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Martins WF, Severo DDS, Longhi DA, de Aragão GMF. Comparison of SYBR® Green qPCR assay and plate count method to describe growth of Weissella viridescens and Leuconostoc mesenteroides in pure and mixed cultivation. Food Microbiol 2024; 119:104452. [PMID: 38225053 DOI: 10.1016/j.fm.2023.104452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 11/28/2023] [Accepted: 12/18/2023] [Indexed: 01/17/2024]
Abstract
The current study was conducted to statistically compare the SYBR® Green quantitative polymerase chain reaction (qPCR) assay and the conventional plate counting (PC) method to construct growth curves of a cocktail of Weissella viridescens in pure culture under different isothermal storage conditions (4, 8, 14, and 30 °C) and in mixed culture with Leuconostoc mesenteroides at 8 °C. The efficiency and specificity of the qPCR standard curves were confirmed, and both methods were adequate to quantify the growth kinetics of W. viridescens at all isothermal temperatures, demonstrating a good correlation and agreement. The efficiencies of the standard curves varied between 98% and 102%. The SYBR® Green qPCR assay was also able to differentiate the growth curves of W. viridescens and L. mesenteroides in the mixed culture at 8 °C. Additionally, the SYBR® Green qPCR method was considered a faster and more sensitive alternative to construct growth curves under different isothermal conditions and differentiate morphologically similar lactic acid bacteria. Overall, the results suggest that the SYBR® Green qPCR method is a reliable and efficient tool to study microbial growth kinetics in pure and mixed cultures.
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Affiliation(s)
- Wiaslan Figueiredo Martins
- Department of Food Technology, Goiano Federal Institute of Education, Science, and Technology, IF Goiano/Morrinhos Campus, Zip Code 75650-000, Morrinhos, GO, Brazil; Chemical and Food Engineering Department, Federal University of Santa Catarina, EQA/UFSC, Zip Code 88040-900, Florianopolis, SC, Brazil.
| | - Danielle de Sousa Severo
- Chemical and Food Engineering Department, Federal University of Santa Catarina, EQA/UFSC, Zip Code 88040-900, Florianopolis, SC, Brazil
| | - Daniel Angelo Longhi
- LaBeM - Laboratory of Bioactives and Microbiology, School of Food Engineering, Federal University of Paraná, UFPR/Jandaia do Sul Campus, Zip Code 86900-000, Jandaia do Sul, PR, Brazil
| | - Gláucia Maria Falcão de Aragão
- Chemical and Food Engineering Department, Federal University of Santa Catarina, EQA/UFSC, Zip Code 88040-900, Florianopolis, SC, Brazil
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Dorn-In S, Daldrup E, Mang S, Esteban-Cuesta I, Gareis M, Schwaiger K. Viable Campylobacter jejuni on Eggshells and Its Potential to Cross-contaminate Egg White and Yolk When Using a Manual Separation Technique, Determined by Culture and Propidium Monoazide (PMA) qPCR. J Food Prot 2024; 87:100246. [PMID: 38369191 DOI: 10.1016/j.jfp.2024.100246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Revised: 01/07/2024] [Accepted: 02/13/2024] [Indexed: 02/20/2024]
Abstract
Manual separation of egg yolk from egg white using the eggshell is common practice in private households. For this, the egg is cracked and both components are separated by passing the egg yolk back and forth between the two halves of the eggshell, allowing the egg white to drip down while the egg yolk remains in the shell. During this process, the egg content naturally gets in contact with the outside of the eggshell, which might lead to a cross-contamination with its microorganisms, thus was correspondingly assessed in this study. Campylobacter jejuni is one of the most important zoonotic pathogens that can be found on eggshells. Therefore, this bacterium was used to artificially contaminate the eggshells (n = 22) with concentrations of 3.1 ± 0.6 log10 cfu/g. After separating the egg yolk from the egg white, cross-contamination was determined using culture and qPCR. Altogether, cross-contaminations with C. jejuni were found in 15 egg white (68%) and in three egg yolk (14%) samples. Afterward, 90 eggs from 30 egg packs from different producers in and around Munich (Germany) were obtained for field study purposes. To address the problem of culturing due to a possible viable but nonculturable (VBNC) status of C. jejuni, a method to differentiate viable and dead C. jejuni on eggshell using 10 µM propidium monoazide (PMA) and qPCR was developed. As a result, seven egg packs (23%) were positive for C. jejuni. Of these, only one (3%) was contaminated with viable cells, but still in a concentration of 3.3 log10 cells/g shell. According to these results and considering that eggshells might also be naturally contaminated with other pathogens, the authors recommend avoiding the manual separation technique of egg white and yolk by the eggshell. Especially if raw egg white or yolk is used for preparation of not sufficiently heated foods, where contaminating pathogens are not inactivated during processing, this technique might be a safety hazard for the consumer.
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Affiliation(s)
- Samart Dorn-In
- Unit of Food Hygiene and Technology, Institute of Food Safety, Food Technology and Veterinary Public Health, University of Veterinary Medicine Vienna, Veterinaerplatz 1, 1210 Vienna, Austria.
| | - Eva Daldrup
- Chair of Food Safety and Analytics, Faculty of Veterinary Medicine, Ludwig Maximilian University of Munich, Schoenleutnerstr. 8, 85764 Oberschleissheim, Germany
| | - Sirkka Mang
- Chair of Food Safety and Analytics, Faculty of Veterinary Medicine, Ludwig Maximilian University of Munich, Schoenleutnerstr. 8, 85764 Oberschleissheim, Germany
| | - Irene Esteban-Cuesta
- Chair of Food Safety and Analytics, Faculty of Veterinary Medicine, Ludwig Maximilian University of Munich, Schoenleutnerstr. 8, 85764 Oberschleissheim, Germany
| | - Manfred Gareis
- Chair of Food Safety and Analytics, Faculty of Veterinary Medicine, Ludwig Maximilian University of Munich, Schoenleutnerstr. 8, 85764 Oberschleissheim, Germany
| | - Karin Schwaiger
- Unit of Food Hygiene and Technology, Institute of Food Safety, Food Technology and Veterinary Public Health, University of Veterinary Medicine Vienna, Veterinaerplatz 1, 1210 Vienna, Austria
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Reichelt B, Szott V, Stingl K, Roesler U, Friese A. Detection of Viable but Non-Culturable (VBNC)- Campylobacter in the Environment of Broiler Farms: Innovative Insights Delivered by Propidium Monoazide (PMA)-v-qPCR Analysis. Microorganisms 2023; 11:2492. [PMID: 37894150 PMCID: PMC10609165 DOI: 10.3390/microorganisms11102492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Revised: 09/30/2023] [Accepted: 10/03/2023] [Indexed: 10/29/2023] Open
Abstract
Campylobacteriosis cases in humans are of global concern, with high prevalence rates in the poultry reservoir considered the most important source of infection. Research findings show Campylobacters' ability to enter a viable but non-culturable (VBNC) state, remaining "viable" but unable to grow on culture media. We explored the persistence of VBNC states in specific environments, particularly at broiler farms, as this state may lead to an underestimation of the present Campylobacter prevalence. For VBNC detection, a propidium monoazide PMA-dye viability qPCR (v-qPCR) was used in combination with cultivation methods. We examined samples collected from broiler farm barns and their surroundings, as well as chicken manure from experimental pens. In addition, the tenacity of culturable and VBNC-Campylobacter was studied in vitro in soil and water. In a total of three visits, Campylobacter was not detected either culturally or by v-qPCR (no Campylobacter DNA) in the environment of the broiler farms. In four visits, however, VBNC-Campylobacter were detected both inside and outside the barns. The overall prevalence in environmental samples was 15.9% for VBNC-Campylobacter, 62.2% for Campylobacter DNA, and 1.2% for culturable C. jejuni. In the experimental pens, no cultivable C. jejuni was detected in chicken manure after 24 h. Strikingly, "VBNC-Campylobacter" persisted even after 72 h. "VBNC-Campylobacter" were confirmed in barn surroundings and naturally contaminated chicken manure. Laboratory studies revealed that VBNC-Campylobacter can remain intact in soil for up to 28 days and in water for at least 63 days, depending on environmental conditions.
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Affiliation(s)
- Benjamin Reichelt
- Institute for Animal Hygiene and Environmental Health, Freie Universität Berlin, 14163 Berlin, Germany; (B.R.)
| | - Vanessa Szott
- Institute of Food Safety and Food Hygiene, Freie Universität Berlin, 14163 Berlin, Germany;
| | - Kerstin Stingl
- Department of Biological Safety, German Federal Institute for Risk Assessment (BfR), 10589 Berlin, Germany
| | - Uwe Roesler
- Institute for Animal Hygiene and Environmental Health, Freie Universität Berlin, 14163 Berlin, Germany; (B.R.)
| | - Anika Friese
- Institute for Animal Hygiene and Environmental Health, Freie Universität Berlin, 14163 Berlin, Germany; (B.R.)
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Al-baqir A, Hassanin O, Al-Rasheed M, Ahmed MS, Mohamed MHA, El Sayed MS, Megahed M, El-Demerdash A, Hashem Y, Eid A. Mycoplasmosis in Poultry: An Evaluation of Diagnostic Schemes and Molecular Analysis of Egyptian Mycoplasma gallisepticum Strains. Pathogens 2023; 12:1131. [PMID: 37764939 PMCID: PMC10536284 DOI: 10.3390/pathogens12091131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2023] [Revised: 08/31/2023] [Accepted: 09/02/2023] [Indexed: 09/29/2023] Open
Abstract
Infections with Mycoplasma gallisepticum (MG) in poultry are associated with a wide range of disease conditions, including those affecting the respiratory and reproductive systems. The purpose of this study was to endorse the more sensitive diagnostic scheme for MG infection and identify the best molecular marker for MG phylogenetic analysis using six housekeeping genes: mgc2, mraW, atpG, ugpA, DUF31196, and lgT. For these purposes, 55 poultry flocks of different species were screened using either qRT-PCR or PCR techniques analogous to conventional culturing from non-cultured and cultured swabs on PPLO broth. The rate of MG positivity was the highest when using qRT-PCR from cultured broth (89.0%) and the lowest when using conventional culturing (34.5%). Compared to qRT-PCR from broth, statistical analysis using the Roc curve in MedCalc statistical software showed that the PCR schemes (qRT-PCR from swabs and PCR from swabs and broth) performed better than conventional culturing in terms of sensitivity, accuracy, and area under the curve (AUC), suggesting that they may be more reliable schemes. Further support was added by Cohen's kappa test, showing moderate agreement between the molecular approaches. Among the six screened genes, mgc2 and mraW had the highest detection rates (69% and 65.4%, respectively). The comparative phylogenetic analysis revealed that mgc2 or atpG gene sequences distinguished MG isolates into different clades with high discriminatory power.
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Affiliation(s)
- Ahmed Al-baqir
- Avian and Rabbit Medicine Department, Faculty of Veterinary Medicine, Zagazig University, Zagazig 44511, Sharkia, Egypt; (A.A.-b.)
| | - Ola Hassanin
- Avian and Rabbit Medicine Department, Faculty of Veterinary Medicine, Zagazig University, Zagazig 44511, Sharkia, Egypt; (A.A.-b.)
| | - Mohammed Al-Rasheed
- Department of Clinical Sciences, College of Veterinary Medicine, King Faisal University, P.O. Box 400, Al-Ahsa 31982, Saudi Arabia (M.S.A.); (M.H.A.M.)
- Avian Research Center, King Faisal University, P.O. Box 400, Al-Ahsa 31982, Saudi Arabia;
| | - Mohamed S. Ahmed
- Department of Clinical Sciences, College of Veterinary Medicine, King Faisal University, P.O. Box 400, Al-Ahsa 31982, Saudi Arabia (M.S.A.); (M.H.A.M.)
- Avian Research Center, King Faisal University, P.O. Box 400, Al-Ahsa 31982, Saudi Arabia;
- Department of Poultry Diseases, Faculty of Veterinary Medicine, South Valley University, Qena 83523, Egypt
| | - Mahmoud H. A. Mohamed
- Department of Clinical Sciences, College of Veterinary Medicine, King Faisal University, P.O. Box 400, Al-Ahsa 31982, Saudi Arabia (M.S.A.); (M.H.A.M.)
- Avian Research Center, King Faisal University, P.O. Box 400, Al-Ahsa 31982, Saudi Arabia;
| | - Mohamed Shawky El Sayed
- Avian Research Center, King Faisal University, P.O. Box 400, Al-Ahsa 31982, Saudi Arabia;
- Veterinary Serum and Vaccine Research Institute, Abassia, Cairo 11381, Egypt
| | - Mohamed Megahed
- Avian and Rabbit Medicine Department, Faculty of Veterinary Medicine, Zagazig University, Zagazig 44511, Sharkia, Egypt; (A.A.-b.)
| | - Azza El-Demerdash
- Laboratory of Biotechnology, Department of Microbiology, Agriculture Research Centre (ARC), Animal Health Research Institute (AHRI), Zagazig 44516, Egypt;
| | - Youserya Hashem
- Mycoplasma Department, Animal Health Research Institute, Agricultural Research Center, Dokki, Giza 12618, Egypt;
| | - Amal Eid
- Avian and Rabbit Medicine Department, Faculty of Veterinary Medicine, Zagazig University, Zagazig 44511, Sharkia, Egypt; (A.A.-b.)
