Natural preservatives are widely used in the food industry since they have the ability to preserve or to be an antioxidant, but with the great difference that they are not harmful to health. Garlic with its compounds become a preservative agent, therefore, the objective of the research was to evaluate the effect of garlic extract (Allium sativum) as a preservative in a kefir-type fermented milk beverage. A completely randomized design was used where C (control) presented the percentages of natural kefir; T1 1Lt/ 3mlA; T2 1Lt/ 5mlA; T3 1Lt / 7mlA with three treatments and three replicates. Garlic extraction was carried out by a mechanical method which used a KM grater which consists of generating friction on a surface with sharp holes to separate the fibers into particles, colorimetry analysis was performed with a Konica Minolta CR-400 colorimeter, a viscosity analysis using a rotational viscometer and a hedonic scale of 7 points sensory analysis, the data were processed in the Minitab program, ANOVA and Dunnet. It was determined that there was a significant difference in the useful life of the product with respect to fungi, yeasts and mesophiles. In conclusion, results showed that the inclusion of 3ml, 5ml and 7ml of extract prolonged the shelf life without the presence of Coliforms and E. coli, reaching a durability of 21 days, however, at a higher concentration of garlic, acceptance decreased. The most widely accepted products in terms of color, odor, flavor, texture and general appearance parameters were treatments C (control) and T2. It is concluded that the inclusion of garlic extract had an antimicrobial effect in the production of milk kefir.