Viabilidade de bactérias lácticas probióticas em leites fermentados comerciais

Abstract

Fermented milks are products obtained through the action of cultures of specific microorganisms and / or other lactic bacteria that, by their activity, contribute to the determination of the characteristics of the final product. Some of these microorganisms are considered probiotic because they confer health benefits when consumed in adequate amounts daily. These bacteria should remain viable throughout the shelf life of the product, bringing the benefits that are claimed in their packaging. The objective of this work was to evaluate the viability of probiotic lactic bacteria in three commercial fermented milks in order to certify that they contained the minimum quantity of these microorganisms alleged in their labels and / or required by Brazilian legislation. For this, total lactic acid bacteria were counted in plates by the depth plating technique, using MRS agar. The same agar was used as cover in order to create a microaerobic atmosphere. Also, pH and acidity parameters were determined. All fermented milk samples contained lactic acid bacteria in numbers above 107 cfu / mL, indicating suitability for the evaluated requirements. One of the three brands still made a claim to contain more microorganisms, in the order of 1010 cfu / mL, while another did not allege the presence of probiotic bacteria, but indicated the presence of live lactobacilli in the product. The acidity of the samples varied from 1.0% to 1.57% of lactic acid, according to the Brazilian legislation, the limits established are minimum of 0.6 and maximum of 2% of lactic acid being within the requirements of the legislation. Regarding pH, the observed values ranged from 3.5 to 4.0, range considered adequate for this type of product, and values close to those reported by other authors.