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Chen Y, Hu Y, Lu X. An Integrated Paper Microfluidic Device Based on Isothermal Amplification for Simple Sample-to-Answer Detection of Campylobacter jejuni. Appl Environ Microbiol 2023; 89:e0069523. [PMID: 37382522 PMCID: PMC10370333 DOI: 10.1128/aem.00695-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Accepted: 06/03/2023] [Indexed: 06/30/2023] Open
Abstract
Campylobacter jejuni is recognized as the most common species in the genus Campylobacter that causes foodborne diseases. The main reservoirs harboring C. jejuni are poultry products, which are associated with most illnesses, creating a demand for effective detection methods to achieve point-of-need diagnostics. We developed an easy-to-use, hybrid paper/polymer-based microfluidic device that integrates paper-based DNA extraction, isothermal nucleic acid amplification, and lateral flow detection. Overall, the recombinase polymerase amplification (RPA) reaction was completed in 20 min and demonstrated 100% specificity to C. jejuni, including 2 reference strains and 6 wild strains isolated from the agroecosystem, 9 other Campylobacter subspecies strains, and 11 non-Campylobacter strains. The limit of detection (LOD) was 46 CFU/mL with DNA extracted on the cellulose paper. The sensitivity was reduced to 460 CFU/mL on the integrated hybrid paper/polymer-based microfluidic device. This device could detect C. jejuni spiked at concentrations ranging from 101 to 102 CFU/g in chicken meat after an enrichment of 5 to 10 h. For C. jejuni levels of >102 CFU/g, it managed to confirm positive results immediately, without bacterial enrichment. RPA reagents and primers remained stable on the paper platform at 22°C for 12 h. After lyophilization and storage on paper, the RPA reaction showed consistent sensitivity for 3 days, and the LOD was reduced to 103 CFU/mL when storage was extended to 25 days. The use of this hybrid paper/polymer-based microfluidic device enabled detection of Campylobacter in foods with high specificity and sensitivity, demonstrating its potential as a reliable point-of-need diagnostic platform for on-site conditions due to its low cost, portability, and simplicity. IMPORTANCE The global health and economic burden of Campylobacter prompts the development of novel detection techniques that can be implemented in resource-limited and on-site settings. This study described point-of-need identification of C. jejuni using a hybrid paper/polymer-based microfluidic device that is easy to operate. This device had high specificity and sensitivity toward C. jejuni and significantly reduced the total analysis time compared to conventional culture-based methods. Nucleic acid extraction was simplified from intensive pipetting to a paper dipstick, making it more convenient for use in the field as a promising tool for future routine surveillance and outbreak investigation.
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Affiliation(s)
- Yunxuan Chen
- Food, Nutrition and Health Program, Faculty of Land and Food Systems, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Yaxi Hu
- Food, Nutrition and Health Program, Faculty of Land and Food Systems, The University of British Columbia, Vancouver, British Columbia, Canada
- Food Science Program, Department of Chemistry, Carleton University, Ottawa, Ontario, Canada
| | - Xiaonan Lu
- Food, Nutrition and Health Program, Faculty of Land and Food Systems, The University of British Columbia, Vancouver, British Columbia, Canada
- Department of Food Science and Agricultural Chemistry, McGill University Macdonald Campus, Quebec, Canada
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6
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Sun A, Mirzayans PM, Piggott AM, Stanton JAL, Sunna A. Adapted method for rapid detection and quantification of pathogen Campylobacter jejuni from environmental water samples. FEMS Microbiol Ecol 2023; 99:fiad058. [PMID: 37245057 DOI: 10.1093/femsec/fiad058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 04/23/2023] [Accepted: 05/26/2023] [Indexed: 05/29/2023] Open
Abstract
Building on a previously developed workflow for rapid and sensitive pathogen detection by qPCR, this work has established a sample treatment strategy that produces consistent quantification efficiencies (QEs) for Campylobacter jejuni against a complex and highly variable sample matrix from a suburban river. The individual treatments most effective at minimizing the inhibitory effects of the sample matrix were pH buffering with HEPES (50 mM, pH 5.7) and addition of the surfactant Tween 20 (2% v/v). Unexpectedly, sample acidification (pH 4-5) resulting from the use of aged Tween 20 that had undergone partial hydrolysis, appeared to play a key role in enhancing QE. This effect could be replicated by direct pH adjustment with dilute hydrochloric acid and may be linked to the solubilization and removal of inhibitory particles at an acidic pH. While the effectiveness of each individual treatment method varied, a combined treatment of either HEPES buffer + Tween 20, or direct pH adjustment + Tween 20, consistently produced QEs of 60%-70% and up to 100%, respectively, over a sampling period of one year. The consistency and scalability of this workflow make it a suitable alternative to culture-based ISO methods for detecting Campylobacter spp.
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Affiliation(s)
- Angela Sun
- School of Natural Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - Paul M Mirzayans
- School of Natural Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - Andrew M Piggott
- School of Natural Sciences, Macquarie University, Sydney, NSW 2109, Australia
- Biomolecular Discovery Research Centre, Macquarie University, Sydney, NSW 2109, Australia
| | - Jo-Ann L Stanton
- Department of Anatomy, School of Biomedical Sciences, University of Otago, PO Box 56, Dunedin 9054, New Zealand
| | - Anwar Sunna
- School of Natural Sciences, Macquarie University, Sydney, NSW 2109, Australia
- Biomolecular Discovery Research Centre, Macquarie University, Sydney, NSW 2109, Australia
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Ferrari S, Ástvaldsson Á, Jernberg T, Stingl K, Messelhäußer U, Skarin H. Validation of PCR methods for confirmation and species identification of thermotolerant Campylobacter as part of EN ISO 10272 - Microbiology of the food chain - Horizontal method for detection and enumeration of Campylobacter spp. Int J Food Microbiol 2023; 388:110064. [PMID: 36610236 DOI: 10.1016/j.ijfoodmicro.2022.110064] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 12/21/2022] [Accepted: 12/22/2022] [Indexed: 12/29/2022]
Abstract
This article describes the outline and organisation of the validation of three multiplex PCR methods for species identification and/or confirmation of thermotolerant Campylobacter spp. The three PCR methods were validated against the reference method described in the EN ISO standard 10272:2017. The results of the PCR methods were compared against the reference method in a method comparison study and an interlaboratory study based on EN ISO 16140-6:2019. The performance, in terms of inclusivity and exclusivity, of each of the eight PCR targets were comparable to the performance of the reference method: close, equal, or better depending on the target. In total, all three PCR methods were concluded to be equally qualified as the reference method for molecular identification and/or confirmation of thermotolerant Campylobacter spp., C. jejuni, C. coli and C. lari isolated from the food chain and have been included in Amendment 1 of ISO 10272:2017.
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Affiliation(s)
| | | | | | - Kerstin Stingl
- German Federal Institute for Risk Assessment, Department of Biological Safety, National Reference Laboratory for Campylobacter, 12277 Berlin, Germany
| | - Ute Messelhäußer
- Bavarian Health and Food Safety Authority, 91058 Erlangen, Bavaria, Germany
| | - Hanna Skarin
- National Veterinary Institute, 751 89 Uppsala, Sweden.
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Lanzl M, Zwietering M, Abee T, den Besten H. Combining enrichment with multiplex real-time PCR leads to faster detection and identification of Campylobacter spp. in food compared to ISO 10272–1:2017. Food Microbiol 2022; 108:104117. [DOI: 10.1016/j.fm.2022.104117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 07/26/2022] [Accepted: 08/14/2022] [Indexed: 11/16/2022]
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Yang L, Long Y, Li Q, Song W, Huang Y, Liang G, Yu D, Zhou M, Xu G, Chen Y, Huang C, Tang X. Detection of suid herpesvirus 1 infectivity in pigs by propidium monoazide-qPCR. Front Vet Sci 2022; 9:975726. [DOI: 10.3389/fvets.2022.975726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Accepted: 10/05/2022] [Indexed: 11/13/2022] Open
Abstract
At present, there is no effective experimental method for detecting whether the suid herpesvirus 1 (SHV-1) detected in pigs is infectious. Although the technique of quantitative polymerase chain reaction (qPCR) has significantly improved the detection rate and accuracy of the disease, it does not differentiate between infective and non-infective status of the virus. Propidium monoazide (PMA) is a dye that can be combined with DNA molecules. The decomposition of PMA produces an azene compound covalently crosslinked with DNA molecules, thereby inhibiting PCR amplification of DNA. In this study, the combination of PMA and qPCR was used to determine the infectivity of SHV-1. We optimized the method from the selection of primers, the working concentration of PMA, and the method of inactivation using UV or heat inactivation. We found that when specific primer 1 was used and a PMA working concentration was 50–100 μM, heat inactivation was able to distinguish whether SHV-1 was infectious or not. We also showed that UV prevented the virus from replicating, it did not destroy the capsid of the virus, and therefore, PMA cannot enter the virus and bind to the nucleic acid of the virus. Consequently, there is no way to identify the infectivity of the virus using UV inactivation. The study showed that the method was stable and the detection rate reached 96%. In conclusion, this method exhibited strong specificity and high sensitivity and can identify the infectivity of SHV-1. This method has practical significance for clinical virus isolation and the effects of disinfection of farms.
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Chicken Skin Decontamination of Thermotolerant Campylobacter spp. and Hygiene Indicator Escherichia coli Assessed by Viability Real-Time PCR. Pathogens 2022; 11:pathogens11060706. [PMID: 35745559 PMCID: PMC9230925 DOI: 10.3390/pathogens11060706] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 05/31/2022] [Accepted: 06/10/2022] [Indexed: 11/17/2022] Open
Abstract
Thermotolerant Campylobacter spp. are fecal contaminants of chicken meat with serious implications for human health. E. coli is considered as hygiene indicator since, in contrast to Campylobacter. spp., the bacterium is generally present in the avian gut. Stress exposure may transiently cease bacterial division. Therefore, colony forming units (CFU) may underestimate the infection risk of pathogens. We developed a viability real-time PCR (v-qPCR) for the quantification of viable E. coli targeting the uidA gene, encoding β-glucuronidase, which is usually detected for phenotypic species identification. The short- and long-term effects of decontaminating chicken skin on the survival of both C. jejuni and an ESBL-producing E. coli were evaluated by CFU and v-qPCR. The results showed that freezing and storage in cool conditions are potentially underestimated by CFU but not by v-qPCR. The effect of treatment with peroxyacetic acid on survival was consistently detected by CFU and v-qPCR. v-qPCR analysis detected bacterial survival upon the application of lactic acid, which awaits further analysis. Interestingly, both bacteria showed similar kinetics of inactivation upon the application of reduction strategies, suggesting that E. coli might be a complementary hygiene indicator. We conclude that v-qPCR can improve food safety under the consideration of some limitations.
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Digital Droplet-PCR for Quantification of Viable Campylobacter jejuni and Campylobacter coli in Chicken Meat Rinses. APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12115315] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The EU commission established Regulation (2017/1495) in 2017 to reduce Campylobacter on chicken skin and to decrease the number of human cases of campylobacteriosis attributable to the consumption of poultry meat. A Process Hygiene Criterion based on colony-forming unit data was set to a maximum of 1000 CFU Campylobacter spp. per gram chicken neck skin at slaughterhouses. Confronted with stressors, including cold, oxidative stress or antibiotic treatment, live cells may enter into a viable but non-cultivable state (VBNC) and lose the ability to grow, in reference to the plate count ISO 10272-2:2017 method, but still possess the potential to recover and cause infections under favorable conditions. In this study, a droplet digital PCR combined with the intercalating dye propidium monoazide (PMA) was established for quantification of C. coli and C. jejuni in chicken meat rinses. The PMA was used to inactivate DNA from dead cells in this technique. This method was successfully validated against the reference method according to ISO 16140-2:2016 for accuracy and relative trueness. Additionally, it presented a 100% selectivity for Campylobacter jejuni and C. coli. Moreover, the technical measurement uncertainty was determined according to ISO 19036:2019, and the applicability of ddPCR for quantifying C. coli and C. jejuni in chicken meat rinses was investigated on naturally contaminated samples from slaughterhouses and supermarkets. Results obtained from this study demonstrated a strong correlation to qPCR as well as the classical microbiological reference method.
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12
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Chen L, Li L, Xie X, Chai A, Shi Y, Fan T, Xie J, Li B. An Improved Method for Quantification of Viable Fusarium Cells in Infected Soil Products by Propidium Monoazide Coupled with Real-Time PCR. Microorganisms 2022; 10:microorganisms10051037. [PMID: 35630479 PMCID: PMC9143521 DOI: 10.3390/microorganisms10051037] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 05/07/2022] [Accepted: 05/08/2022] [Indexed: 11/30/2022] Open
Abstract
Fusarium is a soil-borne pathogen that causes root rot disease in cucumber. To date, quantitative real-time PCR (qPCR) is a common tool to detect the content of Fusarium in soil. However, qPCR cannot distinguish between viable and nonviable cells. The aim of this study was to develop a detection technique to pretreat tissue fluid with propidium monoazide (PMA) followed by extract DNA, and then to quantify viable Fusarium cells in contaminated soil. In this work, the specific primer pair F8-1/F8-2 was designed based on the translation elongation factor (EF) gene and a PMA-qPCR assay was established to amplify and quantify soils of viable Fusarium cells. The PMA pretreatment test was optimized, which indicated that the optimal PMA concentration and light exposure time were 50 mmol L−1 and 15 min, respectively. The lowest limit of viable cells in suspension detected and soil by PMA-qPCR were 82 spore mL−1 and 91.24 spore g−1, respectively. For naturally contaminated soil, viable Fusarium cells were detected in eight of the 18 samples, and the Fusarium amount ranged from 104 to 106 spore g−1. In conclusion, the PMA-qPCR method has the characteristics of high sensitivity, efficiency, and time saving, which could support nursery plants to avoid Fusarium infection and agro-industry losses.
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Affiliation(s)
- Lida Chen
- College of Horticulture, Gansu Agricultural University, Lanzhou 730070, China;
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing 100081, China; (L.L.); (X.X.); (A.C.); (Y.S.); (T.F.)
| | - Lei Li
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing 100081, China; (L.L.); (X.X.); (A.C.); (Y.S.); (T.F.)
| | - Xuewen Xie
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing 100081, China; (L.L.); (X.X.); (A.C.); (Y.S.); (T.F.)
- Shouguang R&D Center of Vegetables, Chinese Academy of Agricultural Sciences, Weifang 262700, China
| | - Ali Chai
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing 100081, China; (L.L.); (X.X.); (A.C.); (Y.S.); (T.F.)
| | - Yanxia Shi
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing 100081, China; (L.L.); (X.X.); (A.C.); (Y.S.); (T.F.)
| | - Tengfei Fan
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing 100081, China; (L.L.); (X.X.); (A.C.); (Y.S.); (T.F.)
| | - Jianming Xie
- College of Horticulture, Gansu Agricultural University, Lanzhou 730070, China;
- Correspondence: (J.X.); (B.L.)
| | - Baoju Li
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing 100081, China; (L.L.); (X.X.); (A.C.); (Y.S.); (T.F.)
- Correspondence: (J.X.); (B.L.)
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13
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Okada A, Tsuchida M, Rahman MM, Inoshima Y. Two-Round Treatment With Propidium Monoazide Completely Inhibits the Detection of Dead Campylobacter spp. Cells by Quantitative PCR. Front Microbiol 2022; 13:801961. [PMID: 35547143 PMCID: PMC9082804 DOI: 10.3389/fmicb.2022.801961] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Accepted: 03/28/2022] [Indexed: 11/13/2022] Open
Abstract
Campylobacter spp. are known as important foodborne gastroenteric pathogens worldwide. Campylobacter spp. can exist in a viable but non-culturable (VBNC) state under unsuitable environmental conditions, which is undetectable by conventional culture methods. Quantitative polymerase chain reaction (qPCR) can be used to detect VBNC Campylobacter spp.; however, both viable and dead bacteria are detected during qPCR and are indistinguishable. Propidium monoazide (PMA), which can only enter dead bacterial cells through a damaged cell wall/cell membrane, binds to DNA and inhibits qPCR. PMA treatment has been performed along with qPCR (PMA-qPCR) to detect viable bacteria. However, the efficacy of detection inhibition differed among studies, and PMA can potentially enter living cells after changes in cell membrane permeability. In this study, we optimized the PMA treatment method by conducting it before qPCR. Two-round PMA treatment completely inhibited the qPCR signals from dead cells, whereas single-round PMA treatment failed to facilitate this. An optimized PMA-qPCR method was developed using commercial chicken meat, and VBNC Campylobacter spp., which are undetectable using conventional culture-based methods, were successfully detected. In conclusion, this study presents a novel, efficient PMA treatment method for the detection of viable Campylobacter spp., including VBNC Campylobacter spp., in chicken meat. We believe that this method will aid the reliable risk assessment of commercial chicken meat.
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Affiliation(s)
- Ayaka Okada
- Laboratory of Food and Environmental Hygiene, Faculty of Applied Biological Sciences, Cooperative Department of Veterinary Medicine, Gifu University, Gifu, Japan.,Education and Research Center for Food Animal Health, Gifu University (GeFAH), Gifu, Japan
| | - Mizuki Tsuchida
- Laboratory of Food and Environmental Hygiene, Faculty of Applied Biological Sciences, Cooperative Department of Veterinary Medicine, Gifu University, Gifu, Japan
| | - Md Matiur Rahman
- Laboratory of Food and Environmental Hygiene, Faculty of Applied Biological Sciences, Cooperative Department of Veterinary Medicine, Gifu University, Gifu, Japan.,The United Graduate School of Veterinary Sciences, Gifu University, Gifu, Japan.,Department of Medicine, Faculty of Veterinary, Animal and Biomedical Sciences, Sylhet Agricultural University, Sylhet, Bangladesh
| | - Yasuo Inoshima
- Laboratory of Food and Environmental Hygiene, Faculty of Applied Biological Sciences, Cooperative Department of Veterinary Medicine, Gifu University, Gifu, Japan.,Education and Research Center for Food Animal Health, Gifu University (GeFAH), Gifu, Japan.,The United Graduate School of Veterinary Sciences, Gifu University, Gifu, Japan.,Joint Graduate School of Veterinary Sciences, Gifu University, Gifu, Japan
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14
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Shi A, Li S, Ma H, Du XJ, Wang S, Lu X. Survival of Salmonella in Tea Under Different Storage Conditions and Brewing Methods. Front Microbiol 2022; 13:816667. [PMID: 35369509 PMCID: PMC8971837 DOI: 10.3389/fmicb.2022.816667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Accepted: 02/28/2022] [Indexed: 11/13/2022] Open
Abstract
Salmonella is one of the leading causes of bacterial gastroenteritis. High prevalence of Salmonella in environment is partially due to its ability to enter the “viable but non-culturable” (VBNC) state when they encounter unfavorable conditions. Dried teas are traditionally believed to have a low risk of causing salmonellosis. This study investigated the survival of Salmonella in four types of dried teas under different storage conditions and brewing methods. A method that coupled propidium monoazide (PMA) and quantitative PCR was optimized to quantify VBNC Salmonella cells to assess the risk of Salmonella contamination in teas after brewing. Each tea sample was inoculated with Salmonella at an 8 log CFU/ml concentration and stored at 4, 10, and 25°C. Under three storage conditions, the number of survived Salmonella was highest in teas stored at 4°C and lowest in teas stored at 25°C. After storage of 120 days, culturable Salmonella was detected from all samples ranging from 6–7 log CFU/g (4°C storage) to 3–4 log CFU/g (25°C storage). The effectiveness of brewing methods in inactivating Salmonella was assessed by brewing inoculated teas at room temperature, 55, 75, and 100°C for 10 min. Brewing teas at 75 and 100°C significantly (P < 0.05) reduced the number of viable Salmonella, but VBNC Salmonella formed when brewed at 75°C. Altogether, Salmonella can persist in dried teas for over 3 months at a temperature ranging from 4 to 25°C, and thermal treatment delivered during home brewing may not eradicate Salmonella in teas.
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Affiliation(s)
- Aiying Shi
- Key Laboratory of Food Nutrition and Safety, Ministry of Education of China, Tianjin University of Science and Technology, Tianjin, China
| | - Shenmiao Li
- Department of Food Science and Agricultural Chemistry, Faculty of Agricultural and Environmental Sciences, McGill University, Sainte-Anne-de-Bellevue, QC, Canada
| | - Hui Ma
- Key Laboratory of Food Nutrition and Safety, Ministry of Education of China, Tianjin University of Science and Technology, Tianjin, China
| | - Xin-Jun Du
- Key Laboratory of Food Nutrition and Safety, Ministry of Education of China, Tianjin University of Science and Technology, Tianjin, China
| | - Shuo Wang
- Key Laboratory of Food Nutrition and Safety, Ministry of Education of China, Tianjin University of Science and Technology, Tianjin, China
- Tianjin Key Laboratory of Food Science and Health, School of Medicine, Nankai University, Tianjin, China
- *Correspondence: Shuo Wang,
| | - Xiaonan Lu
- Department of Food Science and Agricultural Chemistry, Faculty of Agricultural and Environmental Sciences, McGill University, Sainte-Anne-de-Bellevue, QC, Canada
- Xiaonan Lu,
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15
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A Cutoff Determination of Real-Time Loop-Mediated Isothermal Amplification (LAMP) for End-Point Detection of Campylobacter jejuni in Chicken Meat. Vet Sci 2022; 9:vetsci9030122. [PMID: 35324850 PMCID: PMC8953776 DOI: 10.3390/vetsci9030122] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2022] [Revised: 02/22/2022] [Accepted: 03/05/2022] [Indexed: 02/01/2023] Open
Abstract
Campylobacter jejuni is one of the leading causes of foodborne illness worldwide. C. jejuni is commonly found in poultry. It is the most frequent cause of contamination and thus resulting in not only public health concerns but also economic impacts. To test for this bacterial contamination in food processing plants, this study attempted to employ a simple and rapid detection assay called loop-mediated isothermal amplification (LAMP). The best cutoff value for the positive determination of C. jejuni calculated using real-time LAMP quantification cycle (Cq) was derived from the receiver operating characteristic (ROC) curve modeling. The model showed an area under curve (AUC) of 0.936 (95% Wald CI: 0.903–0.970). Based on Youden’s J statistic, the optimal cutoff value which had the highest sensitivity and specificity from the model was calculated as 18.07. The LAMP assay had 96.9% sensitivity, 95.8% specificity, and 93.9 and 97.9% positive and negative predictive values, respectively, compared to a standard culture approach for C. jejuni identification. Among all non-C. jejuni strains, the LAMP assay gave each of 12.5% false-positive results to C. coli and E. coli (1 out of 8 samples). The assay can detect C. jejuni at the lowest concentration of 103 CFU/mL. Our results suggest a preliminary indicator for the application of end-point LAMP assays, such as turbidity and UV fluorescence tests, to detect C. jejuni in field operations. The LAMP assay is an alternative screening test for C. jejuni contamination in food samples. The method provides a rapid detection, which requires only 9 min with a cutoff value of Cq. We performed the extraction of DNA from pure cultures and the detection of C. jejuni using the LAMP assay within 3 h. However, we were not able to reduce the time for the process of enrichment involved in our study. Therefore, we suggest that alternative enrichment media and rapid DNA extraction methods should be considered for further study. Compared to other traditional methods, our proposed assay requires less equipment and time, which is applicable at any processing steps in the food production chain.
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16
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Harder CB, Persson S, Christensen J, Ljubic A, Nielsen EM, Hoorfar J. Molecular diagnostics of Salmonella and Campylobacter in human/animal fecal samples remain feasible after long-term sample storage without specific requirements. AIMS Microbiol 2022; 7:399-414. [PMID: 35071939 PMCID: PMC8712530 DOI: 10.3934/microbiol.2021024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 09/05/2021] [Indexed: 11/27/2022] Open
Abstract
Rapid advances in the development of sequencing technologies, numbers of commercial providers and diminishing costs have made DNA-based identification and diagnostics increasingly accessible to doctors and laboratories, eliminating the need for local investments in expensive technology and training or hiring of skilled technicians. However, reliable and comparable molecular analyses of bacteria in stool samples are dependent on storage and workflow conditions that do not introduce post-sampling bias, the most important factor being the need to keep the DNA at a stable detectable level. For that reason, there may remain other prohibitively costly requirements for cooling or freezing equipment or special chemical additives. This study investigates the diagnostic detectability of Salmonella and Campylobacter DNA in human, pig and chicken stool samples, stored at different temperatures and with different preservation methods. Stool samples were spiked with 106 CFU/mL of both Salmonella and Campylobacter strains stored at −20 °C, 5 °C and 20 °C (Room temperature, RT) and treated with either RNAlater, EDTA or Silica/ethanol. DNA was extracted at 9 different time points within 30 days and quantified by Qubit (total DNA) and qPCR (Salmonella and Campylobacter DNA). We found no statistically significant differences among the different preservation methods, and DNA from both species was easily detected at all time points and at all temperatures, both with and without preservation. This suggests that infections by these bacteria can be diagnosed and possibly also analysed in further detail simply by taking a stool sample in any suitable sealed container that can be transported to laboratory analysis without special storage or preservation requirements. We briefly discuss how this finding can benefit infection control in both developed and developing countries.
