We have investigated the capacities of Geotrichum candidum strains to
produce sulphides from methionine. This attribute is very important in cheese
technology because of the flavouring potential of sulphur compounds. A spectrophotometric
procedure using 5,5′-dithiobis(2-nitrobenzoic acid) to determine sulphides was
tested on a collection of G. candidum strains, and confirmed by gas
chromatography–mass spectrometry. The strains were distinguished on the basis of
their ability to produce methanethiol. Gas chromatography–mass spectrometry also
made it possible to identify other sulphides, such as dimethyl disulphide, dimethyl
trisulphide and dimethyl sulphide. Using sonicated cells, the specific production of
these four sulphides was studied in presence of L-[S-methyl-2H]methionine. Both
methanethiol and dimethyl sulphide were produced from methionine, but two
different pathways were used by G. candidum.