INTRODUCTION
Current US regulations (Code of Federal Regulations 1998)
require enumeration of fecal coliform or Salmonellae prior to
land application of biosolids (treated sewage sludge). This
regulation specifies use of enumeration methods included in
Standard Methods for the Examination of Water and
Wastewater 18th Edition [American Public Health Association
APHA et al. 1992], or when analyzing for Salmonellae, a
cultural method developed by Kenner and Clark (1974). For Class A biosolids the regulation requires use of multiple-tube
fermentation techniques for fecal coliform or multiple-tube
enrichment techniques for Salmonellae followed by isolation
and biochemical and serologic confirmation. The difficulties
in completing the procedure for enumeration of Salmonellae
in biosolids and sludges has limited the use of this assay for
meeting regulatory requirements. Moreover, the time
required to confirm the presence of Salmonellae in a given
sample (up to 120 h) is considerably longer than the time
required to estimate the density of fecal coliforms (up to 72 h).
Analytical methods for Salmonella spp. which provide results
expeditiously may provide the means for more frequent and
routine monitoring of biosolid samples for these organisms.