Comparison of EB and Fraser Enrichment Broths for the Detection of Listeria spp. and Listeria monocytogenes in Raw-Milk Dairy Products and Environmental Samples

1996 ◽  
Vol 59 (11) ◽  
pp. 1172-1175 ◽  
Author(s):  
GEERTRUI M. VLAEMYNCK ◽  
RENAAT MOERMANS
Keyword(s):  
Listeria Monocytogenes ◽  
Dairy Products ◽  
Raw Milk ◽  
Chain Reaction ◽  
Enrichment Broth ◽  
Selective Enrichment ◽  
Isolation Frequency ◽  
Detection And Identification ◽  
Significant Difference ◽  
Polymerase Chain

This study is a comparison of the isolation frequency of Listeria spp. and Listeria monocytogenes from selected naturally contaminated dairy products, especially soft smear-ripened cheeses from raw milk and samples of feces and rinse samples from the udder taken on the farm, by using an enrichment broth (EB) recommended by the International Dairy Federation and the U.S. Food and Drug Administration (IDF and FDA) or Fraser broth as the selective enrichment. Detection and identification were carried out according to the IDF protocols and a polymerase chain reaction technique. Listeria spp. were detected in 39.8% of the 570 samples while 15.3% were positive for L. monocytogenes. For cheese and curd samples, Fraser enrichment broth gave a statistically significant higher recovery for all Listeria spp. (26 to 21 %) as well as for L. monocytogenes in particular (9 to 1.4%). For raw milk and samples taken from feces and the udder rinse no significant difference was found between EB and Fraser broth. A combination of both enrichments resulted in an increase of recovery over all matrices by 15%.

Detection of Thermophilic Campylobacter spp. in Blood-Free Enriched Samples of Inoculated Foods by the Polymerase Chain Reaction

2000 ◽  
Vol 63 (3) ◽  
pp. 299-303 ◽  
Author(s):  
RICHARD L. THUNBERG ◽  
TONY T. TRAN ◽  
MARK O. WALDERHAUG
Keyword(s):  
Polymerase Chain Reaction ◽  
Dna Extraction ◽  
Raw Milk ◽  
Extraction Techniques ◽  
Chain Reaction ◽  
Pcr Assay ◽  
Enrichment Broth ◽  
Thermophilic Campylobacter ◽  
Polymerase Chain ◽  
Campylobacter Spp

The detection of thermophilic Campylobacter spp., as represented by Campylobacter jejuni, by the polymerase chain reaction (PCR) was investigated and compared with the selective agar isolation (SAI) method. Stationary-phase cultures of C. jejuni were inoculated into either blood-free enrichment broth (BFEB) or BFEB that contained 10% broccoli, crabmeat, mushroom, raw milk, and raw oyster rinses. Following a 48-h enrichment period, aliquots of food test portions were removed for simultaneous analysis by PCR and SAI. It was determined that the presence of charcoal and iron in the enrichment broth interfered with the PCR assay. Therefore, three DNA extraction techniques were developed and evaluated using a 16S rRNA primer pair in the PCR assay. The 50% end point (DL50) values (determined upon six initial C. jejuni spiking levels) were used to assess the frequency of isolation utilizing PCR versus SAI for the detection of this organism in the enrichment matrices. There were virtually no differences in detection of C. jejuni among enriched samples analyzed by PCR and SAI. Mean DL50 values (n = 3) for plain BFEB, broccoli, crabmeat, mushroom, raw milk, and raw oyster were, respectively, 0.02 (PCR) versus 0.01 (SAI), 0.01 versus 0.06, 0.07 versus 0.04, 0.03 versus 0.08, 0.01 versus 0.01, and 0.01 versus 0.01 CFU/5 g food. Significant variability in the detection limit of C. jejuni by PCR in the food enrichments was observed among DNA extraction techniques. Using 48-h enrichment cultures followed by PCR analysis could save 1 day of the time required for the presumptive identification of C. jejuni in suspected foods.