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Affiliation(s)
- C B Harder
- Statens Serum institut, Dept. Bacteriology, Parasitology and Fungi, Artillerivej 5, 2300 Copenhagen, Denmark.,Molecular Ecology, Microbial Ecology and Evolutionary Genetics, Lund University, Sölvegatan 37, 223 62 Lund
| | - S Persson
- Statens Serum institut, Dept. Bacteriology, Parasitology and Fungi, Artillerivej 5, 2300 Copenhagen, Denmark
| | - J Christensen
- Danish Veterinary and Food Administration, Microbiological department, Søndervang 4, 4100 Ringsted
| | - A Ljubic
- AGC Biologics, Process Transfer, Vandtårnsvej 83, 2860 Søborg, Denmark
| | - E M Nielsen
- Statens Serum institut, Dept. Bacteriology, Parasitology and Fungi, Artillerivej 5, 2300 Copenhagen, Denmark
| | - J Hoorfar
- Technical University of Denmark, National Food Institute, 2800 Kgs. Lyngby, Denmark
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17
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Stingl K, Heise J, Thieck M, Wulsten IF, Pacholewicz E, Iwobi AN, Govindaswamy J, Zeller-Péronnet V, Scheuring S, Luu HQ, Fridriksdottir V, Gölz G, Priller F, Gruntar I, Jorgensen F, Koene M, Kovac J, Lick S, Répérant E, Rohlfing A, Zawilak-Pawlik A, Rossow M, Schlierf A, Frost K, Simon K, Uhlig S, Huber I. Challenging the "gold standard" of colony-forming units - Validation of a multiplex real-time PCR for quantification of viable Campylobacter spp. in meat rinses. Int J Food Microbiol 2021; 359:109417. [PMID: 34624596 DOI: 10.1016/j.ijfoodmicro.2021.109417] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 08/01/2021] [Accepted: 09/18/2021] [Indexed: 11/26/2022]
Abstract
Campylobacter jejuni is the leading bacterial food-borne pathogen in Europe. Despite the accepted limits of cultural detection of the fastidious bacterium, the "gold standard" in food microbiology is still the determination of colony-forming units (CFU). As an alternative, a live/dead differentiating qPCR has been established, using propidium monoazide (PMA) as DNA-intercalating crosslink agent for inactivating DNA from dead, membrane-compromised cells. The PMA treatment was combined with the addition of an internal sample process control (ISPC), i.e. a known number of dead C. sputorum cells to the samples. The ISPC enables i), monitoring the effective reduction of dead cell signal by the light-activated DNA-intercalating dye PMA, and ii), compensation for potential DNA losses during processing. Here, we optimized the method for routine application and performed a full validation of the method according to ISO 16140-2:2016(E) for the quantification of live thermophilic Campylobacter spp. in meat rinses against the classical enumeration method ISO 10272-2:2017. In order to render the method applicable and cost-effective for practical application, the ISPC was lyophilized to be distributable to routine laboratories. In addition, a triplex qPCR was established to simultaneously quantify thermophilic Campylobacter, the ISPC and an internal amplification control (IAC). Its performance was statistically similar to the two duplex qPCRs up to a contamination level of 4.7 log10Campylobacter per ml of meat rinse. The limit of quantification (LOQ) of the alternative method was around 20 genomic equivalents per PCR reaction, i.e. 2.3 log10 live Campylobacter per ml of sample. The alternative method passed a relative trueness study, confirming the robustness against different meat rinses, and displayed sufficient accuracy within the limits set in ISO 16140-2:2016(E). Finally, the method was validated in an interlaboratory ring trial, confirming that the alternative method was fit for purpose with a tendency of improved repeatability and reproducibility compared to the reference method for CFU determination. Campylobacter served as a model organism, challenging CFU as "gold standard" and could help in guidance to the general acceptance of live/dead differentiating qPCR methods for the detection of food-borne pathogens.
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Affiliation(s)
- Kerstin Stingl
- German Federal Institute for Risk Assessment (BfR), Department of Biological Safety, National Reference Laboratory for Campylobacter, Berlin, Germany.
| | - Janine Heise
- German Federal Institute for Risk Assessment (BfR), Department of Biological Safety, National Reference Laboratory for Campylobacter, Berlin, Germany
| | - Maja Thieck
- German Federal Institute for Risk Assessment (BfR), Department of Biological Safety, National Reference Laboratory for Campylobacter, Berlin, Germany
| | - Imke F Wulsten
- German Federal Institute for Risk Assessment (BfR), Department of Biological Safety, National Reference Laboratory for Campylobacter, Berlin, Germany
| | - Ewa Pacholewicz
- German Federal Institute for Risk Assessment (BfR), Department of Biological Safety, National Reference Laboratory for Campylobacter, Berlin, Germany; Wageningen Bioveterinary Research, Lelystad, the Netherlands
| | - Azuka N Iwobi
- Bavarian Health and Food Safety Authority (LGL), Oberschleissheim, Germany
| | | | | | - Sandra Scheuring
- Bavarian Health and Food Safety Authority (LGL), Oberschleissheim, Germany
| | - Huong Quynh Luu
- National Institute of Veterinary Research (NIVR), Hanoi, Viet Nam
| | | | - Greta Gölz
- Freie Universitaet Berlin, Institute of Food Safety and Food Hygiene, Berlin, Germany
| | | | - Igor Gruntar
- University of Ljubljana, Institute of Microbiology and Parasitology, Ljubljana, Slovenia
| | - Frieda Jorgensen
- Public Health England, Food, Water and Environmental Laboratory - Porton, Salisbury, United Kingdom
| | - Miriam Koene
- Wageningen Bioveterinary Research, Lelystad, the Netherlands
| | - Jasna Kovac
- The Pennsylvania State University, Department of Food Science, State College, PA, United States
| | - Sonja Lick
- Max Rubner-Institute (MRI), Department of Safety and Quality of Meat, Kulmbach, Germany
| | | | - Annika Rohlfing
- Impetus GmbH & Co. Bioscience KG, Microbiology, Bremerhaven, Germany
| | - Anna Zawilak-Pawlik
- Hirszfeld Institute of Immunology and Experimental Therapy, PAS, Microbiology Department, Wroclaw, Poland
| | - Marko Rossow
- State Office for Consumer Protection Saxony-Anhalt, Department of Food Safety, Halle (Saale), Germany
| | | | | | | | | | - Ingrid Huber
- Bavarian Health and Food Safety Authority (LGL), Oberschleissheim, Germany
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18
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Vizzini P, Vidic J, Manzano M. Enrichment Free qPCR for Rapid Identification and Quantification of Campylobacter jejuni, C. coli, C. lari, and C. upsaliensis in Chicken Meat Samples by a New Couple of Primers. Foods 2021; 10:foods10102341. [PMID: 34681388 PMCID: PMC8535059 DOI: 10.3390/foods10102341] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 09/20/2021] [Accepted: 09/28/2021] [Indexed: 02/05/2023] Open
Abstract
Campylobacter is the main cause of bacterial foodborne disease and poultry meat is the principal source of human infections. Rapid methods for Campylobacter detection are urgently needed to decrease high bacterial prevalence in poultry products. In this study, we developed new primers, CampyPFw and CampyPRv, that target the 16S-23S rRNA genes of Campylobacter jejuni, C. coli, C. lari and C. upsaliensis. The primers were tested on positive and negative reference strains in pure cultures and in inoculated poultry meat samples before their application in real-time PCR (qPCR) protocol for analyzing chicken meat samples. In parallel, the samples were tested by using the ISO 10272-1:2006 method. The qPCR protocol based on CampyPFw and CampyPRv showed good sensitivity, with the limit of detection of 4.6 × 102 cells/mL in chicken samples without enrichment steps.
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Affiliation(s)
- Priya Vizzini
- Dipartimento di Scienze AgroAlimentari, Ambientali e Animali, Università di Udine, 33100 Udine, Italy;
| | - Jasmina Vidic
- AgroParisTech, INRAE, Micalis Institute, Université Paris-Saclay, 78350 Jouy en Josas, France;
| | - Marisa Manzano
- Dipartimento di Scienze AgroAlimentari, Ambientali e Animali, Università di Udine, 33100 Udine, Italy;
- Correspondence:
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19
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Bouju-Albert A, Saltaji S, Dousset X, Prévost H, Jaffrès E. Quantification of Viable Brochothrix thermosphacta in Cold-Smoked Salmon Using PMA/PMAxx-qPCR. Front Microbiol 2021; 12:654178. [PMID: 34335490 PMCID: PMC8316974 DOI: 10.3389/fmicb.2021.654178] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 06/17/2021] [Indexed: 11/17/2022] Open
Abstract
The aim of this study was to develop a rapid and accurate PMA-qPCR method to quantify viable Brochothrix thermosphacta in cold-smoked salmon. B. thermosphacta is one of the main food spoilage bacteria. Among seafood products, cold-smoked salmon is particularly impacted by B. thermosphacta spoilage. Specific and sensitive tools that detect and quantify this bacterium in food products are very useful. The culture method commonly used to quantify B. thermosphacta is time-consuming and can underestimate cells in a viable but not immediately culturable state. We designed a new PCR primer set from the single-copy rpoC gene. QPCR efficiency and specificity were compared with two other published primer sets targeting the rpoC and rpoB genes. The viability dyes PMA or PMAxx were combined with qPCR and compared with these primer sets on viable and dead B. thermosphacta cells in BHI broth and smoked salmon tissue homogenate (SSTH). The three primer sets displayed similar specificity and efficiency. The efficiency of new designed rpoC qPCR on viable B. thermosphacta cells in SSTH was 103.50%, with a linear determination coefficient (r2) of 0.998 and a limit of detection of 4.04 log CFU/g. Using the three primer sets on viable cells, no significant difference was observed between cells treated or untreated with PMA or PMAxx. When dead cells were used, both viability dyes suppressed DNA amplification. Nevertheless, our results did not highlight any difference between PMAxx and PMA in their efficiency to discriminate viable from unviable B. thermosphacta cells in cold-smoked salmon. Thus, this study presents a rapid, specific and efficient rpoC-PMA-qPCR method validated in cold-smoked salmon to quantify viable B. thermosphacta in foods.
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20
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Thornval NR, Hoorfar J. Progress in detection of Campylobacter in the food production chain. Curr Opin Food Sci 2021. [DOI: 10.1016/j.cofs.2020.12.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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21
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How to Evaluate Non-Growing Cells-Current Strategies for Determining Antimicrobial Resistance of VBNC Bacteria. Antibiotics (Basel) 2021; 10:antibiotics10020115. [PMID: 33530321 PMCID: PMC7912045 DOI: 10.3390/antibiotics10020115] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 01/19/2021] [Accepted: 01/22/2021] [Indexed: 12/17/2022] Open
Abstract
Thanks to the achievements in sanitation, hygiene practices, and antibiotics, we have considerably improved in our ongoing battle against pathogenic bacteria. However, with our increasing knowledge about the complex bacterial lifestyles and cycles and their plethora of defense mechanisms, it is clear that the fight is far from over. One of these resistance mechanisms that has received increasing attention is the ability to enter a dormancy state termed viable but non-culturable (VBNC). Bacteria that enter the VBNC state, either through unfavorable environmental conditions or through potentially lethal stress, lose their ability to grow on standard enrichment media, but show a drastically increased tolerance against antimicrobials including antibiotics. The inability to utilize traditional culture-based methods represents a considerable experimental hurdle to investigate their increased antimicrobial resistance and impedes the development and evaluation of effective treatments or interventions against bacteria in the VBNC state. Although experimental approaches were developed to detect and quantify VBNCs, only a few have been utilized for antimicrobial resistance screening and this review aims to provide an overview of possible methodological approaches.
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22
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Listeria monocytogenes Assessment in a Ready-to-Eat Salad Shelf-Life Study Using Conventional Culture-Based Methods, Genetic Profiling, and Propidium Monoazide Quantitative PCR. Foods 2021; 10:foods10020235. [PMID: 33498826 PMCID: PMC7911829 DOI: 10.3390/foods10020235] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 01/16/2021] [Accepted: 01/20/2021] [Indexed: 12/22/2022] Open
Abstract
Listeriosis is almost entirely transmitted through foods contaminated with Listeria monocytogenes. Ready-to-eat foods present a particular challenge due to their long refrigerated shelf-life, not requiring any heat treatment before consumption. In this work, a shelf-life assessment of an industrially produced ready-to-eat salad was performed using conventional culture-based and molecular methods. L. monocytogenes isolates were confirmed and serogrouped using multiplex PCR, and genetic subtyping was performed by pulsed-field gel electrophoresis (PFGE). PMAxx-qPCR was used as an alternative method for L. monocytogenes quantification in foods. Salad samples were kept at 4 °C, 12 °C, and 16 °C for eight days and analysed. At 4 °C, acceptable results were obtained considering hygiene indicators, i.e., Enterobacteriaceae (ranging from 3.55 ± 0.15 log cfu/g to 5.39 ± 0.21 log cfu/g) and aerobic mesophilic colony counts (5.91 ± 0.90 log cfu/g to 9.41 ± 0.58 log cfu/g) throughout the study, but the same did not happen at 12 °C and 16 °C. L. monocytogenes culture-based quantification exhibited low numbers (<1 log cfu/g) for all temperatures. From 30 presumptive isolates, 10 (33.3%) were confirmed as L. monocytogenes with the majority belonging to serogroup IVb. PFGE subtyping showed that 7 of the 10 L. monocytogenes isolates had 100% of pulsotype similarity, suggesting a possible common contamination source. PMAxx-qPCR revealed a statistically higher L. monocytogenes quantification (>3 log cfu/g) when compared to the conventional culture-based method, suggesting viable but non-culturable forms. Taken together, results underline the need to combine conventional methods with more sensitive, specific, and rapid ones for L. monocytogenes assessment in ready-to-eat foods shelf-life studies to reduce the potential risk for consumers.
