The present work describes the ripening of eight raw milk Swiss Emmental cheese leaves, quarters of which were packaged at 3 months in a plastic sheet. The leaves were manufactured with and without addition of L. Casei subsp. Casei to the usual starter cultures. Samples were taken at 3, 6, 9 and 12 months of ripening. The changes in content of 38 volatile neutral components (primary and secondary alcohols, mono- and diketones, aldehydes, esters, aliphatic and aromatic hydrocarbons and sulfur compounds) were measured using dynamic GC-headspace analysis. Except for all aldehydes produced from a beta-oxidation of unsaturated fatty acids and hydrocarbons whose concentration significantly decreased, most volatile components showed an increase in content during ripening. Addition of L. Casei subsp. Casei to the usual starter culture rued for Swiss Emmental cheese showed statistically significant differences for production of ethanol, propanol-1, 2- and 3-methylbutanol-1,2,3-pentandione, 2- and 3-methylbutanal, as well as propionic acid propylester. Of the volatiles established as flavour compounds of Swiss Emmental cheese the analytical procedure used here was sufficient to detect heptanone-2, 2,3-butandione, 2- and 3-methylbutanal, ethyl butyrate and ethyl caproate