Rapid Detection and Identification of Lactobacillus spp. in Dairy Products by Using the Polymerase Chain Reaction

1996 ◽  
Vol 59 (10) ◽  
pp. 1031-1036 ◽  
Author(s):  
MARYANNE DRAKE ◽  
CHRISTOPHER L. SMALL ◽  
KEMET D. SPENCE ◽  
BARRY G. SWANSON
Keyword(s):  
Polymerase Chain Reaction ◽  
Dairy Products ◽  
Lactobacillus Helveticus ◽  
Lactobacillus Delbrueckii ◽  
Lactobacillus Species ◽  
Chain Reaction ◽  
Bacterial Dna ◽  
Detection And Identification ◽  
Polymerase Chain ◽  
Species Specific

Species-specific primers for use in the polymerase chain reaction (PCR) were designed to differentially amplify DNA from the common dairy lactobacillus species Lactobacillus casei, Lactobacillus delbrueckii, Lactobacillus helveticus, and Lactobacillus acidophilus. A method for rapid extraction of bacterial DNA from dairy products was developed. The sensitivity of bacterial DNA extraction from food and subsequent amplification by PCR was 100 cells total. Lactobacillus DNA was extracted and identified from commercial yoghurts, acidophilus milk, and cheeses. The methodology allows the presumptive identification of dairy lactobacilli in less than 6 hours.

Incidence and Polymerase Chain Reaction Assay of Listeria monocytogenes from Raw Milk in Gyeongnam Province of Korea

2002 ◽  
Vol 65 (1) ◽  
pp. 111-115 ◽  
Author(s):  
KWANG-SOO HA ◽  
SEON-JA PARK ◽  
SOOK-JAE SEO ◽  
JUNG-HYUN PARK ◽  
DUCK-HWA CHUNG
Keyword(s):  
Polymerase Chain Reaction ◽  
Listeria Monocytogenes ◽  
Raw Milk ◽  
Food Samples ◽  
Chain Reaction ◽  
Pcr Assay ◽  
Biochemical Tests ◽  
Milk Samples ◽  
Polymerase Chain ◽  
Pcr Assays

A total of 50 raw milk samples from Gyeongnam Province of Korea were examined for the incidence of Listeria monocytogenes between July 1998 and August 1998. L. monocytogenes isolated by biochemical test was confirmed by polymerase chain reaction (PCR) with two sets of primers designed from the invasion-associated protein (iap) gene. After standard PCR with external primers, the amplified DNA was confirmed by a second round of PCR with internal primers (nested PCR). Both the external and internal primers generated 468-bp and 287-bp products, respectively. Only one (G9 strain) of the three suspect samples that tested positive in biochemical tests for L. monocytogenes from 50 raw milk samples was also PCR positive. Following this procedure, PCR-positive G9 strain was confirmed by Southern blot using the 287-bp internal iap probe again. The detection limit of G9 strain by standard PCR assay was as few as 102 cells, equivalent to approximately 1 pg of L. monocytogenes DNA. These PCR assays may be useful for novel detection as well as rapid confirmation for L. monocytogenes from food samples and the field.

scholarly journals Isolasi dan Identifikasi Bakteri Listeria monocytogenes dari Susu Sapi Segar di Kabupaten Enrekang Sulawesi Selatan

2018 ◽  
Vol 5 (2) ◽  
pp. 57-65
Author(s):  
Kusumandari Indah Prahesti ◽  
Ni Luh Putu Ika Mayasari ◽  
Ratmawati Malaka ◽  
Farida Nur Yuliati ◽  
Fachriyan Hasmi Pasaribu
Keyword(s):  
Polymerase Chain Reaction ◽  
Listeria Monocytogenes ◽  
Chain Reaction ◽  
Enrichment Broth ◽  
Selective Agar ◽  
Polymerase Chain

