Evaluación antimicrobiana del extracto de la guayaba (Psidium guajava L) en el queso fresco.

Abstract

The objective of this study was to evaluate the use of guava extract (Psidium guajava l), obtained by percolation process, as an antimicrobial in fresh cheese. Three different extracts from different parts of the guava (bark, fruit and leaves) were added to the fresh cheese production process. Physicochemical measurements were made (pH, acidity, total solids, fat and protein), where significant differences were found for pH level and total solids content, and a sensory evaluation (odor, color, flavor and texture) using a hedonic scale, where the control treatment obtained the best scores between 4 and 5 points for the different parameters. The efficacy against Enterobacteriaceae, E. coli, Staphylococcus aureus, Listeria monocytogenes, Salmonella and fecal coliforms was studied against a control treatment. A completely randomized design (CRD) was applied with four replicates per treatment where the size of the experimental unit was 500g. The results were evaluated by means of microbiological analysis after the fresh cheese was made, where it was observed that the addition of 5% of the extracts managed to maintain the microbial load below the limits allowed by regulatory standards; in determining the microbiological shelf life of the fresh cheese, it was obtained that it is up to 7 days and sensorially up to 14 days. An economic analysis was also carried out, where the cost benefit was $ 1.25. It is concluded that the application of the extracts was able to maintain the microbial load within the levels of acceptability of the regulatory standards. Further studies on the application of plant extracts in foods with antimicrobial power are recommended.