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Comparison of Upgraded Methods for Detecting Pathogenic Escherichia coli in Foods Using Centrifugation or Filtration
Korean J. Food Sci. An. 2017;37:799-803
Published online December 31, 2017
© 2017 Korean Society for Food Science of Animal Resources

Yukyung Choi1,2, Heeyoung Lee1,2, Soomin Lee1,2, Sejeong Kim1,2, Jeeyeon Lee1,2, Jimyeong Ha1,2, Hyemin Oh1,2, and Yohan Yoon1,2*

1Department of Food and Nutrition, Sookmyung Women’s University, Seoul 04310, Korea
2Risk Analysis Research Center, Sookmyung Women’s University, Seoul 04310, Korea
Correspondence to: Yohan Yoon
Risk Analysis Research Center, Sookmyung Women’s University, Seoul 04310, Korea
Tel: +82-2-2077-7585 Fax: +82-2-710-9479 E-mail: yyoon@sookmyung.ac.kr
Received May 23, 2017; Revised September 26, 2017; Accepted October 11, 2017.
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract
In the present study, centrifugation and filtration pretreatments were evaluated to decrease sample preparation time and to improve the sensitivity and specificity of multiplex polymerase chain reaction (PCR) for the detection of low levels of pathogenic Escherichia coli in various foods. Pathogenic E. coli (E. coli NCCP11142, E. coli NCCP14037, E. coli NCCP 14038, E. coli NCCP14039, and E. coli NCCP15661) was inoculated into pork, beef, and baby leafy vegetables at 1, 2, and 3 Log CFU/g. The samples were shaken 30 times (control), then centrifuged or filtered. DNA extracts from the samples were subjected to PCR using the PowerchekTM Diarrheal E. coli 8-plex Detection Kit. In the pork samples, no E. coli was detected in the control samples, while E. coli were detected in 100% of 3-Log CFU/g inoculated and centrifuged samples, and in 100% of 2 and 3-Log CFU/g inoculated, and filtered samples. In the beef samples, all control samples appeared to be E. coli-negative, while E. coli was detected in 50-75% of centrifuged samples, regardless of inoculated level, and in 100% of 2 and 3-Log CFU/g inoculated, and filtered samples. In baby leafy vegetables, E. coli were not detected in 25-50% of the control samples, while E. coli were detected in 0-25% of the centrifuged samples, and 75-100% of the filtered samples, depending on the inoculum amount. In conclusion, filtration pretreatment can be used to minimize sample preparation time, and improve the sensitivity and specificity of rapid detection of pathogenic E. coli in various foods.
Keywords : Escherichia coli, sample pretreatment, centrifugation, filtration, rapid detection, polymerase chain reaction


August 2018, 38 (4)