HS-SPME characterization of volatile compounds and microbiological parameter in milk tainted with off-flavour

Changes in volatile compounds profile and microbiological parameters of raw and UHT milk samples tainted with offflavour were investigated in this preliminary study. Volatile compounds were extracted and identified using HeadspaceSolid-Phase Microextraction - Gas Chromatography/Mass Spectrometry (HS-SPME-GC/MS). Microbiological analyses were done in order to determine the milk quality of milk samples. Microbiological data were then tentatively correlated with GC/MS data. Higher concentrations of ketones (2-propanone, 3-hydroxy-2-butanone and 2,3-butanedione), esters (acetic acid ethyl ester and butanoic acid ethyl ester) and sulphur compounds (dimethyl sulfide, dimethyl sulfone and hydrogen sulfide) were found in raw milk samples with high amount of gram-negative psychrotrophs bacteria (GNP).