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23
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Szott V, Friese A. Emission Sources of Campylobacter from Agricultural Farms, Impact on Environmental Contamination and Intervention Strategies. Curr Top Microbiol Immunol 2021; 431:103-125. [PMID: 33620650 DOI: 10.1007/978-3-030-65481-8_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/24/2023]
Abstract
Although extensive research has been carried out to describe the transmission pathways of Campylobacter entering livestock farms, the role of livestock farms as source of Campylobacter contamination of the environment is still poorly investigated. It is assumed that Campylobacter-positive livestock farms contribute to an environmental contamination, depending on the animal species on the farm, their Campylobacter status, the housing system, manure management as well as their general farm hygienic and biosecurity management. Different emission sources, like manure, air, water, insects and rodents as well as personnel, including equipment and vehicles, contribute to Campylobacter emission into the environment. Even though Campylobacter are rather fastidious bacteria, they are able to survive in the environment for even a longer period of time, when environmental conditions enable survival in specific niches. We conclude that a significant reduction of Campylobacter emission in the environment can be successfully achieved if various intervention strategies, depending on the farm type, are applied simultaneously, including proper general and personal hygiene, establishing of hygienic barriers, insect controls, manure management and hygienization of stables, barns and exhaust air.
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Affiliation(s)
- Vanessa Szott
- Institute for Animal Hygiene and Environmental Health, Free University Berlin, Centre for Infection Medicine, Robert-von-Ostertag-Str. 7-13, 14163, Berlin, Germany
| | - Anika Friese
- Institute for Animal Hygiene and Environmental Health, Free University Berlin, Centre for Infection Medicine, Robert-von-Ostertag-Str. 7-13, 14163, Berlin, Germany.
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24
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Alter T, Reich F. Management Strategies for Prevention of Campylobacter Infections Through the Poultry Food Chain: A European Perspective. Curr Top Microbiol Immunol 2021; 431:79-102. [PMID: 33620649 DOI: 10.1007/978-3-030-65481-8_4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/08/2022]
Abstract
Numerous studies point out that at present, a complete elimination of Campylobacter species in the poultry food chain is not feasible. Thus, the current aim should be to establish control measures and intervention strategies to minimize the occurrence of Campylobacter spp. in livestock (esp. poultry flocks) and to reduce the quantitative Campylobacter burden along the food chain in animals and subsequently in foods. The most effective measures to mitigate Campylobacter focus on the primary production stage. Nevertheless, measures applied during slaughter and processing complement the general meat hygiene approaches by reducing fecal contamination during slaughtering and processing and as a consequence help to reduce Campylobacter in poultry meat. Such intervention measures at slaughter and processing level would include general hygienic improvements, technological innovations and/or decontamination measures that are applied at single slaughter or processing steps. In particular, approaches that do not focus on a single intervention measure would need to be based on a thorough process of evaluation, and potential combinatory effects have to be modeled and tested. Finally, the education of all stakeholders (including retailers, food handlers and consumers) is required and will help to increase awareness for the presence of foodborne pathogens in raw meat and meat products and can thus aid in the development of the required good kitchen hygiene.
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Affiliation(s)
- Thomas Alter
- Center for Veterinary Public Health, Institute of Food Safety and Food Hygiene, Free University Berlin, Koenigsweg 69, Berlin, 14163, Germany.
| | - Felix Reich
- German Federal Institute for Risk Assessment, Max-Dohrn-Strasse 8-10, Berlin, 10589, Germany
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A Multicenter Proposal for a Fast Tool To Screen Biosecure Chicken Flocks for the Foodborne Pathogen Campylobacter. Appl Environ Microbiol 2020; 86:AEM.01051-20. [PMID: 32769183 DOI: 10.1128/aem.01051-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 08/02/2020] [Indexed: 11/20/2022] Open
Abstract
The present multicenter study aimed at assessing the performance of air sampling as a novel method for monitoring Campylobacter in biosecure poultry farms. We compared, using a harmonized procedure, the bacteriological isolation protocol (ISO 10272-1:2017) and a real-time PCR method used on air filter samples. Air samples and boot swabs were collected from 62 biosecure flocks from five European countries during the summer of 2019. For air filters, the frequency of PCR-positive findings was significantly higher (n = 36; 58%) than that obtained with the cultivation methods (P < 0.01; standardized residuals). The cultivation protocols (one with Bolton enrichment and one with Preston enrichment) were comparable to each other but returned fewer positive samples (0 to 8%). The association between type of sample and frequency of PCR-positive findings was statistically confirmed (P < 0.01; Fisher´s exact test), although no culture-positive air filters were detected using direct plating. For the boot swabs, the highest number of positive samples were detected after enrichment in Preston broth (n = 23; 37%), followed by direct plating after homogenization in Preston (n = 21; 34%) or Bolton broth (n = 20; 32%). It is noteworthy that the flocks in Norway, a country known to have low Campylobacter prevalence in biosecure chicken flocks, tested negative for Campylobacter by the new sensitive approach. In conclusion, air sampling combined with real-time PCR is proposed as a multipurpose, low-cost, and convenient screening method that can be up to four times faster and four times more sensitive than the current boot-swab testing scheme used for screening biosecure chicken production.IMPORTANCE Campylobacter bacteria are the cause of the vast majority of registered cases of foodborne illness in the industrialized world. In fact, the bacteria caused 246,571 registered cases of foodborne illness in 2018, which equates to 70% of all registered cases in Europe that year. An important tool to prevent campylobacters from making people sick is good data on where in the food chain the bacterium is present. The present study reports a new test method that quadruples the likelihood of identifying campylobacter-positive chicken flocks. It is important to identify campylobacter-positive flocks before they arrive at the slaughterhouse, because negative flocks can be slaughtered first in order to avoid cross-contamination along the production line.
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Si Y, Grazon C, Clavier G, Rieger J, Tian Y, Audibert JF, Sclavi B, Méallet-Renault R. Fluorescent Copolymers for Bacterial Bioimaging and Viability Detection. ACS Sens 2020; 5:2843-2851. [PMID: 32786389 DOI: 10.1021/acssensors.0c00981] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Novel fluorescent labels with high photostability and high biocompatibility are required for microbiological imaging and detection. Here, we present a green fluorescent polymer chain (GFPC), designed to be nontoxic and water-soluble, for multicolor bioimaging and real-time bacterial viability determination. The copolymer is synthesized using a straightforward one-pot reversible addition-fragmentation chain-transfer (RAFT) polymerization technique. We show that GFPC does not influence bacterial growth and is stable for several hours in a complex growth medium and in the presence of bacteria. GFPC allows the labeling of the bacterial cytoplasm for multicolor bacterial bioimaging applications. It can be used in combination with propidium iodide (PI) to develop a rapid and reliable protocol to distinguish and quantify, in real time, by flow cytometry, live and dead bacteria.
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Affiliation(s)
- Yang Si
- Université Paris-Saclay, ENS Paris-Saclay, CNRS, PPSM, 91190 Gif-sur-Yvette, France
- Université Paris-Saclay, ENS Paris-Saclay, CNRS, LBPA, 91190 Gif-sur-Yvette, France
| | - Chloé Grazon
- Université Paris-Saclay, ENS Paris-Saclay, CNRS, PPSM, 91190 Gif-sur-Yvette, France
| | - Gilles Clavier
- Université Paris-Saclay, ENS Paris-Saclay, CNRS, PPSM, 91190 Gif-sur-Yvette, France
| | - Jutta Rieger
- Sorbonne Université, CNRS, Institut Parisien de Chimie Moléculaire, UMR 8232, Equipe Chimie des Polymères, 75252 Paris, France
| | - Yayang Tian
- Université Paris-Saclay, ENS Paris-Saclay, CNRS, PPSM, 91190 Gif-sur-Yvette, France
| | | | - Bianca Sclavi
- Université Paris-Saclay, ENS Paris-Saclay, CNRS, LBPA, 91190 Gif-sur-Yvette, France
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Techathuvanan C, D'Souza DH. Propidium monoazide for viable Salmonella enterica detection by PCR and LAMP assays in comparison to RNA-based RT-PCR, RT-LAMP, and culture-based assays. J Food Sci 2020; 85:3509-3516. [PMID: 32964461 DOI: 10.1111/1750-3841.15459] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Revised: 08/25/2020] [Accepted: 08/26/2020] [Indexed: 12/13/2022]
Abstract
Rapid and sensitive detection of live/infectious foodborne pathogens is urgently needed in order to prevent outbreaks and food recalls. This study aimed to (1) evaluate the incorporation of propidium monoazide (PMA) into PCR or LAMP assays to selectively detect viable Salmonella Enteritidis following sublethal heat or UV treatment, and autoclave sterilization; and (2) compare the detection of PMA-PCR and PMA-LAMP to DNA-based PCR and LAMP (without PMA), RNA-based RT-PCR and RT-LAMP, and culture-based methods. Nucleic acids (DNA or RNA) from 1-mL S. Enteritidis samples were used for PCR, RT-PCR, LAMP, and RT-LAMP assays. Serially diluted samples were plated on Xylose Lysine Tergitol-4 agar for cultural enumeration. Comparable detection of overnight cultured S. Enteritidis was obtained by PMA-PCR, PCR, and RT-PCR, though 1 to 2 log less sensitive than cultural assays. PMA-LAMP and RT-LAMP showed similar detection of overnight cultures, being 1 to 2 log less sensitive than the LAMP assay, and ∼4 log less than culture-based detection. Autoclaved S. Enteritidis did not test positive by RNA-based methods or PMA-PCR, but PMA-LAMP showed detection of 1 log CFU/mL. PMA-PCR and RT-PCR showed comparable detection of sublethal heat-treated cells to cultural assays, while PMA-LAMP showed 1 to 2 log less detection. Our results suggest that PMA-PCR and PMA-LAMP assays are not suitable for selective viable cell detection after UV treatment. While PMA-LAMP assay needs optimization, PMA-PCR shows promise for live/viable S. Enteritidis detection. PMA-PCR shows potential for routine testing in the food industry with results within 1-day, albeit depending on the inactivation method employed.
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Affiliation(s)
- Chayapa Techathuvanan
- Department of Food Science, University of Tennessee, 2605 River Drive, Knoxville, TN, 37996-4591, U.S.A
| | - Doris Helen D'Souza
- Department of Food Science, University of Tennessee, 2605 River Drive, Knoxville, TN, 37996-4591, U.S.A
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Dzierzon J, Oswaldi V, Merle R, Langkabel N, Meemken D. High Predictive Power of Meat Juice Serology on the Presence of Hepatitis E Virus in Slaughter Pigs. Foodborne Pathog Dis 2020; 17:687-692. [PMID: 32412857 DOI: 10.1089/fpd.2020.2797] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Hepatitis E virus (HEV) as a zoonotic agent can be responsible for an acute hepatitis in humans, which is usually self-limiting. Progression toward a chronic stage is possible, especially in immunocompromised patients. In the past decade, the number of hepatitis E cases in humans in Germany has increased enormously to 3491 cases in 2018. Domestic pigs have been identified as a main animal reservoir and the consumption of raw and undercooked pork products, that is, livers or liver products, meat or meat products, is known as a potential risk of foodborne HEV infection. The aim of this study was to determine whether serological tests are appropriate to predict the occurrence of HEV in the liver and muscle of domestic pigs in Germany. In 2018, samples of meat juice, liver, and ham muscle were collected from 250 fattening pigs at an abattoir in North West Germany. Samples were analyzed for the presence of HEV antibodies using enzyme-linked immunosorbent assay respectively for the presence of HEV RNA using real-time reverse transcription-polymerase chain reaction. In total, 62% (155/250) of the meat juice samples were positive for HEV antibodies at a single animal basis. At herd level, 72% (18/25) of the herds were seropositive. The HEV prevalence in the liver was 17.2% (43/250). Each positive liver sample originated from seropositive herds respectively from HEV seropositive pigs. This study demonstrates for the first time the significant correlation between a positive HEV serology and the occurrence of HEV RNA in the liver of slaughter pigs (χ2 = 31.83; p < 0.001), highlighting the significant predictive power of positive serological results on the occurrence of HEV RNA in the liver.
