Detection of Listeria monocytogenes in Salmon Using the Probelia Polymerase Chain Reaction System

2003 ◽  
Vol 66 (3) ◽  
pp. 436-440 ◽  
Author(s):  
JASON WAN ◽  
KERRYN KING ◽  
SANTINA FORSYTH ◽  
M. JOHN COVENTRY
Keyword(s):  
Polymerase Chain Reaction ◽  
New Zealand ◽  
Listeria Monocytogenes ◽  
Reaction System ◽  
Food Microbiology ◽  
Detection Sensitivity ◽  
Broth Culture ◽  
Chain Reaction ◽  
Pcr Method ◽  
Polymerase Chain

A validation was conducted on the performance of a commercially available polymerase chain reaction (PCR) kit (Probelia) in comparison with International Organization for Standardization (ISO) method 11290-1 (adopted as an Australian New Zealand Standard Method, AS/NZS 1766.2.16.1:1998) for the detection of Listeria monocytogenes in salmon samples. The validation was conducted following the guidelines of an Australian New Zealand Standard (Guide to Determining the Equivalence of Food Microbiology Test Methods, Part 1, Qualitative Tests, AS/NZS 4659.1:1999), which adopts an approach similar to that recommended by the Association of Analytical Communities Microbiology Method Validation Program for Performance Tested and Peer Verified Methods. The validation study involved the use of five cultures of L. monocytogenes, each challenged at a single level of inoculation into five different types of salmon samples. A total of 60 salmon samples (30 unchallenged and 30 challenged) were tested using both the PCR method and the ISO method. Results from this study indicated that the Probelia PCR method is equivalent to the ISO method. In addition, the detection sensitivity of the Probelia PCR system was determined as approximately 0.5 CFU per PCR assay (equivalent to 20 CFU/ml broth culture) for a pure culture of L. monocytogenes. The Probelia PCR method offers the advantage of detecting L. monocytogenes to genetic specificity within 48 to 50 h, whereas the ISO method requires 5 days for negative results with additional days for confirmed positive results by the use of other biochemical and cultural tests.

Combination of Immunomagnetic Separation and Polymerase Chain Reaction for the Simultaneous Detection of Listeria monocytogenes and Salmonella spp. in Food Samples

2001 ◽  
Vol 64 (11) ◽  
pp. 1744-1750 ◽  
Author(s):  
HSIEN-YEE HSIH ◽  
HAU-YANG TSEN
Keyword(s):  
Polymerase Chain Reaction ◽  
Listeria Monocytogenes ◽  
Simultaneous Detection ◽  
Meat Products ◽  
Immunomagnetic Separation ◽  
Food Samples ◽  
Chain Reaction ◽  
Salmonella Spp ◽  
Pcr Method ◽  
Polymerase Chain

A method that combined the immunomagnetic separation (IMS) technique and the multiplex polymerase chain reaction (PCR) method (i.e., the IMS-mPCR method) was developed for simultaneous detection of Listeria monocytogenes and Salmonella spp. in food samples. When only the multiplex PCR method was used, it was found that if cell numbers of each of the two target organisms (L. monocytogenes and Salmonella spp.) were above the detection limit, but differed by more than 2 logs—e.g., n × 107 to n × 104 or n × 106 to n × 103—the organism presenting the lower numbers might go undetected. Following the enrichment step with universal preenrichment (UP) broth, if an IMS method using equal quantities of anti-Listeria and anti-Salmonella immunomagnetic beads was performed prior to PCR, both pathogens could be detected unambiguously. Such results could be obtained for target organisms in food samples, such as milk, dairy, and meat products, if similar enrichment and IMS steps were performed prior to PCR.

Specificity of the BAX Polymerase Chain Reaction System for Detection of the Foodborne Pathogen Listeria monocytogenes

1998 ◽  
Vol 81 (4) ◽  
pp. 817-822 ◽  
Author(s):  
Diana Stewart ◽  
Steven M Gendel
Keyword(s):  
Polymerase Chain Reaction ◽  
Listeria Monocytogenes ◽  
Foodborne Pathogens ◽  
Foodborne Pathogen ◽  
Reaction System ◽  
Chain Reaction ◽  
Mixed Cell ◽  
Specificity And Sensitivity ◽  
Colony Forming Units ◽  
Polymerase Chain

