A novel approach to explain the inactivation mechanism of Escherichia coli employing a commercially avaiable peracetic acid

FLORES MARINA; LESCANO MAIA; BRANDI RODOLFO; CASSANO ALBERTO; LABAS MARISOL

WATER SCIENCE AND TECHNOLOGY

I W A PUBLISHING

Año: 2014 vol. 69 p. 358 - 363

0273-1223

Abstract: The chemical disinfection of Escherichia coli employing a commercial mixture of peracetic acid (PAA) was studied. For this purpose experiments were carried out using dilutions of the unmodified mixture, and the same composite but with hydrogen peroxide (HP) inhibited. Also, these results were compared to those previously obtained employing HP alone. It was found that the mixture is much more efficient than HP and PAA acting separately. Furthermore, it was found that PAA without hydrogen peroxide is much more efficient than HP alone. A feasible explanation is presented. The homolysis of peracetic acid would give raise to a chain reaction which generates a significant number of highly oxidizing radicals. An attacking scheme to bacteria in two stages is proposed, where the initial step, mainly caused by PAA, is very fast and eliminates some specific components of the bacteria that would otherwise inhibit the parallel action of hydrogen peroxide. Thereafter, the emergence of a potentiating synergetic action of the second oxidant seems to be immediately unveiled.