Validación de métodos microbiológicos para cuantificar salmonella spp, presente en aguas tratadas con fotofenton

Abstract

A bstract: Advanced water disinfection processes have shown promising results when evaluated it by using the bacterial indicator Escherichia coli (E. coli). However, it has also shown that E. coli is less resistant to disinfection than other enteric bacteria such as Salmonella sp. This study proposes to evaluate the effectiveness of the plate count and NMP techniques against the gold standard DVC-FISH for the quantification of Salmonella sp. present in artificial water treated with the photo-fenton disinfection process. For the study, diagnostic tests were performed to calculate the sensitivity, specificity, and predictive values. The study found that the traditional plate count and NMP method, have a higher sensitivity when there is a high concentration of the bacteria. However, when the bacteria concentration is 10-2 dilutions, the sensitivity is 51% with the plate count technique and 100% with the NMP technique. In conclusion, the process of disinfection with Foto-fenton, the bacteria couldn´t be inactivated or totally inhibited because the bacteria had reversible damages that made them viable but it cannot be cultivated in the method of plate count. It couses high false negative result with this method, but in the NMP method, it became quantifiable whith lower concentrations of the bacteria.