The objectives of this study were to evaluate the detection of Listeria monocytogenes in different ready-to-eat foods using real-time PCR (RT-PCR). Various concentrations (100 to 105 CFU/ml) of L. monocytogenes ATCC 19115 were inoculated into ham, sausage, ground meat, processed milk, cheese, and infant formula. L. monocytogenes ATCC 19115 in the samples was then enumerated on Oxford agar, and DNA was extracted from the samples before and after incubation at 36°C for 4 h. A set of primers and hybridization probe designed in this study was then used to detect the pathogen. The standard curve was then prepared by plotting cycle threshold values for each dilution versus L. monocytogenes cell counts (log CFU). The specificity of the set of primers and hybridization probe was appropriate. A 4-h incubation at 36°C before DNA extraction produced optimum standard curves in comparison to the results for a 0-h incubation. Thus, a 4-h incubation at 36°C was applied for monitoring L. monocytogenes in collected food samples. To monitor L. monocytogenes in foods, 533 samples (ham, 129; sausage, 226; ground meat, 72; processed cheese, 54; processed milk, 42; and infant formula, 10) were collected from retail markets and from the step before pasteurization in plants. Of all 533 samples, 4 samples (0.8%) showed positive signals in RT-PCR. Two samples from hams (1.6%) and two samples from sausages (0.9%) were determined to be positive for L. monocytogenes at <100 CFU/g. The results indicate that the RT-PCR detection method with the set of primers and hybridization probe designed in this study should be useful in monitoring for L. monocytogenes in processed meat and milk products.
Skip Nav Destination
Article navigation
Research Article|
March 01 2014
Rapid Detection of Listeria monocytogenes by Real-Time PCR in Processed Meat and Dairy Products
EUN JEONG HEO;
EUN JEONG HEO
1Food Microbiology Division, Food Safety Evaluation Department, Ministry of Food and Drug Safety, Cheongwon 363-951, South Korea
Search for other works by this author on:
BO RA SONG;
BO RA SONG
1Food Microbiology Division, Food Safety Evaluation Department, Ministry of Food and Drug Safety, Cheongwon 363-951, South Korea
Search for other works by this author on:
HYUN JUNG PARK;
HYUN JUNG PARK
2Agro-Livestock & Fishery Products Policy Division, Ministry of Food and Drug Safety, Cheongwon 363-951, South Korea
Search for other works by this author on:
YOUNG JO KIM;
YOUNG JO KIM
3Livestock Products Standard Division, Ministry of Food and Drug Safety, Cheongwon 363-951, South Korea
Search for other works by this author on:
JIN SAN MOON;
JIN SAN MOON
4Veterinary Pharmaceutical Management Division, Animal and Plant Quarantine Agency, Anyang 430-757, South Korea
Search for other works by this author on:
SUNG HWAN WEE;
SUNG HWAN WEE
4Veterinary Pharmaceutical Management Division, Animal and Plant Quarantine Agency, Anyang 430-757, South Korea
Search for other works by this author on:
JIN-SEOK KIM;
JIN-SEOK KIM
5Research Center for Cell Fate Control and College of Pharmacy,
Search for other works by this author on:
YOHAN YOON
YOHAN YOON
*
6Department of Food and Nutrition, Sookmyung Women's University, Seoul 140-742, South Korea
* Author for correspondence. Phone: +82-2-2077-7585; Fax: +82-2-710-9479; E-mail: yyoon@sookmyung.ac.kr.
Search for other works by this author on:
J Food Prot (2014) 77 (3): 453–458.
Article history
Received:
July 30 2013
Accepted:
October 03 2013
Citation
EUN JEONG HEO, BO RA SONG, HYUN JUNG PARK, YOUNG JO KIM, JIN SAN MOON, SUNG HWAN WEE, JIN-SEOK KIM, YOHAN YOON; Rapid Detection of Listeria monocytogenes by Real-Time PCR in Processed Meat and Dairy Products. J Food Prot 1 March 2014; 77 (3): 453–458. doi: https://doi.org/10.4315/0362-028X.JFP-13-318
Download citation file: