Effectiveness of Low Thermal Destruction on Drinking Water Contain Enteropathogenic Bacteria Isolated from Wellspring at Mojo Village Lumajang Regency-Indonesia

Abstract

Thermal processes, such as pasteurization are a component of strategy to ensure microbiological safety and food preservation. The objectives of this study were to evaluate the enteropathogenic bacteria population of Mojo wellspring and determine the effectiveness of low thermal destruction for water drinking contain enteropathogenic bacteria (Salmonellasp. and Eschericia colisp) indigenous Mojo wellspring. Population of enterophatogenic bacteria were determined by using Salmonella Chromogenic Agar (SCA) and Enteric Hectoin Agar (HEA). SCA resulted blue colony for E. coli and magentha or violet colony for Salmonella. While HEA resulted orange colony for E. coli and green for Salmonella. Thermal destruction used heating treatment at 70 o o o C temperature for 1 minute or 2 minutes. Effectiveness of destruction based on the value of the destruction percentage and the coefficient of destruction (k value). The calculation equation was used to determine the destruction percentage of bacteria cell. The equation was percentage of the dead bacteria population divided with the initial bacterial population. The k value obtained using the equation was k = (ln No – ln Nt)/t. The result showed that the highest destruction was heating treatment at 90 C, 80 C and 90 C temperature for 2 minutes. The percentage of destruction were 83.19% for E. coli and 74.78% for Salmonella, while k value were respectively 0,89 and 0,69.