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Affiliation(s)
- Janine Dzierzon
- Institute of Food Safety and Food Hygiene, Working Group Meat Hygiene, Freie Universität Berlin, Department of Veterinary Medicine, Berlin, Germany
| | - Verena Oswaldi
- Institute of Food Safety and Food Hygiene, Working Group Meat Hygiene, Freie Universität Berlin, Department of Veterinary Medicine, Berlin, Germany
| | - Roswitha Merle
- Institute for Veterinary Epidemiology and Biostatistics, Freie Universität Berlin, Department of Veterinary Medicine, Berlin, Germany
| | - Nina Langkabel
- Institute of Food Safety and Food Hygiene, Working Group Meat Hygiene, Freie Universität Berlin, Department of Veterinary Medicine, Berlin, Germany
| | - Diana Meemken
- Institute of Food Safety and Food Hygiene, Working Group Meat Hygiene, Freie Universität Berlin, Department of Veterinary Medicine, Berlin, Germany
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Ni J, Hatori S, Wang Y, Li YY, Kubota K. Uncovering Viable Microbiome in Anaerobic Sludge Digesters by Propidium Monoazide (PMA)-PCR. MICROBIAL ECOLOGY 2020; 79:925-932. [PMID: 31701171 DOI: 10.1007/s00248-019-01449-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2019] [Accepted: 10/09/2019] [Indexed: 06/10/2023]
Abstract
Use of anaerobic sludge digester is a common practice around the world for solids digestion and methane generation from municipal sewage sludge. Understanding microbial community structure is vital to get better insight into the anaerobic digestion process and to gain better process control. However, selective analysis of viable microorganisms is limited by DNA-based assays. In this study, propidium monoazide (PMA)-PCR with 16S rRNA gene sequencing analysis was used to distinguish live and dead microorganisms based on cell membrane integrity. Microbial community structures of PMA-treated and PMA-untreated anaerobic digester sludge samples were compared. Quantitative PCR revealed that 5-30% of the rRNA genes were derived from inactive or dead cells in anaerobic sludge digesters. This caused a significant decrease in the numbers of operational taxonomic units and Chao1 and Shannon indices compared with that of the PMA-untreated sludge. Microbial community analysis showed that majority of the viable microbiome consisted of Euryarchaeota, Bacteroidetes, Deltaproteobacteria, Chloroflexi, Firmicutes, WWE1, Spirochaetes, Synergistetes, and Caldiserica. On the other hand, after the PMA treatment, numbers of Alphaproteobacteria and Betaproteobacteria declined. These were considered residual microbial members. The network analysis also revealed a relationship among the OTUs belonging to WWE1 and Bacteroidales. PMA-PCR-based 16S rRNA gene sequencing analysis is an effective tool for uncovering viable microbiome in complex environmental samples.
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Affiliation(s)
- Jialing Ni
- Department of Civil and Environmental Engineering, Tohoku University, 6-6-06 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi, 980-8579, Japan
| | - Shingo Hatori
- Department of Civil and Environmental Engineering, Tohoku University, 6-6-06 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi, 980-8579, Japan
| | - Yin Wang
- Institute of Urban Environment, Chinese Academy of Sciences, 1799 JiMei Road, Xiamen, 361021, China
| | - Yu-You Li
- Department of Civil and Environmental Engineering, Tohoku University, 6-6-06 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi, 980-8579, Japan
| | - Kengo Kubota
- Department of Civil and Environmental Engineering, Tohoku University, 6-6-06 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi, 980-8579, Japan.
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Zhao L, Lv X, Cao X, Zhang J, Gu X, Zeng H, Wang L. Improved quantitative detection of VBNC Vibrio parahaemolyticus using immunomagnetic separation and PMAxx-qPCR. Food Control 2020. [DOI: 10.1016/j.foodcont.2019.106962] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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31
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Campylobacter in chicken - Critical parameters for international, multicentre evaluation of air sampling and detection methods. Food Microbiol 2020; 90:103455. [PMID: 32336358 DOI: 10.1016/j.fm.2020.103455] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Revised: 11/18/2019] [Accepted: 02/04/2020] [Indexed: 12/21/2022]
Abstract
The present pilot study aimed at evaluating air sampling as a novel method for monitoring Campylobacter in poultry farms. We compared the bacteriological isolation of Campylobacter from boot swabs and air filter samples using ISO 10272-1:2017. A secondary aim was to evaluate the use of molecular methods, i.e. real time PCR, on the same sample set. Samples from 44 flocks from five European countries were collected, and included air samples, in parallel with boot swabs. Campylobacter spp. was isolated from seven of 44 boot swabs from three of five partners using the enrichment method. Two of these positive boot swab samples had corresponding positive air samples. Using enrichment, one positive air sample was negative in the corresponding boot swabs, but Campylobacter spp. was isolated from direct plating of the boot swab sample. One partner isolated Campylobacter spp. from six of 10 boot swabs using direct plating. Overall, 33 air filter samples were screened directly with PCR, returning 14 positive results. In conclusion, there was a lack of correspondence between results from analysis of boot swabs and air filters using ISO 10272-1:2017. In contrast, the combination of air filters and direct real-time PCR might be a way forward. Despite the use of the detailed ISO protocols, there were still sections that could be interpreted differently among laboratories. Air sampling may turn into a multi-purpose and low-cost sampling method that may be integrated into self-monitoring programs.
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32
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Lv R, Wang K, Feng J, Heeney DD, Liu D, Lu X. Detection and Quantification of Viable but Non-culturable Campylobacter jejuni. Front Microbiol 2020; 10:2920. [PMID: 31998253 PMCID: PMC6965164 DOI: 10.3389/fmicb.2019.02920] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Accepted: 12/04/2019] [Indexed: 12/14/2022] Open
Abstract
Campylobacter can enter a viable but non-culturable (VBNC) state to evade various stresses, and this state is undetectable using traditional microbiological culturing techniques. These VBNC bacterial cells retain metabolism and demonstrate pathogenic potential due to their ability to resuscitate under favorable conditions. Rapid and accurate determination of VBNC Campylobacter is critical to further understand the induction and resuscitation of the dormancy state of this microbe in the agri-food system. Here, we integrated propidium monoazide (PMA) with real-time polymerase chain reaction (qPCR) targeting the rpoB gene to detect and quantify Campylobacter jejuni in the VBNC state. First, we optimized the concentration of PMA (20 μM) that could significantly inhibit the amplification of dead cells by qPCR with no significant interference on the amplification of viable cell DNA. PMA-qPCR was highly specific to C. jejuni with a limit of detection (LOD) of 2.43 log CFU/ml in pure bacterial culture. A standard curve for C. jejuni cell concentrations was established with the correlation coefficient of 0.9999 at the linear range of 3.43 to 8.43 log CFU/ml. Induction of C. jejuni into the VBNC state by osmotic stress (i.e., 7% NaCl) was rapid (<48 h) and effective (>10% population). The LOD of PMA-qPCR for VBNC C. jejuni exogenously applied to chicken breasts was 3.12 log CFU/g. In conclusion, PMA-qPCR is a rapid, specific, and sensitive method for the detection and quantification of VBNC C. jejuni in poultry products. This technique can give insight into the prevalence of VBNC Campylobacter in the environment and agri-food production system.
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Affiliation(s)
- Ruiling Lv
- Food, Nutrition, and Health Program, Faculty of Land and Food Systems, The University of British Columbia, Vancouver, BC, Canada.,College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou, China
| | - Kaidi Wang
- Food, Nutrition, and Health Program, Faculty of Land and Food Systems, The University of British Columbia, Vancouver, BC, Canada
| | - Jinsong Feng
- Food, Nutrition, and Health Program, Faculty of Land and Food Systems, The University of British Columbia, Vancouver, BC, Canada
| | - Dustin D Heeney
- Food, Nutrition, and Health Program, Faculty of Land and Food Systems, The University of British Columbia, Vancouver, BC, Canada
| | - Donghong Liu
- College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou, China
| | - Xiaonan Lu
- Food, Nutrition, and Health Program, Faculty of Land and Food Systems, The University of British Columbia, Vancouver, BC, Canada
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Mason MG, Blackall PJ, Botella JR, Templeton JM. An easy-to-perform, culture-free Campylobacter point-of-management assay for processing plant applications. J Appl Microbiol 2019; 128:620-629. [PMID: 31705613 PMCID: PMC7027919 DOI: 10.1111/jam.14509] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 10/22/2019] [Accepted: 11/07/2019] [Indexed: 12/16/2022]
Abstract
Aims Current culture‐based methods for detection and determination of Campylobacter levels on processed chickens takes at least 2 days. Here we sought to develop a new complete, low‐cost and rapid (approximately 2·5 h) detection system requiring minimal operator input. Methods and Results We observed a strong correlation between culture‐based cell counts and our ability to detect either Campylobacter jejuni or Campylobacter coli by loop‐mediated isothermal amplification from the same samples. This knowledge was used to develop a rapid and simple five‐step assay to quantify Campylobacter, which was subsequently assessed for its specificity, reproducibility and accuracy in quantifying Campylobacter levels from processed chickens. The assay was found to be highly specific for C. jejuni and C. coli and was capable of distinguishing between samples that are either within or exceeding the industry set target of 6000 Campylobacter colony forming units (CFU) per carcass (equivalent to 12 CFU per ml of chicken rinse) with >90% accuracy relative to culture‐based methods. Conclusions Our method can reliably quantify Campylobacter counts of processed chickens with an accuracy comparable to culture‐based assays but provides results within hours as opposed to days. Significance and Impact of the Study The research presented here will help improve food safety by providing fast Campylobacter detection that will enable the implementation of real‐time risk management strategies in poultry processing plants to rapidly test processed chickens and identify effective intervention strategies. This technology is a powerful tool that can be easily adapted for other organisms and thus could be highly beneficial for a broad range of industries.
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Affiliation(s)
- M G Mason
- Plant Genetic Engineering Laboratory, School of Agriculture and Food Sciences, The University of Queensland, St. Lucia, Qld, Australia
| | - P J Blackall
- Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, St. Lucia, Qld, Australia
| | - J R Botella
- Plant Genetic Engineering Laboratory, School of Agriculture and Food Sciences, The University of Queensland, St. Lucia, Qld, Australia
| | - J M Templeton
- Animal Science, Department of Agriculture and Fisheries, EcoSciences Precinct, Dutton Park, Qld, Australia
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Quyen TL, Nordentoft S, Vinayaka AC, Ngo TA, Engelsmenn P, Sun Y, Madsen M, Bang DD, Wolff A. A Sensitive, Specific and Simple Loop Mediated Isothermal Amplification Method for Rapid Detection of Campylobacter spp. in Broiler Production. Front Microbiol 2019; 10:2443. [PMID: 31708907 PMCID: PMC6821646 DOI: 10.3389/fmicb.2019.02443] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Accepted: 10/10/2019] [Indexed: 01/01/2023] Open
Abstract
Campylobacteriosis is one of the most common foodborne diseases worldwide. Two Campylobacter species - C. jejuni and C. coli in poultry and poultry products are considered to be the main source of human campylobacteriosis. Therefore, studying Campylobacter status in poultry flocks is needed to prevent transmission of disease and reduce human risk, health cost, and economic losses. In this study, we adapted and used a Loop-Mediated Isothermal Amplification (LAMP) assay for specific, sensitive, simple and cost-effective rapid detection of C. jejuni and C. coli in the poultry production chain. Amplified LAMP products were detected using a small, low-cost portable commercial blue LED transilluminator and a direct visual detection strategy was demonstrated. By using optimized conditions for amplification a limit of detection (LOD) of 50 CFU/ml was achieved for testing of C. jejuni and C. coli in spiked chicken feces without enrichment. The method took 60-70 min from receiving the samples to the final results (including 30 min for amplification). The optimized LAMP showed a relative accuracy of 98.4%, a specificity of 97.9%, and a sensitivity of 100% in comparison to real-time PCR method. Cohen's kappa index also showed an excellent agreement (0.94) between the two methods. The results showed that the method is specific, sensitive and is suitable to develop for rapid detection of Campylobacter spp. at poultry production.
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Affiliation(s)
- Than Linh Quyen
- Department of Biotechnology and Biomedicine, Technical University of Denmark (DTU-Bioengineering), Lyngby, Denmark
| | - Steen Nordentoft
- National Food Institute, Technical University of Denmark (DTU-Food), Lyngby, Denmark
| | | | - Tien Anh Ngo
- National Food Institute, Technical University of Denmark (DTU-Food), Lyngby, Denmark
| | - Pia Engelsmenn
- National Food Institute, Technical University of Denmark (DTU-Food), Lyngby, Denmark
| | - Yi Sun
- Department of Health Technology, Technical University of Denmark (DTU-Health Tech), Lyngby, Denmark
| | - Mogens Madsen
- Department of Biotechnology and Biomedicine, Technical University of Denmark (DTU-Bioengineering), Lyngby, Denmark
| | - Dang Duong Bang
- National Food Institute, Technical University of Denmark (DTU-Food), Lyngby, Denmark
| | - Anders Wolff
- Department of Biotechnology and Biomedicine, Technical University of Denmark (DTU-Bioengineering), Lyngby, Denmark
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Lazou TP, Iossifidou EG, Gelasakis AI, Chaintoutis SC, Dovas CI. Viability Quantitative PCR Utilizing Propidium Monoazide, Spheroplast Formation, and Campylobacter coli as a Bacterial Model. Appl Environ Microbiol 2019; 85:e01499-19. [PMID: 31420339 PMCID: PMC6805072 DOI: 10.1128/aem.01499-19] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Accepted: 08/09/2019] [Indexed: 01/09/2023] Open
Abstract
A viability quantitative PCR (qPCR) utilizing propidium monoazide (PMA) is presented for rapid quantification of viable cells using the foodborne pathogen Campylobacter coli as a bacterial model. It includes optimized spheroplast formation via lysozyme and EDTA, induction of a mild osmotic shock for enhancing the selective penetration of PMA into dead cells, and exploitation of an internal sample process control (ISPC) involving cell inactivation to assess residual false-positive signals within each sample. Spheroplasting of bacteria in exponential phase did not permit PMA entrance into viable cells since a strong linear relationship was detected between simple qPCR and PMA-qPCR quantification, and no differences were observed regardless of whether spheroplasting was utilized. The PMA-qPCR signal suppression of dead cells was elevated using spheroplast formation. With regard to the ISPC, cell inactivation by hydrogen peroxide resulted in higher signal suppression during qPCR than heat inactivation did. Viability quantification of C. coli cells by optimized spheroplasting-PMA-qPCR with ISPC was successfully applied in an aging pure culture under aerobic conditions and artificially inoculated meat. The same method exhibited a high linear range of quantification (1.5 to 8.5 log10 viable cells ml-1), and results were highly correlated with culture-based enumeration. PMA-qPCR quantification of viable cells can be affected by their rigidity, age, culture media, and niches, but spheroplast formation along with osmotic shock and the use of a proper ISPC can address such variations. The developed methodology could detect cells in a viable-but-nonculturable state and might be utilized for the quantification of other Gram-negative bacteria.IMPORTANCE There is need for rapid and accurate methods to detect viable bacterial cells of foodborne pathogens. Conventional culture-based methods are time-consuming and unable to detect bacteria in a viable-but-nonculturable state. The high sensitivity and specificity of the quantitative PCR (qPCR) are negated by its inability to differentiate the DNAs from viable and dead cells. The combination of propidium monoazide (PMA), a DNA-intercalating dye, with qPCR assays is promising for detection of viable cells. Despite encouraging results, these assays still encounter various challenges, such as false-positive signals by dead cells and the lack of an internal control identifying these signals per sample. The significance of our research lies in enhancing the selective entrance of PMA into dead Campylobacter coli cells via spheroplasting and in developing an internal sample process control, thus delivering reliable results in pure cultures and meat samples, approaches that can be applicable to other Gram-negative pathogens.
