BIOTECON Diagnostics foodproof®Listeria monocytogenes Detection Kit, 5′ Nuclease in Combination with the foodproof ShortPrep II Kit

2012 ◽  
Vol 95 (1) ◽  
pp. 92-99 ◽  
Author(s):  
Benjamin Junge ◽  
Cordt Grönewald ◽  
Kornelia Berghof-Jäger

Abstract A method was developed for the detection of Listeria monocytogenes in food. The method is based on real-time PCR using hydrolysis probes (5′ Nuclease). This advanced PCR method was designed to reduce the time necessary to achieve results from PCR reactions and to enable the user to monitor the amplification of the PCR product simultaneously, in real-time. After DNA isolation using the BIOTECON food proof® ShortPrep II Kit designed for the rapid preparation of L. monocytogenes DNA for direct use in PCR, the real- time detection of L. monocytogenes DNA is carried out using the food proof Listeria monocytogenes Detection Kit. The kit provides primers and hydrolysis probes for sequence-specific detection, convenient premixed reagents, and controls for reliable interpretation of results. For the internal comparison study, three different foods (soft cheese, coalfish, and smoked ham) were analyzed, chosen from the 15 food groups recommended by the AOAC Research Institute for detection of L. monocytogenes. From each food, 20 samples were inoculated with a low level (1–10 CFU/25 g) and 20 samples with a high level (10–50 CFU/25 g) of L. monocytogenes. Additionally, five nonspiked samples were prepared from each food. Depending on the matrix, the food samples were examined with the test kits and compared with the cultural methods according to the U.S. Food and Drug Administration's Bacteriological Analytical Manual or the U.S. Department of Agriculture/Food Safety and Inspection Service Microbiology Laboratory Guidebook.

2011 ◽  
Vol 94 (6) ◽  
pp. 1846-1852
Author(s):  
Benjamin Junge ◽  
Cordt Grönewald ◽  
Kornelia Berghof-Jäger

Abstract The method describes the detection of Escherichia coli O157 in food. The method is based on real-time PCR using hydrolysis probes (5′ Nuclease). This advanced PCR method was designed to reduce the time necessary to achieve results from PCR reactions and enable the user to monitor the amplification of the PCR product simultaneously in real time. After DNA isolation using the BIOTECON foodproof® ShortPrep II Kit designed for the rapid preparation of E. coli O157 DNA for direct use in PCR, the real-time detection of E. coli O157 DNA is carried out using the foodproof E. coli O157 Detection Kit. The kit provides primers and hydrolysis probes for sequence-specific detection, convenient premixed reagents, and controls for reliable interpretation of results. For repeatability studies three different foods (egg salad, large bockwurst/frankfurter, and apple juice) were analyzed, chosen from the 15 food groups recommended by the AOAC Research Institute for E. coli O157 detection. From each food, 20 samples were inoculated with a low level (1–10 CFU/25 g) and 20 samples with a high level (10–50 CFU/25 g) of E. coli O157. Additionally, five nonspiked samples were prepared from each food. Depending on the matrix, the food samples were examined with the test kits and compared with the cultural methods according to the U.S. Food and Drug Administration Bacteriological Analytical Manual or the U.S. Department of Agriculture/Food Safety and Inspection Service Microbiology Laboratory Guidebook.


2014 ◽  
Vol 77 (2) ◽  
pp. 180-188 ◽  
Author(s):  
PINA M. FRATAMICO ◽  
JAMIE L. WASILENKO ◽  
BRADLEY GARMAN ◽  
DANIEL R. DeMARCO ◽  
STEPHEN VARKEY ◽  
...  

