USE OF THE CHROMOGENIC SUBSTRATE METHOD TO CALCULATE THE MOST PROBABLE NUMBER QUANTIFICATION OF THE COLIFORM GROUP FOUND WITHIN BOTTLED MINERAL WATER

Abstract

Microbiological quality of the bottled mineral water consumed in Curitiba, Paraná State, Brazil, was evaluated for total and fecal coliforms (Escherichia coli) throughout the method of chromogenic substrate. Six brands, codified with the letters A, B, C, D, E, and F, were analyzed. All brands presented no fecal coliforms while two samples showed presence of total coliforms. The samples were considered suitable for consumption under microbiological means. In Brazil, the current legislation only establishes as potability standard the absence of Escherichia coli, not referring to the presence of any other bacteria of the coliform group. The standards of potability specified by CODEX ALIMENTARIUS and the European Economic Community are more tight, considering the presence of coliforms in the mineral water as an indicative of inefficient sanitary cares and problems in the process operations and others that may modify the characteristic properties and their composition. The positive samples were submitted to the biochemical identification showing up the presence of Enterobacter gergoviae and Citrobacter freundi, in the sample A and of E. gergoviae and E. aerogenes in the sample B, considered total coliform microorganisms, confirming the previous result reached with the applied method.