Evaluation of fecal coliform samples from Oakland Bay, Washington, using a new sanitation model

The study described in this article analyzed the current statistical procedure used by the National Shellfish Sanitation Program (NSSP) to manage opening and closing of conditionally approved shellfish harvest areas and identified a deficiency in the statistical analytical method used by NSSP. The authors propose a new statistical model to address this deficiency. Over 2,100 fecal coliform samples, collected by the Washington Department of Public Health from 15 shellfish stations in Oakland Bay, Washington, over 10 years from January 13, 2000, to December 9, 2009, were analyzed. The results suggest that the estimated 90th percentile criterion, which is currently used by NSSP, is not sufficient to protect the public from risks caused by consumption of biologically contaminated shellfish. To reduce this risk, the NSSP procedure should be augmented by applying the upper limit of the estimated 90th percentile of fecal coliform samples at the .05 significance level.