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Affiliation(s)
- Thomai P Lazou
- Laboratory of Hygiene of Foods of Animal Origin-Veterinary Public Health, School of Veterinary Medicine, Faculty of Health Sciences, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Eleni G Iossifidou
- Laboratory of Hygiene of Foods of Animal Origin-Veterinary Public Health, School of Veterinary Medicine, Faculty of Health Sciences, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Athanasios I Gelasakis
- Laboratory of Anatomy and Physiology of Farm Animals, Department of Animal Science, School of Animal Biosciences, Agricultural University of Athens, Athens, Greece
| | - Serafeim C Chaintoutis
- Diagnostic Laboratory, School of Veterinary Medicine, Faculty of Health Sciences, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Chrysostomos I Dovas
- Diagnostic Laboratory, School of Veterinary Medicine, Faculty of Health Sciences, Aristotle University of Thessaloniki, Thessaloniki, Greece
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Dorn-In S, Gareis M, Schwaiger K. Differentiation of live and dead Mycobacterium tuberculosis complex in meat samples using PMA qPCR. Food Microbiol 2019; 84:103275. [PMID: 31421753 DOI: 10.1016/j.fm.2019.103275] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Revised: 07/15/2019] [Accepted: 07/16/2019] [Indexed: 01/28/2023]
Abstract
The causative agents of zoonotic bovine tuberculosis (bTB), Mycobacterium bovis and M. caprae, are members of the M. tuberculosis complex (MTC). Wildlife such as red deer infected with bTB are often without pathological findings, thus meat thereof may be classified as safe for human consumption. The culturing of MTC is time consuming and inappropriate to be applied with fresh meat and food. Therefore, a rapid method "PMA qPCR" to differentiate living and dead cells of MTC was developed in this study. By treating with 50 μM PMA™ dye, dead M. bovis BCG (≤104 cells/ml meat suspension) could be completely discriminated and was not detected by specific MTC PCR. The limit of detection of MTC without treatment with PMA™ dye was 10 cells/ml. All 50 venison samples obtained for field study purposes were negative for MTC. However, 40% were slightly PCR positive for non-TBC mycobacteria. By culturing using selective enrichment, one single colony of M. avium was isolated. This is the first report on the isolation of M. avium from venison. Considering the difficulties of diagnosing mycobacteria in various matrices, the developed PMA qPCR is applicable for the differentiation of dead and living cells of MTC in meat samples.
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Affiliation(s)
- Samart Dorn-In
- Chair of Food Safety, Faculty of Veterinary Medicine, LMU Munich, Schoenleutnerstr. 8, 85764, Oberschleissheim, Germany.
| | - Manfred Gareis
- Chair of Food Safety, Faculty of Veterinary Medicine, LMU Munich, Schoenleutnerstr. 8, 85764, Oberschleissheim, Germany
| | - Karin Schwaiger
- Chair of Food Safety, Faculty of Veterinary Medicine, LMU Munich, Schoenleutnerstr. 8, 85764, Oberschleissheim, Germany
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Laidlaw AM, Gänzle MG, Yang X. Comparative assessment of qPCR enumeration methods that discriminate between live and dead Escherichia coli O157:H7 on beef. Food Microbiol 2019; 79:41-47. [DOI: 10.1016/j.fm.2018.11.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2018] [Revised: 11/05/2018] [Accepted: 11/13/2018] [Indexed: 11/28/2022]
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Telli AE, Doğruer Y. Discrimination of viable and dead Vibrio parahaemolyticus subjected to low temperatures using Propidium Monoazide - Quantitative loop mediated isothermal amplification (PMA-qLAMP) and PMA-qPCR. Microb Pathog 2019; 132:109-116. [PMID: 31034964 DOI: 10.1016/j.micpath.2019.04.029] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Revised: 03/14/2019] [Accepted: 04/17/2019] [Indexed: 11/29/2022]
Abstract
The aim of this study was to determine the effect of cold (4 °C) and subzero (-18 °C, -45 °C) temperatures on the occurrence time of membrane damage to provide Propidium Monoazide (PMA) penetration of Vibrio parahaemolyticus inoculated to the sea bass. Direct plate counting (DPC) and PMA-based quantitative loop-mediated isothermal amplification (qLAMP) and qPCR was utilized for discrimination of dead and live bacteria on the designated storage days (1, 3, 7, and 14). The optimum amount of PMA was 50 μM for inhibition of amplification derived from dead cells in spiked samples. The number of live V. parahaemolyticus was detectable at the end of the 14. day using PMA-qLAMP and PMA-qPCR at all the temperatures. On the 7th day, culturability has lost at any of the storage temperatures and DPCs at -18 °C and -45 °C revealed a difference of about 1 log10 CFU/ml between 1st and 3rd days. The same difference was also observed in PMA-qLAMP and PMA-qPCR on the same days (0.59-0.95 log10 CFU/ml). Subzero temperatures have the highest rate of viability while causing the fastest decrease in culturability in sample groups as a result of the higher level of transition to VBNC state. qLAMP and qPCR methods in the PMA-treated and nontreated groups on the storage days at all temperatures gave similar results (p > 0.05).
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Affiliation(s)
- A Ezgi Telli
- Department of Food Hygiene and Technology, Faculty of Veterinary Medicine, Selcuk University, Konya, Turkey.
| | - Yusuf Doğruer
- Department of Food Hygiene and Technology, Faculty of Veterinary Medicine, Selcuk University, Konya, Turkey
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40
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Salas-Massó N, Linh QT, Chin WH, Wolff A, Andree KB, Furones MD, Figueras MJ, Bang DD. The Use of a DNA-Intercalating Dye for Quantitative Detection of Viable Arcobacter spp. Cells (v-qPCR) in Shellfish. Front Microbiol 2019; 10:368. [PMID: 30873146 PMCID: PMC6403187 DOI: 10.3389/fmicb.2019.00368] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Accepted: 02/12/2019] [Indexed: 11/13/2022] Open
Abstract
The genus Arcobacter (Vandamme et al., 1991), comprised of Campylobacter-related species, are considered zoonotic emergent pathogens. The presence of Arcobacter in food products like shellfish, has an elevated incidence worldwide. In this study, we developed a specific viable quantitative PCR (v-qPCR), using the dye propidium monoazide (PMA), for quantification of the viable Arcobacter spp. cells in raw oysters and mussels. The high selectivity of primers was demonstrated by using purified DNA from 38 different species, 20 of them from the genus Arcobacter. The optimization of PMA concentration showed that 20 μM was considered as an optimal concentration that inhibits the signal from dead cells at different concentrations (OD550 from 0.2 to 0.8) and at different ratios of live: dead cells (50:50 and 90:10). The v-qPCR results from shellfish samples were compared with those obtained in parallel using several culture isolation approaches (i.e., direct plating on marine and blood agar and by post-enrichment culturing in both media). The enrichment was performed in parallel in Arcobacter-CAT broth with and without adding NaCl. Additionally, the v-qPCR results were compared to those obtained with traditional quantitative (qPCR). The v-qPCR and the qPCR resulted in c.a. 94% of positive detection of Arcobacter vs. 41% obtained by culture approaches. When examining the reduction effect resulting from the use of v-qPCR, samples pre-enriched in Arcobacter-CAT broth supplemented with 2.5% NaCl showed a higher reduction (3.27 log copies) than that of samples obtained directly and those pre-enriched in Arcobacter-CAT broth isolation (1.05 and 1.04). When the v-qPCR was applied to detect arcobacter from real shellfish samples, 15/17 samples tested positive for viable Arcobacter with 3.41 to 8.70 log copies 1g-1. This study offers a new tool for Arcobacter surveillance in seafood.
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Affiliation(s)
- Nuria Salas-Massó
- Unitat de Microbiologia, Departament de Ciènces Médiques Bàsiques, Facultat de Medicina i Ciències de la Salut, Institut d’Investigació Sanitària Pere Virgili, Universitat Rovira i Virgili, Reus, Spain
- IRTA-Sant Carles de la Ràpita, Sant Carles de la Ràpita, Spain
| | - Quyen Than Linh
- Department of Bioengineering and Biomedicine, Technical University of Denmark, Lyngby, Denmark
| | | | - Anders Wolff
- Department of Bioengineering and Biomedicine, Technical University of Denmark, Lyngby, Denmark
| | - Karl B. Andree
- IRTA-Sant Carles de la Ràpita, Sant Carles de la Ràpita, Spain
| | | | - María José Figueras
- Unitat de Microbiologia, Departament de Ciènces Médiques Bàsiques, Facultat de Medicina i Ciències de la Salut, Institut d’Investigació Sanitària Pere Virgili, Universitat Rovira i Virgili, Reus, Spain
| | - Dang Duong Bang
- Division of Microbiology, National Food Institute, Technical University of Denmark, Lyngby, Denmark
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Ricke SC, Feye KM, Chaney WE, Shi Z, Pavlidis H, Yang Y. Developments in Rapid Detection Methods for the Detection of Foodborne Campylobacter in the United States. Front Microbiol 2019; 9:3280. [PMID: 30728816 PMCID: PMC6351486 DOI: 10.3389/fmicb.2018.03280] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Accepted: 12/17/2018] [Indexed: 12/27/2022] Open
Abstract
The accurate and rapid detection of Campylobacter spp. is critical for optimal surveillance throughout poultry processing in the United States. The further development of highly specific and sensitive assays to detect Campylobacter in poultry matrices has tremendous utility and potential for aiding the reduction of foodborne illness. The introduction and development of molecular methods such as polymerase chain reaction (PCR) have enhanced the diagnostic capabilities of the food industry to identify the presence of foodborne pathogens throughout poultry production. Further innovations in various methodologies, such as immune-based typing and detection as well as high throughput analyses, will provide important epidemiological data such as the identification of unique or region-specific Campylobacter. Comparable to traditional microbiology and enrichment techniques, molecular techniques/methods have the potential to have improved sensitivity and specificity, as well as speed of data acquisition. This review will focus on the development and application of rapid molecular methods for identifying and quantifying Campylobacter in U.S. poultry and the emergence of novel methods that are faster and more precise than traditional microbiological techniques.
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Affiliation(s)
- Steven C. Ricke
- Department of Food Science, Center of Food Safety, University of Arkansas, Fayetteville, AR, United States
| | - Kristina M. Feye
- Department of Food Science, Center of Food Safety, University of Arkansas, Fayetteville, AR, United States
| | | | - Zhaohao Shi
- Department of Food Science, Center of Food Safety, University of Arkansas, Fayetteville, AR, United States
| | | | - Yichao Yang
- Department of Poultry Science, University of Arkansas, Fayetteville, AR, United States
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Pacholewicz E, Buhler C, Wulsten IF, Kraushaar B, Luu HQ, Iwobi AN, Huber I, Stingl K. Internal sample process control improves cultivation-independent quantification of thermotolerant Campylobacter. Food Microbiol 2018; 78:53-61. [PMID: 30497608 DOI: 10.1016/j.fm.2018.09.017] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 08/30/2018] [Accepted: 09/26/2018] [Indexed: 11/26/2022]
Abstract
Quantification of Campylobacter is challenging and one major reason is the fact that bacteria lose cultivability due to cold or oxygen stress during storage at retail. Alternative live/dead discriminatory qPCR currently lacks standardization and might overestimate live cells in the presence of dead cells. In this study an internal sample process control (ISPC) was developed. The ISPC consists of a specified number of peroxide-killed C. sputorum cells to be added to each sample in order to monitor (i) the level of reduction of the signal from dead cells and (ii) DNA losses during sample processing. A species-specific fragment of the 16S rRNA gene of C. sputorum was selected as real-time PCR target, based on its similar size and gene copy number compared to the C. jejuni/coli/lari target and confirmed in an exclusivity study. Extension of the amplification oligonucleotides for the target of thermotolerant Campylobacter improved real-time PCR efficiency, rendering the method suitable for quantification according to international standards. Concordant PCR signal variation of both C. jejuni and C. sputorum targets in co-inoculated chicken rinses verified the suitability of the ISPC. This provides a crucial step towards implementation of cultivation-independent quantification for improved food safety of fastidious bacteria.
