Laboratory Preparedness: A multi-laboratory validation of non-typhoidal salmonella in drinking and surface water

The EPA Water Laboratory Alliance (WLA) is a nationwide laboratory network that provides the capability to analyze water samples during a contamination event. In 2011 the WLA completed a multi-laboratory validation of non-typhoidal Salmonella. The multi-laboratory validation study involved ten commercial, utility, and public health laboratories from eight states. The Study included the analysis of PBS, drinking water, and surface water samples spiked with S. typhimurium BioBall® spikes. The results of this study were used to assess method performance (i.e., recovery and precision) across multiple laboratories and matrices, compare effect of holding time (0 - 8 hours after sample spiking, compared to 30 ± 1 hours after sample spiking), assess reproducibility of results from analyses of “blind” samples collected from each of two sites per matrix (drinking water and surface water), and develop QC acceptance criteria. This Method is needed to address gaps that exist within standardized methods for isolation and analysis of biological agents. Ultimately, the validation of this protocol enhances laboratory capabilities, improving the ability of the Water Sector to respond to water contamination incidents.