The effect of adding freeze or heat-shocked Lactobacillus delbrueckii subsp. helveticus DSMZ 20082 + commercial starter (Lactococcus lactis subsp. cremoris, Lactococcus lactis subsp. lactis, Leuconostoc mesenteroides subsp. cremoris and Lactococcus lactis subsp. diacetilactis) to cheese milk (cow's and buffalo's milk 1:1 standardized to 3.5% fat) to accelerate Gouda cheese ripening and improve the quality compared with controls (cheese treated with commercial starter alone and cheese treated with commercial starter + viable cells of Lb. helveticus). Resultant cheese was then kept in the ripening room at 10-12ºC and 85-95% relative humidity for 3 months. Cheese samples were analyzed chemically, microbiologically, rheologically and organoleptically when fresh and after 30, 60 and 90 days of ripening. The obtained results indicated that the ripening indices (SٍN, SN/TN, soluble tyrosine & tryptophan and T.V.F.A contents); the proteolytic & lipolytic bacterial counts and sensory evaluation scores increased with the increase of ripening period. The cheese treated with freeze-shocked Lb. helveticus had the highest values of these parameters followed by cheese treated with heat-shocked Lb. helveticus compared with other treatments in all stages of ripening. Cheese treated with freeze or heat-shocked Lb. helveticus had more desirable texture along ripening and there was a reduction of 33% in the ripening period compared to other treatments. The patterns of free fatty acids and electrophoretic patterns in control cheese treated with commercial starter alone and cheese treated with freeze-shocked Lb. helveticus at 90 days showed higher levels of volatile fatty acids and higher number of bands of protein respectively in cheese treated with freeze-shocked Lb. helveticus than that of control cheese.