Contribution of drinking water to the weekly intake of heterotrophic bacteria from diet in the United States

The goal of this study was to assess the relative contribution of heterotrophic bacteria from various sources in the normal diet of an average person in the United States, due to concerns regarding the potential health implications of such bacteria in household tapwater. A literature search was conducted to determine the concentration of heterotrophic plate count (HPC) bacteria in drinking water, as well as foods common to the American diet. Food items were also obtained in Tucson, AZ to further evaluate the consumption of HPC and total coliform bacteria. This was compared to a recent study on HPC bacteria in tapwater with and without POU devices mounted on the tap in Tucson, AZ households. It was determined that only 0.048-4.5% of the average consumer's total heterotrophic bacteria intake is derived from drinking water. Thus, HPC bacteria in drinking water do not represent a significant exposure of total HPC bacteria in the average diet of consumers in the United States.