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Comparison of Real-Time PCR and Conventional Culture Method for Detection of Cronobacter spp. in Powdered Foods  

Chon, Jung-Whan (Department of Public Health, College of Veterinary Medicine, Konkuk University)
Song, Kwang-Young (Department of Public Health, College of Veterinary Medicine, Konkuk University)
Kim, Sun-Young (Department of Public Health, College of Veterinary Medicine, Konkuk University)
Hyeon, Ji-Yeon (Department of Public Health, College of Veterinary Medicine, Konkuk University)
Kim, Yun-Gyeong (Department of Public Health, College of Veterinary Medicine, Konkuk University)
Hwang, In-Gyun (Division of Microbiology, Korea Food and Drug Administration)
Kwak, Hyo-Sun (Division of Microbiology, Korea Food and Drug Administration)
Seo, Kun-Ho (Department of Public Health, College of Veterinary Medicine, Konkuk University)
Publication Information
Korean Journal of Microbiology / v.47, no.1, 2011 , pp. 87-91 More about this Journal
Abstract
The aim of this study was to compare the performance of conventional culture and real-time PCR for detection of Cronobacter spp. in powdered foods. Infant formula, baby food and Misugaru inoculated with Cronobacter were enriched in distilled water as first enrichment step, followed by incubating in Enterobacteriaceae enrichment (EE) broth as second enrichment step. A loopful of enriched sample was streaked onto Druggan-Forsythe-Iversen agar, followed by incubating at $37^{\circ}C$ for 24 h. One milliliter of the enriched distilled water and EE broth were used in real-time PCR assay. No statistical differences were observed in the number of positive samples between culture method and real-time PCR (p>0.05) in all types of food samples. The number of positives of real-time PCR was higher in the first enrichment media (distilled water) than the second enrichment media (EE broth), though there was no significant difference (p>0.05). It appears that some components of the second enrichment broth, EE broth, inhibit the reaction of real-time PCR. These results show that real-time PCR using a single enrichment with distilled water could be useful as an effective screening method for detection of Cronobacter while saving much time and labor compared to conventional culture method.
Keywords
Cronobacter spp.; culture method; infant formula; real-time PCR;
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