The “top-six” non-O157 Shiga toxin–producing Escherichia coli (STEC) serogroups (O26, O45, O103, O111, O121, and O145) most frequently associated with outbreaks and cases of foodborne illnesses have been declared as adulterants in beef by the U.S. Department of Agriculture Food Safety and Inspection Service (FSIS). Regulatory testing in beef began in June 2012. The purpose of this study was to evaluate the DuPont BAX System method for detecting these top six STEC strains and strains of E. coli O157:H7. For STEC, the BAX System real-time STEC suite was evaluated, including a screening assay for the stx and eae virulence genes and two panel assays to identify the target serogroups: panel 1 detects O26, O111, and O121, and panel 2 detects O45, O103, O145. For E. coli O157:H7, the BAX System real-time PCR assay for this specific serotype was used. Sensitivity of each assay for the PCR targets was ≥1.23 × 103 CFU/ml in pure culture. Each assay was 100% inclusive for the strains tested (20 to 50 per assay), and no cross-reactivity with closely related strains was observed in any of the assays. The performance of the BAX System methods was compared with that of the FSIS Microbiology Laboratory Guidebook (MLG) methods for detection of the top six STEC and E. coli O157:H7 strains in ground beef and beef trim. Generally, results of the BAX System method were similar to those of the MLG methods for detecting non-O157 STEC and E. coli O157:H7. Reducing or eliminating novobiocin in modified tryptic soy broth (mTSB) may improve the detection of STEC O111 strains; one beef trim sample inoculated with STEC O111 produced a negative result when enriched in mTSB with 8 mg/liter novobiocin but was positive when enriched in mTSB without novobiocin. The results of this study indicate the feasibility of deploying a panel of real-time PCR assay configurations for the detection and monitoring of the top six STEC and E. coli O157:H7 strains in beef. The approach could easily be adapted for additional multiplex assays should regulations expand to include other O serogroups or virulence genes.


2001 ◽  
Vol 84 (3) ◽  
pp. 719-736 ◽  
Author(s):  
Charles B Bird ◽  
Rebecca J Hoerner ◽  
Lawrence Restaino ◽  
G Anderson ◽  
W Birbari ◽  
...  

Abstract Five different food types were analyzed by the Reveal for E. coli O157:H7 8-Hour Test System (Reveal 8) and either the U.S. Food and Drug Administration's Bacteriological Analytical Manual (BAM) culture method or the U.S. Department of Agriculture Food Safety Inspection Service (FSIS) culture method for the presence of E. coli O157:H7. A total of 27 laboratories representing academia and private industry in the United States and Canada participated. Food types were inoculated with E. coli O157:H7 at 2 different levels: a high level where predominantly positive results were expected, and a low level where fractional recovery was anticipated. During this study, 1110 samples and controls were analyzed by both the Reveal 8 and by BAM or FSIS by each of the collaborators (2220 samples in total). For each set of samples, 740 were artificially inoculated with E. coli O157:H7, and 370 were uninoculated controls. The Reveal 8 detected 528 presumptive positives of which 487 were confirmed positive by the BAM culture method. In comparison, BAM and FSIS detected 489 of the 740 artificially contaminated samples as positive. In an additional in-house study performed only on chilled and frozen raw ground beef, 240 artificially inoculated samples were analyzed by both the Reveal 8 and by FSIS. The Reveal 8 detected and confirmed 104 samples as positive compared to 79 confirmed positive by FSIS.


2014 ◽  
Vol 62 (3) ◽  
pp. 304-316 ◽  
Author(s):  
Orsolya Erdősi ◽  
Katalin Szakmár ◽  
Olivér Reichart ◽  
Zsuzsanna Szili ◽  
Noémi László ◽  
...  

