EVALUATION OF SOLID-PHASE MICROEXTRACTION FOR ANALYSIS OF VOLATILE METABOLITES PRODUCED BY STAPHYLOCOCCI

The evaluation of solid-phase microextraction (SPME) for analysis of f lavor compounds produced by bacteria has been studied. First, it was n ecessary 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 add ition of salt enhanced SPME absorption of all the compounds. Ethyl est er was better extracted in liquid sampling with PDMS phase, whereas al l of the other compounds were better extracted in headspace sampling a t 80 degrees C with PA phase. The SPME technique was applied to the an alysis of bacterial metabolites. It has been shown that Staphylococcus xylosus (16) and Staphylococcus carnosus (833) were able to produce e sters and to catabolize leucine and that S. carnosus (833) limited the oxidation of free fatty acids.