The present work describes the ripening of eight quarters of raw milk Swiss Emmental cheese leaves 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 following parameters were measured and statistically compared: microbial composition (propionic bacteria, enteroccoci and facultative heterofermentative lactic acid bacteria), chemical composition (water, fat, total nitrogen, water soluble nitrogen, nonprotein nitrogen, ammonium, water soluble minerals, copper, volatile fatty acids, lactic citric and succinic acid, the ortho-phthaladehyde-, p-benzoquinone- and cadmium-ninhydrin-values, free amino acids as well as biogenic amines), rheological properties (penetration depth, deformation and force at fracture, force at 33% deformation), sensorial properties such as taste (sweet, salty, acidic and bitter), odour and flavour intensify as well as other quality criteria (eye formation, body structure and consistency as well as shelf-life). Inhibition of propionic acid fermentation and enterococci was observed after addition of L. Casei subsp. Casei with a reduction in the production of tyramine without any loss of flavour properties of this cheese variety