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ARS Home » Southeast Area » Athens, Georgia » U.S. National Poultry Research Center » Poultry Microbiological Safety and Processing Research Unit » Research » Publications at this Location » Publication #313646

Title: Semi-quantitative method to estimate levels of Campylobacter

item Cox Jr, Nelson
item Cosby, Douglas
item WILSON, JENNA - University Of Georgia
item MCCLENDON, BEVERLY L - University Of Georgia
item Berrang, Mark

Submitted to: International Association for Food Protection
Publication Type: Abstract Only
Publication Acceptance Date: 3/20/2015
Publication Date: 7/25/2015
Citation: Cox Jr, N.A., Cosby, D.E., Wilson, J.L., Mcclendon, B., Berrang, M.E. 2015. Semi-quantitative method to estimate levels of Campylobacter. International Association for Food Protection. July 25-28, 2015. Portland, Oregon. 78(Suppl A):240.

Interpretive Summary:

Technical Abstract: Introduction: Research projects utilizing live animals and/or systems often require reliable, accurate quantification of Campylobacter following treatments. Even with marker strains, conventional methods designed to quantify are labor and material intensive requiring either serial dilutions or MPN procedures to estimate the numbers of Campylobacter in ceca. Purpose: The objective of this study was to devise an economical method which could accurately estimate the colony forming units per gram (CFU/g) of Campylobacter in the ceca of chicks. Methods: Day old chicks, housed in isolation units, were gavaged with a marker Campylobacter coli (CcGR), euthanized at 7 or 14 days and the ceca aseptically removed. All cecal samples were diluted 1:3 (w:v) in Tecra Broth (TB) and stomached for 60 s. CcGR recovery was conducted on Campy Cefex agar plates w/ 200 ppm gentamicin using a semi-quantitative method (SQM) previously used for Salmonella and by enumeration. Ceca were obtained from a local processing plant, divided into three aliquots and inoculated with a known CFU of the CcGR at three levels. The ceca and inoculum were weighed, 3 times the volume of TB added and then enumerated by both the SQM and a serial dilution procedure. Results: The SQM was comparable to the conventional enumeration method in 20/20 7-day and 19/20 14-day old broiler chicks. In addition to the bird study, a controlled experiment verified the reliability of the SQM. With inoculated ceca using three levels of CcGR (101, 103, and 105 CFU/g), the SQM showed no statistical difference (P>0.0 5 by paired t-test) from the CFU/g of inoculated cecal material and was more accurate than the standard method to predict the inoculated number of cells. Significance: This SQM provides researchers with an accurate, inexpensive and useful method to enumerate Campylobacter marker strains utilized in research studies.