A comparative study of indicator bacteria present in ice and soda from Las Vegas food establishments

Microbial analysis has long been used as an indicator of water quality. Since the passing of the Safe Drinking Water Act in 1974, microbial standards have been strictly set by the Environmental Protection Agency (EPA) to ensure that the public health is protected from bacterial pathogens. The bacteriological quality of water generally deteriorates as it travels from water treatment facilities through the main distribution system and into private plumbing and distribution systems. For example, Heterotrophic Plate Count (HPC) values typically increase once the water has entered plumbing devices such as beverage vending machines. Upon reaching a private facility, the opportunity for bacterial growth and human contamination is present.;In this study used the EPA water quality standards were used as a reference to analyze ice and soda samples collected from local food establishments for the presence of heterotrophic and coliform bacteria. The samples were evaluated with respect to the U.S. drinking water standards as indicators of the quality of the ice and soda. The study provided important information regarding the quality of the ice and soda dispensed in Las Vegas food establishments. Of the samples analyzed in this study, 33.3% of ice samples and 55.6% of soda samples exceeded the EPA limits set for heterotrophic bacteria concentration for drinking water. Of the ice samples collected, 72.2% were positive for presumptive coliform bacteria presence, and 88.9% of the soda samples were positive for presumptive coliform presence. No statistical significance was observed between the concentration of heterotrophic bacteria in ice samples (median = 202 CFU/ml) and soda samples (median = 775 CFU/ml). However, the presumptive coliform bacteria data did show that the soda samples (median = 139 CFU/ml) had a significantly higher concentration when compared to the ice samples (median = 3 CFU/ml). The type of food establishment from which the samples were collected did not have a significant influence on the bacteriological quality of the ice and soda. The findings of this study provide important evidence that could have public health implications and may influence future studies related to bacterial contamination of beverages sold in the Las Vegas Valley.