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Title: SIMPLE AND RAPID METHODS FOR DETECTING SALMONELLA ENTERITIDIS IN RAW EGGS

Author
item SEO, KUN-HO - FDA - WASHINGTON, D.C.
item Holt, Peter
item STONE, HENRY - USDA RET/ COLLABORATOR
item Gast, Richard

Submitted to: International Journal of Food Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/2/2002
Publication Date: 10/15/2003
Citation: SEO, K., HOLT, P.S., STONE, H., GAST, R.K. SIMPLE AND RAPID METHODS FOR DETECTING SALMONELLA ENTERITIDIS IN RAW EGGS. INTERNATIONAL JOURNAL OF FOOD MICROBIOLOGY. 2003. 87 139-144

Interpretive Summary: The Centers for Disease Control and Prevention estimates there were 300,000 cases of Salmonella serotype Enteritidis (SE) in 1997. Egg products were associated with many of the cases. To address this problem, many producers implemented flock surveillance of the SE situation at their facility. A rapid and simple method for detecting SE from poultry samples is critical for the effective implementation of such testing strategies. A lateral flo device for the detection of SE utilized in this study was manufactured by Neogen Corporation, Lansing, MI in collaboration with the author (PSH). This device is similar to the home pregnancy tests that are widely used at home by laypersons and is therefore very easy to use and understand. The thickness of the egg pools hinder the use of the devices so a simple procedure for extracting SE from the egg using oily acids was developed which enhanced the ability of the Neogen panel to detect SE at least 10-fold. The Neogen SE panel detected SE in 100% of egg pools supplemente with nutrient-rich broths and inoculated with SE, if the pools were first extracted with the oily acid. The simplicity of the above culture methodology coupled with its enhanced detection capability should make use of the Neogen panel an attractive procedure for laboratories lacking microbiology sophistication who want to conduct their own in-house egg testing.

Technical Abstract: The Centers for Disease Control and Prevention estimates there were 300,000 cases of Salmonella serotype Enteritidis (SE) in 1997. Egg products were associated with many of the cases. To address this problem, many producers implemented flock surveillance of the SE situation at their facility. A rapid and simple method for detecting SE from poultry samples is critical for the effective implementation of such testing strategies. A lateral flo device for the detection of SE utilized in this study was manufactured by Neogen Corporation, Lansing, MI. The test panel is a presumptive qualitative test system that detects only members of Group D1 Salmonella species. A series of studies were conducted to optimize the test procedure for raw eggs with different sample preparations. A novel antigen extraction method was developed for use with the test panel kit. The detection limit of the test panel kit was increased approximately 10-fold when the extraction method was used. Detection of SE was 100% in raw egg pools inoculated with 10 SE cells per ml of egg and incubated at a 1:10 ratio in buffered peptone water or tetrathionate brilliant green broth for 24 h at 37C. The developed lateral flow test kit could provide a simple, rapid, and inexpensive method for egg producers and processors to test specifically for Salmonella group D1 serovars, such as SE, in egg samples.