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United States Department of Agriculture

Agricultural Research Service

Title: Effect of Elevated Incubation Temperature (42 Degrees C) on the Multiplication and Rapid Detection of Salmonella Enteritidis in Egg Contents Pools.

item Gast, Richard
item Holt, Peter

Submitted to: Poultry Science Association Meeting Abstract
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 5, 2003
Publication Date: August 8, 2003
Citation: Gast, R.K., Holt, P.S. 2003. Effect Of Elevated Incubation Iemperature (42 Degrees C) On The Multiplication And Rapid Detection Of Salmonella Enteritidis In Egg Contents Pools. Poultry Science, 2003.V.82(Supplement 1) Abstract, p.53-54.

Technical Abstract: Detecting internal contamination of eggs with Salmonella enteritidis is essential for identifying laying flocks that could threaten public health. The most common strategy for such testing is to prepare pools of the contents of 10-20 eggs and to then incubate these pools at 25-37 degrees C to allow S. enteritidis multiplication before proceeding to a series of traditional bacteriological culturing steps. Supplementation with concentrated sources of nutrients can increase the rate of S. enteritidis growth in incubating egg pools. The present study sought to determine whether incubation of egg pools at an elevated temperature (42 degrees C) could further increase the rate of multiplication of S. enteritidis in order to allow the detection of contamination by a rapid method within a single day. Pools of 10 eggs were contaminated with approximately 10 cfu of S. enteritidis, supplemented with concentrated broth enrichment medium, and incubated at either 37 degrees C or 42 degrees C. Incubation of contaminated egg pools at 42 degrees C resulted in significantly higher S. enteritidis levels after 6, 8, 10, and 12 hours. However, incubation at 42 degrees C could only generate a mean S. enteritidis concentration of 16,000 cfu/ml within a single working day (8 hours), inadequate to support efficient detection by most rapid assays. Accordingly, detection of S. enteritidis contamination in egg pools by a rapid lateral flow immunodiffusion test was not achieved at a high frequency until 12 hours of incubation at 42 degrees C.

Last Modified: 4/19/2015
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