The incidence of outbreaks of foodborne listeriosis has indicated the need for a reliable and rapid detection of the microbe in different foodstuffs. A method combining redox potential measurement and real-time polymerase chain reaction (PCR) was developed to detectListeria monocytogenesin artificially contaminated raw milk and soft cheese. Food samples of 25 g or 25 ml were homogenised in 225 ml of Listeria Enrichment Broth (LEB) with Oxford supplement, and the redox potential measurement technique was applied. ForListeriaspecies the measuring time was maximum 34 h. The absence ofL. monocytogenescould reliably be proven by the redox potential measurement method, butListeria innocuaandBacillus subtiliscould not be differentiated fromL. monocytogeneson the basis of the redox curves. The presence ofL. monocytogeneshad to be confirmed by real-time PCR. The combination of these two methods proved to detect < 10 cfu/g ofL. monocytogenesin a cost- and time-effective manner. This method can potentially be used as an alternative to the standard nutrient method for the rapid detection ofL. monocytogenesin food.


Author(s):  
Thomas Lonczynski ◽  
Laura Cowin

Abstract Background The Simultaneous Multiplex Real Time PCR (SIMUL-qPCR) Listeria species and monocytogenes Assay is a quick, reliable method for detecting Listeria species and monocytogenes in environmental and food samples. The assay multiplexes several targets in one run to properly identify Listeria species and monocytogenes. The assay uses proprietary media, Listeria Recovery and Enrichment Broth (LREB), for enrichment purposes. LREB was specifically formulated to improve the recovery and growth of Listeria while inhibiting competing background flora. Objective This report details the method validation study to validate frankfurters, ready-to-eat sliced turkey, soft fresh raw cheese, chicken salad, ice cream, cooked eggs, pasteurized milk, and frozen/cooked shrimp, as well as environmental surface sponges and swabs for stainless steel, plastic, rubber, ceramic tile, and sealed concrete. Methods Matrix studies, inclusivity/exclusivity, product consistency/stability, and robustness testing were conducted to assess the method’s performance. Results There were no statistically significant differences found between the candidate and reference methods in the matrix studies. Inclusivity/exclusivity testing showed that the assay was able to detect both Listeria species and monocytogenes strains while excluding the non-Listeria isolates. Small variations in critical test parameters (enrichment time, extraction reagent volume and extracted sample volume) did not adversely affect the assay’s performance, and stability testing indicated consistent results for at least one year. Conclusions The data presented in this report show that this a reliable method for detecting Listeria species and monocytogenes. Highlights This assay allows for one sample to be tested for both Listeria species and monocytogenes with one PCR test.


2007 ◽  
Vol 70 (11) ◽  
pp. 2596-2601 ◽  
Author(s):  
R. I. MORENO-ENRIQUEZ ◽  
A. GARCIA-GALAZ ◽  
E. ACEDO-FELIX ◽  
H. GONZALEZ-RIOS ◽  
J. E. CALL ◽  
...  

In the first part of this study, samples were collected from farms, cheese processing plants (CPPs), and retail markets located in various geographical areas of Sonora, Mexico, over a 12-month period during the summer of 2004 and winter of 2005. Four (all Queso Fresco [QF] from retail markets) of 349 total samples tested positive for Listeria monocytogenes (Lm). Of these four positive samples, three were collected in the northern region and one in the southern region of Sonora. Additionally, two were collected during the winter months, and two were collected during the summer months. For the second part of the study, a total of 39 samples from a farm, a CPP, and retail markets were collected and processed according to a combination of the Norma Oficial Mexicana NOM-143-SSA1-1995.10 method (NOM) and the U.S. Food and Drug Administration (FDA) Bacteriological Analytical Manual method, and 27 samples from these same locations were collected and processed according to the U.S. Department of Agriculture Food Safety and Inspection Service method (USDA-FSIS). The NOM-FDA method recovered the pathogen from 6 (15%) of 39 samples (one cheese and five product contact surfaces), while the USDA-FSIS method recovered the pathogen from 5 (18.5%) of 27 samples (all product contact surfaces). In addition, the 40 isolates recovered from the 15 total samples that tested positive for Lm grouped into five distinct pulsotypes that were ca. 60% related, as determined by pulsed-field gel electrophoresis analysis. The results of this study confirmed a 3.4% prevalence of Lm in QF collected from retail markets located in Sonora and no appreciable difference in the effectiveness of either the NOM-FDA or USDA-FSIS method to recover the pathogen from cheese or environmental samples.


