Rapid MPN-Qpcr Screening for Pathogens in Air, Soil, Water, and Agricultural Produce

Ezra Orlofsky, Maya Benami, Amit Gross, Michelle Dutt, Osnat Gillor

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


A sensitive, high-throughput, and cost-effective method for screening bacterial pathogens in the environment was developed. A variety of environmental samples, including aerosols, soil of various types (sand, sand/clay mix, and clay), wastewater, and vegetable surface (modeled by tomato), were concomitantly spiked with Salmonella enterica and/or Pseudomonas aeruginosa to determine recovery rates and limits of detection. The various matrices were first enriched with a general pre-enrichment broth in a dilution series and then enumerated by most probable number (MPN) estimation using quantitative PCR for rapid screening of amplicon presence. Soil and aerosols were then tested in non-spiked environmental samples, as these matrices are prone to large experimental variation. Limit of detection in the various soil types was 1-3 colony-forming units (CFU) g-1; on vegetable surface, 5 CFU per tomato; in treated wastewater, 5 CFU L-1; and in aerosols, >300 CFU mL-1. Our method accurately identified S. enterica in non-spiked environmental soil samples within a day, while traditional methods took 4 to 5 days and required sorting through biochemically and morphologically similar species. Likewise, our method successfully identified P. aeruginosa in non-spiked aerosols generated by a domestic wastewater treatment system. The obtained results suggest that the developed method presents a broad approach for the rapid, efficient, and reliable detection of relatively low densities of pathogenic organisms in challenging environmental samples.

Original languageEnglish
Article number303
JournalWater, Air, and Soil Pollution
Issue number9
StatePublished - 1 Sep 2015


  • Aerosol
  • Detection
  • MPN-qPCR
  • Nonspecific enrichment
  • Pathogen
  • Soil
  • Vegetable
  • Wastewater

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Chemistry
  • Ecological Modeling
  • Water Science and Technology
  • Pollution


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