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Lab Divisions - Salmonella Lab

Poultry Farm Samples

The Salmonella Risk Reduction Program was created in the late 1980’s to help reduce the risk of egg associated human illness from Salmonella enteritidis. Environmental samples are collected from specific areas of each participating poultry farm at defined intervals. At the lab, each sample is screened for Salmonella enteritidis by a procedure involving selective enrichment, selective media and plate agglutination. All Salmonella enteritidis positive cultures are confirmed by the National Veterinary Services Laboratory (NVSL) and are immediately reported to the farm and to the state veterinarian.  The regulatory authorities are responsible for taking appropriate actions to ensure a safe food supply.

General salmonella suspect samples

All other diagnostic samples to be tested for salmonella use a procedure similar to the Salmonella Risk Reduction Program procedure, with less emphasis on S. enteritidis alone and more focus on culturing and identifying all serotypes.  If serotyping, phage typing or molecular sequencing is requested, isolates are sent to NVSL.

Summary of Salmonella Procedure

  • Selective enrichment in tetrathionate broth with added brilliant green and iodine
  • Streaked onto selective plates: brilliant green and XLT-4
  • Screened for Group D (suspect Salmonella enteritidis) with Salmonella O Antiserum Group D1 Factors 1,9,12
  • Suspect colonies from plates transferred to TSI and LIA slants
  • Suspect slants agglutinated with Salmonella O Antiserum Poly A-1& Vi and Salmonella O Antiserum Group D1 Factors 1,9,12
  • Negative samples are re-tested 5-7 days later
  • Group D positive samples sent to NVSL for confirmation of Salmonella enteritidis
  • Routine poultry environmental samples set up on Monday and Tuesday of each week
  • Emergency diagnostic samples set up immediately
  • Results can be expected within 14 business days of starting sample
  • Isolates needing serotyping and/or Salmonella enteritidis confirmation are sent to NVSL with a “rush” request.
  • Egg testing as required by the FDA can be accomplished within 10 days of receipt of samples.


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