2016 ◽  
Vol 99 (1) ◽  
pp. 112-123
Author(s):  
Oscar Caballero ◽  
Susan Alles ◽  
Quynh-Nhi Le ◽  
R Lucas Gray ◽  
Edan Hosking ◽  
...  

Abstract Work was conducted to validate performance of the ANSR® for Listeria monocytogenes method in selected food and environmental matrixes. This DNA-based assay involves amplification of nucleic acid via an isothermal reaction based on nicking enzyme amplification technology. Following single-step sample enrichment for 16–24 h for most matrixes, the assay is completed in 40 min using only simple instrumentation. When 50 distinct strains of L. monocytogenes were tested for inclusivity, 48 produced positive results, the exceptions being two strains confirmed by PCR to lack the assay target gene. Forty-seven nontarget strains (30 species), including multiple non-monocytogenes Listeria species as well as non-Listeria, Gram-positive bacteria, were tested, and all generated negative ANSR assay results. Performance of the ANSR method was compared with that of the U.S. Department of Agriculture, Food Safety and Inspection Service Microbiology Laboratory Guidebook reference culture procedure for detection of L. monocytogenes in hot dogs, pasteurized liquid egg, and sponge samples taken from an inoculated stainless steel surface. In addition, ANSR performance was measured against the U.S. Food and Drug Administration Bacteriological Analytical Manual reference method for detection of L. monocytogenes in Mexican-style cheese, cantaloupe, sprout irrigation water, and guacamole. With the single exception of pasteurized liquid egg at 16 h, ANSR method performance as quantified by the number of positives obtained was not statistically different from that of the reference methods. Robustness trials demonstrated that deliberate introduction of small deviations to the normal assay parameters did not affect ANSR method performance. Results of accelerated stability testing conducted using two manufactured lots of reagents predicts stability at the specified storage temperature of 4°C of more than 1 year.


1992 ◽  
Vol 55 (12) ◽  
pp. 952-959 ◽  
Author(s):  
PEGGY S. HAYES ◽  
LEWIS M. GRAVES ◽  
B. SWAMINATHAN ◽  
GLORIA W. AJELLO ◽  
GEORGIA B. MALCOLM ◽  
...  

Three selective enrichment procedures—the U.S. Food and Drug Administration (FDA) method, the U.S. Department of Agriculture (USDA) method, and the Netherlands Government Food Inspection Service (NGFIS) method—were compared for isolating Listeria monocytogenes from contaminated foods. The foods were obtained from the refrigerators of patients with culture-proven listeriosis who were identified through multistate active surveillance in a U.S. population of 19 million. The study was designed to identify foods that may be important in transmission of L. monocytogenes in sporadic cases of human listeriosis. Of 899 foods analyzed by all three methods, 121 were positive for L. monocytogenes by at least one method. The three enrichment methods detected L. monocytogenes in 65% (FDA), 74% (USDA), and 74% (NGFIS) of the foods shown to contain L. monocytogenes. The differences among the three methods were not statistically significant. However, the recovery of L. monocytogenes by a combination of any two methods (USDA-FDA 88%, USDA-NGFIS 91%, FDA-NGFIS 87%) was significantly better than that by one method alone (p &lt; 0.02). The differences among the combinations of methods were not statistically significant. These results suggest that at least two enrichment methods must be used in combination to recover L. monocytogenes from contaminated foods with a success rate near 90%. Correlations were observed between negative results and low (&lt;0.3 CFU/g) level of L. monocytogenes contamination for the USDA (p &lt;&lt; 0.001) and NGFIS (p &lt;&lt; 0.001) methods. A similar but somewhat weaker association was observed for the FDA method (p &lt; 0.06).


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