title: Comparison of Culture, Conventional and Real-time PCR Methods for Listeria monocytogenes in Foods.
abstract: We compared standard culture methods as well as conventional PCR and real-time PCR for the detection of Listeria monocytogenes (L. monocytogenes) in milk, cheese, fresh-cut vegetables, and raw beef that have different levels of background microflora. No statistical differences were observed in sensitivity between the two selective media in all foods. In total, real-time PCR assay exhibited statistically excellent detection sensitivity (p<0.05) and was less time consuming and laborious as compared with standard culture methods. Conventional culture methods showed poor performance in detecting L. monocytogenes in food with high levels of background microflora, generating numerous false negative results. While the detection of L. monocytogenes in fresh cut vegetable by culture methods was hindered only by L. innocua, various background microflora, such as L. innocua, L. welshimeri, L. grayi, and Enterococcus faecalis appeared on the two selective media as presumptive positive colonies in raw beef indicating the necessity of improvement of current selective media. It appears that real-time PCR is an effective and sensitive presumptive screening tool for L. monocytogenes in various types of foods, especially foods samples with high levels of background microflora, thus complementing standard culture methodologies.
authors.affiliation: KU Center for Food Safety, College of Veterinary Medicine, Konkuk University, Seoul 143-701, Korea.
authors.forename: Dong-Hyeon
authors.initials: DH
authors.lastname: Kim
authors.affiliation: KU Center for Food Safety, College of Veterinary Medicine, Konkuk University, Seoul 143-701, Korea.
authors.forename: Jung-Whan
authors.initials: JW
authors.lastname: Chon
authors.affiliation: KU Center for Food Safety, College of Veterinary Medicine, Konkuk University, Seoul 143-701, Korea.
authors.forename: Hyunsook
authors.initials: H
authors.lastname: Kim
authors.affiliation: KU Center for Food Safety, College of Veterinary Medicine, Konkuk University, Seoul 143-701, Korea.
authors.forename: Hong-Seok
authors.initials: HS
authors.lastname: Kim
authors.affiliation: KU Center for Food Safety, College of Veterinary Medicine, Konkuk University, Seoul 143-701, Korea.
authors.forename: Dasom
authors.initials: D
authors.lastname: Choi
authors.affiliation: KU Center for Food Safety, College of Veterinary Medicine, Konkuk University, Seoul 143-701, Korea.
authors.forename: Young-Ji
authors.initials: YJ
authors.lastname: Kim
authors.affiliation: KU Center for Food Safety, College of Veterinary Medicine, Konkuk University, Seoul 143-701, Korea.
authors.forename: Jin-Hyeok
authors.initials: JH
authors.lastname: Yim
authors.affiliation: Livestock Product Standard and Veterinary Epidemiology Division, Animal, Plant and Fisheries Quarantine and Inspection Agency, Anyang 430-757, Korea.
authors.forename: Jin-San
authors.initials: JS
authors.lastname: Moon
authors.affiliation: KU Center for Food Safety, College of Veterinary Medicine, Konkuk University, Seoul 143-701, Korea.
authors.forename: Kun-Ho
authors.initials: KH
authors.lastname: Seo
keywords: Listeria monocytogenes; conventional PCR; culture method; profiling of false-positive colonies; real-time PCR