Listeria monocytogenes merupakan bakteri patogen yang dapat menginfeksi manusia melalui bahan pangan sehingga menimbulkan penyakit listeriosis. Wabah listeriosis terjadi akibat konsumsi bahan pangan yang terkontaminasi L. monocytogenes, di antaranya daging, susu, dan produk susu. Serotipe bakteri L. monocytogenes dikaitkan dengan kasus wabah epidemik dan sporadik listeriosis pada manusia. Penelitian ini bertujuan untuk mengisolasi L. monocytogenes dari susu sapi segar di Kabupaten Enrekang Sulawesi Selatan, melakukan analisis karakteristik molekuler, dan menentukan serotipe isolat bakteri L. monocytogenes yang diperoleh. Sebanyak 107 sampel susu diperoleh dari lima kecamatan di Kabupaten Enrekang dan dikumpulkan menjadi 31 sampel pool, kemudian dilakukan isolasi dan identifikasi bakteri. Tahap pengayaan dilakukan dengan media Listeria enrichment broth (LEB) kemudian dilakukan kultur pada media Listeria selective agar base (LSA), dilanjutkan dengan uji biokimiawi. Isolat bakteri L. monocytogenes yang diperoleh dikonfirmasi dengan polymerase chain reaction (PCR) dan dilakukan pengurutan oligonukleotida. Identifikasi serotipe dilakukan dengan PCR multipleks. Hasil menunjukkan bahwa sebanyak 21 isolat merupakan bakteri L. monocytogenes dan analisis pengurutan oligonukleotida menunjukkan bahwa isolat yang diperoleh memiliki kemiripan sebesar 99% dengan strain L. monocytogenes yang terdapat pada basis data GenBank. Identifikasi serotipe menunjukkan bahwa keseluruhan isolat termasuk dalam serogrup 2, yaitu serotipe 1/2c dan 3c.

Detection and identification of Candida spp. in human serum by LightCycler® real-time polymerase chain reaction

2008 ◽  
Vol 60 (3) ◽  
pp. 263-271 ◽  
Author(s):  
Catherine Dunyach ◽  
Sébastien Bertout ◽  
Cécile Phelipeau ◽  
Pascal Drakulovski ◽  
Jacques Reynes ◽  
...  
Keyword(s):  
Polymerase Chain Reaction ◽  
Human Serum ◽  
Real Time ◽  
Chain Reaction ◽  
Candida Spp ◽  
Detection And Identification ◽  
Polymerase Chain

scholarly journals Occurrence of toxigenic Escherichia coli in raw milk cheese in Brazil

2007 ◽  
Vol 59 (2) ◽  
pp. 508-512 ◽  
Author(s):  
B.R. Paneto ◽  
R.P. Schocken-Iturrino ◽  
C. Macedo ◽  
E. Santo ◽  
J.M. Marin
Keyword(s):  
Escherichia Coli ◽  
Polymerase Chain Reaction ◽  
Antimicrobial Agents ◽  
Raw Milk ◽  
Diffusion Method ◽  
Chain Reaction ◽  
Disk Diffusion Method ◽  
E Coli ◽  
Polymerase Chain ◽  
Raw Milk Cheese

The occurrence of toxigenic Escherichia coli in raw milk cheese was surveyed in Middle Western Brazil. Fifty samples of cheese from different supermarkets were analyzed for E.coli. The isolates were serotyped and screened for the presence of verotoxigenic E. coli (VTEC) and enterotoxigenic E. coli (ETEC) by Polymerase Chain Reaction (PCR). The susceptibility to thirteen antimicrobial agents was evaluated by the disk diffusion method. E.coli were recovered from 48 (96.0%) of the samples. The serogroups identified were O125 (6.0%), O111 (4.0%), O55 (2.0%) and O119 (2.0%). Three (6.0%) and 1(2.0%) of the E.coli isolates were VTEC and ETEC, respectively. Most frequent resistance was observed to the following antimicrobials: cephalothin (60.0%), nalidixic acid (40.0%), doxycyclin (33.0%), tetracycline (31.0%) and ampicillin (29.0%).

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