylosus (16) and Staphylococcus carnosus (833) were able to produce esters and to catabolize leucine and that S. carnosus (833) limited the oxidation of free fatty acids.