Viability and efects of the probiotic lactobacillus aracasei ssp aracasei in Chilean low-fat Gauda cheese. The objective of this study is to infer the survival of the probiotic Lactobacillus paracasei ssp paracasei added during the processing of low-fat Gouda cheese, during the maturation (21 days) and the commercialization (14 days), in order to see the influence that this organism has on the quality of the product. The treatments were: T1 (control): Gouda with normal fat content; T2: Low fat Gouda cheese (QGS) T3: QGS, with additional probiotic added with the initial culture; T4: QGS, with the probiotic added in the cooking of the curd. For the count of the probiotic, the methodology was used set forth by the American Public Health Association, (APHA), proteolysis by the method of soluble tyrosine in trichloroacetic acid (TCA), and the physical and chemical analysis using the methods standardized by the International Dairy Federation, and Chilean normative. The counts obtained were from 10(8) ufc/g y 10(7) ufc/g in the cheeses that had the probiotic additive (T3 and T4, respectively) close to the level of innocuous (10(8) ufc/g) during the study period of 35 days. The proteolysis incremented normally, and was the same in all of the treatments during the 35 days studied. The treatments with fat-reduction presented approximately, 31% less fat than the control treatment, and also higher moistness. Within the treatments, there was no evidence of taste and general feel; in turn the cheeses with the reduction of fat resulted firmer, less cohesive, than the control, and with similar elasticity.