Parâmetros de qualidade e estudo do método de disco-difusão para determinação da atividade antimicrobiana de águas sanitárias

Abstract

The sodium hypochlorite is used for many purposes and routinely found in all brazilian homes about the designation of bleach, with characteristics that may be harmful for humans, such as skin and eye burns, especially in high concentrations. Therefore, it is essential to have a legislation that can guarantee the quality of these products through the evaluating variables related to the effectiveness, safety of application and quality assurance of these product. Thus, the present work aims to analyze the physico-chemical quality of ten commercial bleach brands, as well as to study the disc diffusion method to determine their antimicrobial activity. For determination the physico-chemical quality were realized pH analyze and determination of active chlorine content. In general, it was found that the bleach brands presented pH values ranging from 12.2 to 12.7, in accordance with the defined by the legislation. In relation of the active chlorine content, two samples presented values higher those defined by legislation, which is 2.0% to 2.5% w / w, and one sample with a value below the established. Changes were made in the conduction of the disk diffusion method that allows a better determination of the antimicrobial activity of bleach. This is because the results shown in nine marks occurred only reduction of the microbial population next of the disc, when the expected would be formation of an inhibition halo.