non-culturable state under environmental conditions. Viable, non-culturable E. coli O157:H7, which may be potentially infectious, would not be detected by culture methods but would be detected by DPCR. The ability of DPCR to detect dead cells or free DNA could be advantageous for some purposes. For example, DPCR could be useful in tracing the source of an outbreak to identify STEC in a sample regardless of whether it still contains culturable or viable cells.