Abstract The polymerase chain reaction (PCR) can be used for rapid and specific detection of foodborne pathogens. One commercial kit, the Qualicon BAX system uses PCR to detect Listeria monocytogenes in enrichment cultures derived from food and environmental samples. The specificity and sensitivity of the BAX system for detecting L. monocytogenes were characterized by using both pure and mixed cell cultures, and optimal conditions for production of cell lysates were determined. The BAX system was highly specific for L. monocytogenes, and no interference was seen in the presence of either other Listeria species or microbes from other genera. The assay detected L. monocytogenes at 105- 106 colony-forming units/mL. This sensitivity is adequate for detecting viable cells after enrichment but prevents false-positive signals from nonviable cells.

The fate of a genetically modifiedPseudomonasstrain and its transgene during the composting of poultry manure

2004 ◽  
Vol 50 (6) ◽  
pp. 415-421 ◽  
Author(s):  
J Guan ◽  
J L Spencer ◽  
M Sampath ◽  
J Devenish
Keyword(s):  
Polymerase Chain Reaction ◽  
Incubation Temperature ◽  
Genetically Modified ◽  
Chicken Manure ◽  
Detection Sensitivity ◽  
Plate Count ◽  
Chain Reaction ◽  
Nested Polymerase Chain Reaction ◽  
Soil Microcosms ◽  
Polymerase Chain

The fate of the genetically modified (GM) Pseudomonas chlororaphis strain 3732 RN-L11 and its transgene (lacZ insert) during composting of chicken manure was studied using plate count and nested polymerase chain reaction (PCR) methods. The detection sensitivity of the nested PCR method was 165 copies of the modified gene per gram of moist compost or soil. Compost microcosms consisted of a 100-g mixture of chicken manure and peat, whereas soil microcosms were 100-g samples of sandy clay loam. Each microcosm was inoculated with 4 × 1010CFU of P. chlororaphis RN-L11. In controlled temperature studies, neither P. chlororaphis RN-L11 nor its transgene could be detected in compost microcosms after incubation temperature was elevated to 45 °C or above for one or more days. In contrast, in the compost microcosms incubated at 23 °C, the target organism was not detected by the plate count method after 6 days, but its transgene was detectable for at least 45 days. In compost bins, the target organism was not recovered from compost microcosms or soil microcosms at different levels in the bins for 29 days. However, the transgene was detected in 8 of the 9 soil microcosms and in only 1 of the 9 compost microcosms. The compost microcosm in which transgene was detected was at the lower level of the bin where temperatures remained below 45 °C. The findings indicated that composting of organic wastes could be used to reduce or degrade heat sensitive GM microorganisms and their transgenes.Key words: composting, genetically modified Pseudomonas strain, transgene, polymerase chain reaction.

scholarly journals A Self-Contained Portable Polymerase-Chain-Reaction System Integrated with Electromagnetic Mini-Actuators for Bi-Directional Fluid Transport

2011 ◽  
Vol 27 (3) ◽  
pp. 357-364
Author(s):  
B. T. Chia ◽  
S.-A. Yang ◽  
M.-Y. Cheng ◽  
C.-W. Lin ◽  
Y.-J. Yang
Keyword(s):  
Polymerase Chain Reaction ◽  
Fluid Transport ◽  
Point Of Care ◽  
Reaction System ◽  
Thermal Characteristics ◽  
Pcr Amplification ◽  
Chain Reaction ◽  
Rapid Temperature ◽  
Small Footprint ◽  
Polymerase Chain

ABSTRACTIn this paper, the development of a portable polymerase chain reaction (PCR) device is presented. Integrating electromagnetic mini-actuators for bi-directional fluid transport, the proposed device, whose dimension is 67mm × 66mm × 25mm, can be fully operated with a 5V DC voltage. The device consists of four major parts: A disposable channel chip in which PCR mixture is manipulated and reacted, a heater chip which generates different temperature zones for PCR reaction, a linear actuator array for pumping PCR mixture, and a circuit module for controlling and driving the system. The advantages of the device include the rapid temperature responses associated with continuous-flow-type PCR devices, as well as the programmable thermal cycling associated with chamber-type PCR devices. The thermal characteristics are measured and discussed. PCR amplification is successfully performed for the 122 bp segment of MCF-7/adr cell line. Due to its small footprint, this self-contained system potentially can be employed for point-of-care (POC) applications.

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