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Affiliation(s)
- Ewa Pacholewicz
- German Federal Institute for Risk Assessment (BfR), Department of Biological Safety, National Reference Laboratory for Campylobacter, Berlin, Germany
| | - Christiane Buhler
- German Federal Institute for Risk Assessment (BfR), Department of Biological Safety, National Reference Laboratory for Campylobacter, Berlin, Germany
| | - Imke F Wulsten
- German Federal Institute for Risk Assessment (BfR), Department of Biological Safety, National Reference Laboratory for Campylobacter, Berlin, Germany
| | - Britta Kraushaar
- German Federal Institute for Risk Assessment (BfR), Department of Biological Safety, National Reference Laboratory for Campylobacter, Berlin, Germany
| | - Huong Quynh Luu
- National Institute of Veterinary Research (NIVR), Hanoi, Viet Nam
| | - Azuka N Iwobi
- Bavarian Health and Food Safety Authority (LGL), Oberschleissheim, Germany
| | - Ingrid Huber
- Bavarian Health and Food Safety Authority (LGL), Oberschleissheim, Germany
| | - Kerstin Stingl
- German Federal Institute for Risk Assessment (BfR), Department of Biological Safety, National Reference Laboratory for Campylobacter, Berlin, Germany.
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43
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Castro AGSA, Dorneles EMS, Santos ELS, Alves TM, Silva GR, Figueiredo TC, Assis DCS, Lage AP, Cançado SV. Viability of Campylobacter spp. in frozen and chilled broiler carcasses according to real-time PCR with propidium monoazide pretreatment. Poult Sci 2018; 97:1706-1711. [PMID: 29471351 DOI: 10.3382/ps/pey020] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Accepted: 01/08/2018] [Indexed: 11/20/2022] Open
Abstract
The aim of this study was to evaluate the viability of Campylobacter spp. in frozen and chilled broiler carcasses using real-time PCR with propidium monoazide (PMA) pretreatment. Sixty broiler carcasses were collected: 30 frozen and 30 chilled. Each carcass was submitted to 2 real-time PCR protocols to detect and quantify Campylobacter spp.: one using pretreatment with PMA, which blocks the amplification of DNA from dead bacteria, and the other without PMA. The results showed that PMA-pretreated carcasses, either frozen or chilled, had a lower positivity rate compared to untreated samples (P < 0.001). Regarding storage temperatures, PMA-pretreated frozen carcasses that tested positive were in a lesser number than chilled carcasses (P < 0.05). However, the quantification of total and live bacteria in PMA-pretreated frozen carcasses that tested positive showed no significant difference compared to chilled carcasses. It was concluded that the real-time PCR with PMA pretreatment was a sensitive method for evaluating the viability of Campylobacter spp. in broiler carcasses. Chilled broiler carcasses would represent greater hazard to public health concerning Campylobacter transmission.
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Affiliation(s)
- Andréa G S A Castro
- Departamento de Tecnologia e Inspeção de Produtos de Origem Animal, Escola de Veterinária, Universidade Federal de Minas Gerais, Av. Antônio Carlos 6627, Caixa Postal 567, 30123-970, Belo Horizonte, MG, Brazil
| | - Elaine M S Dorneles
- Departamento de Medicina Veterinária, Universidade Federal de Lavras, Av. Dr. Sylvio Menicucci 1001, Caixa Postal 3037, 37200-000, Lavras, MG, Brazil
| | - Ethiene L S Santos
- Departamento de Tecnologia e Inspeção de Produtos de Origem Animal, Escola de Veterinária, Universidade Federal de Minas Gerais, Av. Antônio Carlos 6627, Caixa Postal 567, 30123-970, Belo Horizonte, MG, Brazil
| | - Telma M Alves
- Departamento de Medicina Veterinária Preventiva, Escola de Veterinária, Universidade Federal de Minas Gerais, Av. Antônio Carlos 6627, Caixa Postal 567, 30123-970, Belo Horizonte, MG, Brazil
| | - Guilherme R Silva
- Departamento de Tecnologia e Inspeção de Produtos de Origem Animal, Escola de Veterinária, Universidade Federal de Minas Gerais, Av. Antônio Carlos 6627, Caixa Postal 567, 30123-970, Belo Horizonte, MG, Brazil
| | - Tadeu C Figueiredo
- Departamento de Tecnologia e Inspeção de Produtos de Origem Animal, Escola de Veterinária, Universidade Federal de Minas Gerais, Av. Antônio Carlos 6627, Caixa Postal 567, 30123-970, Belo Horizonte, MG, Brazil
| | - Débora C S Assis
- Departamento de Tecnologia e Inspeção de Produtos de Origem Animal, Escola de Veterinária, Universidade Federal de Minas Gerais, Av. Antônio Carlos 6627, Caixa Postal 567, 30123-970, Belo Horizonte, MG, Brazil
| | - Andrey P Lage
- Departamento de Medicina Veterinária Preventiva, Escola de Veterinária, Universidade Federal de Minas Gerais, Av. Antônio Carlos 6627, Caixa Postal 567, 30123-970, Belo Horizonte, MG, Brazil
| | - Silvana V Cançado
- Departamento de Tecnologia e Inspeção de Produtos de Origem Animal, Escola de Veterinária, Universidade Federal de Minas Gerais, Av. Antônio Carlos 6627, Caixa Postal 567, 30123-970, Belo Horizonte, MG, Brazil
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Yeluri Jonnala BR, McSweeney PLH, Sheehan JJ, Cotter PD. Sequencing of the Cheese Microbiome and Its Relevance to Industry. Front Microbiol 2018; 9:1020. [PMID: 29875744 PMCID: PMC5974213 DOI: 10.3389/fmicb.2018.01020] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Accepted: 04/30/2018] [Indexed: 12/28/2022] Open
Abstract
The microbiota of cheese plays a key role in determining its organoleptic and other physico-chemical properties. It is essential to understand the various contributions, positive or negative, of these microbial components in order to promote the growth of desirable taxa and, thus, characteristics. The recent application of high throughput DNA sequencing (HTS) facilitates an even more accurate identification of these microbes, and their functional properties, and has the potential to reveal those microbes, and associated pathways, responsible for favorable or unfavorable characteristics. This technology also facilitates a detailed analysis of the composition and functional potential of the microbiota of milk, curd, whey, mixed starters, processing environments, and how these contribute to the final cheese microbiota, and associated characteristics. Ultimately, this information can be harnessed by producers to optimize the quality, safety, and commercial value of their products. In this review we highlight a number of key studies in which HTS was employed to study the cheese microbiota, and pay particular attention to those of greatest relevance to industry.
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Affiliation(s)
- Bhagya R Yeluri Jonnala
- Food and Nutrition Deptartment, University College Cork, Cork, Ireland.,Teagasc Food Research Centre, Fermoy, Ireland
| | | | | | - Paul D Cotter
- Teagasc Food Research Centre, Fermoy, Ireland.,APC Microbiome Ireland, Cork, Ireland
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45
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Han S, Jiang N, Lv Q, Kan Y, Hao J, Li J, Luo L. Detection of Clavibacter michiganensis subsp. michiganensis in viable but nonculturable state from tomato seed using improved qPCR. PLoS One 2018; 13:e0196525. [PMID: 29723290 PMCID: PMC5933903 DOI: 10.1371/journal.pone.0196525] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Accepted: 04/13/2018] [Indexed: 12/02/2022] Open
Abstract
Clavibacter michiganensis subsp. michiganensis (Cmm) is a seed-borne pathogen that causes bacterial canker disease of tomato. Cmm is typically detected in tomato seeds using quantitative real-time polymerase chain reaction (qPCR) combined with culture-based isolation. The viable but nonculturable (VBNC) state of Cmm may result in the underestimation or false negative detection of the pathogen. In the present study, propidium monoazide (PMA) and its improved structure PMAxx were used to pretreat Cmm prior to DNA extraction, followed by qPCR. Both PMA and PMAxx could bind to the chromosomal DNA of dead bacterial cells and therefore block DNA amplification by PCR. This effect, however, does not occur in living bacterial cells, as the chemicals cannot penetrate through the undamaged cell membrane. Both viable and dead Cmm cells were treated with PMA and PMAxx at various concentrations. With this treatment, the range of the cell population was determined for effective detection. PMAxx showed a better discrimination effect than PMA on the viable and dead cells of Cmm and was therefore used throughout the present study. VBNC cells of Cmm (108 CFU mL-1) was induced by 50 μM copper sulfate, which was detected at different sampling times up to a month by using both PMAxx-qPCR and flow cytometry assays. The optimal PMAxx concentration was 20 μM for detecting membrane-intact Cmm cells. High specificity and sensitivity were obtained at Cmm concentrations ranging from 103 to 107 CFU mL-1. The accurate and robust results of PMAxx-qPCR were confirmed by flow cytometry method to detect viable Cmm cells. Furthermore, the PMAxx-qPCR assay was successfully used in detecting VBNC Cmm cells in tomato seeds with as few as 10 seeds per set.
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Affiliation(s)
- Sining Han
- Department of Plant Pathology and MOA Key Lab of Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing, P. R. China
- Beijing Key Laboratory of Seed Disease Testing and Control (BKL-SDTC), China Agricultural University, Beijing, P. R. China
| | - Na Jiang
- Department of Plant Pathology and MOA Key Lab of Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing, P. R. China
- Beijing Key Laboratory of Seed Disease Testing and Control (BKL-SDTC), China Agricultural University, Beijing, P. R. China
| | - Qingyang Lv
- Department of Plant Pathology and MOA Key Lab of Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing, P. R. China
- Beijing Key Laboratory of Seed Disease Testing and Control (BKL-SDTC), China Agricultural University, Beijing, P. R. China
| | - Yumin Kan
- Department of Plant Pathology and MOA Key Lab of Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing, P. R. China
- Beijing Key Laboratory of Seed Disease Testing and Control (BKL-SDTC), China Agricultural University, Beijing, P. R. China
| | - Jianjun Hao
- School of Food and Agriculture, The University of Maine, Orono, Maine, United States of America
| | - Jianqiang Li
- Department of Plant Pathology and MOA Key Lab of Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing, P. R. China
- Beijing Key Laboratory of Seed Disease Testing and Control (BKL-SDTC), China Agricultural University, Beijing, P. R. China
| | - Laixin Luo
- Department of Plant Pathology and MOA Key Lab of Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing, P. R. China
- Beijing Key Laboratory of Seed Disease Testing and Control (BKL-SDTC), China Agricultural University, Beijing, P. R. China
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46
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Growth delay analysis of heat-injured Salmonella Enteritidis in ground beef by real-time PCR. Lebensm Wiss Technol 2018. [DOI: 10.1016/j.lwt.2017.12.066] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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47
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Quantification and Discrimination of Viable and Dead Escherichia coli O157:H7 Cells from Chicken Without Enrichment by Ethidium Bromide Monoazide Real-time Loop-Mediated Isothermal Amplification. FOOD ANAL METHOD 2017. [DOI: 10.1007/s12161-017-1092-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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48
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Study and Understanding Behavior of Alginate-Inulin Synbiotics Beads for Protection and Delivery of Antimicrobial-Producing Probiotics in Colonic Simulated Conditions. Probiotics Antimicrob Proteins 2017; 10:157-167. [DOI: 10.1007/s12602-017-9355-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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49
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Jeong MI, Park SY, Ha SD. Thermal inactivation of human norovirus on spinach using propidium or ethidium monoazide combined with real-time quantitative reverse transcription-polymerase chain reaction. Food Control 2017. [DOI: 10.1016/j.foodcont.2017.02.026] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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50
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Frasao BDS, Marin VA, Conte-Junior CA. Molecular Detection, Typing, and Quantification ofCampylobacterspp. in Foods of Animal Origin. Compr Rev Food Sci Food Saf 2017; 16:721-734. [DOI: 10.1111/1541-4337.12274] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2017] [Revised: 05/11/2017] [Accepted: 05/17/2017] [Indexed: 01/28/2023]
Affiliation(s)
- Beatriz da Silva Frasao
- Dept. of Food Technology; Fluminense Federal Univ. (UFF) 24.230-340; Niteroi RJ Brazil
- Dept. of Epidemiology and Public Health; Federal Rural Univ. of Rio de Janeiro (UFRRJ), 23.897-000; Seropédica RJ Brazil
| | - Victor Augustus Marin
- Dept. of Food Science; Federal Univ. of the State of Rio de Janeiro (UNIRIO), 22.290-255; Rio de Janeiro RJ Brazil
| | - Carlos Adam Conte-Junior
- Dept. of Food Technology; Fluminense Federal Univ. (UFF) 24.230-340; Niteroi RJ Brazil
- Natl. Inst. for Health Quality Control; Oswaldo Cruz Foundation (FIOCRUZ), 21.040-900; Rio de Janeiro RJ Brazil
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