Table 4.

Detection limits of host-specific genetic markers and fecal coliformsa

Source of DNADetection limit (g of dry feces/liter)
HF8 clusterCF123 clusterCF151 clusterFecal coliforms
Cow feces AND2.8 × 10−7 2.8 × 10−5 2.8 × 10−7
Cow feces BND3.6 × 10−6 3.6 × 10−5 3.6 × 10−6
Sewage1.4 × 10−6 NDND1.4 × 10−7
• a Results are from dilution assays using either cow feces or raw sewage. Each cow sample combined feces from four cows. The sensitivity of detection of cow feces was measured twice, with two independent samples (A and B). Sewage dilutions were not replicated. Results for detection of the genetic markers are from two rounds (25 cycles each) of PCR. ND, not determined.