Detection of Salmonella enterica in meat in less than 5 hours by a low-cost and non-complex sample preparation method

Mette Sofie Rousing Fachmann, Charlotta Löfström, Jeffrey Hoorfar, F. Hansen, Julia Christensen, S. Mansdal, Mathilde Hasseldam Josefsen

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Abstract

Salmonella is recognised as one of the most important foodborne bacteria, and has a wide health and socioeconomical impact worldwide. Fresh pork meat is one of the main sources of Salmonella and efficient and fast methods for detection are therefore necessary. Current methods for Salmonella detection in fresh meat usually include >16 h of culture enrichment, in few cases <12 h, thus requiring at least two working shifts. Here, we report a rapid (<5 h) and high throughput method, for screening of Salmonella in samples from fresh pork meat, consisting of a 3-h enrichment in standard buffered peptone water, and a real-time PCR compatible sample preparation method, based on filtration, centrifugation, and enzymatic digestion, followed by fast cycling real-time PCR detection. The method was validated in an un-paired, comparative study against the Nordic Committee on Food Analysis (NMKL) reference culture method 187. Pork meat samples (n=140) were either artificially contaminated with Salmonella at levels: 0, 1-10 and 10-100 CFU/25 g, or naturally contaminated. Cohen's Kappa for degree of agreement between the rapid method and the reference was 0.64 and the relative accuracy, sensitivity and specificity for the rapid method were 81.4, 95.1 and 97.9 %, respectively. The limit of detection (LOD50) was 8.8 CFU/25 g for the rapid method and 7.7 CFU/25 g for the reference method. Implementation of this method will enable faster release of Salmonella low risk meat, providing savings for meat producers, and help contribute to improved food safety. While the cost of analysis and hands-on time of the presented rapid method were comparable to reference culture methods, the fast product release by this method can provide the meat industry with a competitive advantage. Not only will the abattoirs save costs for work hours and cold storage; consumers as well as retailers will also benefit from fresher meat with a longer shelf life. Furthermore, the presented sample preparation might be adjusted for application in detection of other pathogenic bacteria in different sample types.
Original languageEnglish
Article numbere03151-16
JournalAPPLIED AND ENVIRONMENTAL MICROBIOLOGY
Volume83
Issue number5
ISSN0099-2240
DOIs
Publication statusPublished - 2017

Cite this

Fachmann, Mette Sofie Rousing ; Löfström, Charlotta ; Hoorfar, Jeffrey ; Hansen, F. ; Christensen, Julia ; Mansdal, S. ; Josefsen, Mathilde Hasseldam. / Detection of Salmonella enterica in meat in less than 5 hours by a low-cost and non-complex sample preparation method. In: APPLIED AND ENVIRONMENTAL MICROBIOLOGY. 2017 ; Vol. 83, No. 5.
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abstract = "Salmonella is recognised as one of the most important foodborne bacteria, and has a wide health and socioeconomical impact worldwide. Fresh pork meat is one of the main sources of Salmonella and efficient and fast methods for detection are therefore necessary. Current methods for Salmonella detection in fresh meat usually include >16 h of culture enrichment, in few cases <12 h, thus requiring at least two working shifts. Here, we report a rapid (<5 h) and high throughput method, for screening of Salmonella in samples from fresh pork meat, consisting of a 3-h enrichment in standard buffered peptone water, and a real-time PCR compatible sample preparation method, based on filtration, centrifugation, and enzymatic digestion, followed by fast cycling real-time PCR detection. The method was validated in an un-paired, comparative study against the Nordic Committee on Food Analysis (NMKL) reference culture method 187. Pork meat samples (n=140) were either artificially contaminated with Salmonella at levels: 0, 1-10 and 10-100 CFU/25 g, or naturally contaminated. Cohen's Kappa for degree of agreement between the rapid method and the reference was 0.64 and the relative accuracy, sensitivity and specificity for the rapid method were 81.4, 95.1 and 97.9 {\%}, respectively. The limit of detection (LOD50) was 8.8 CFU/25 g for the rapid method and 7.7 CFU/25 g for the reference method. Implementation of this method will enable faster release of Salmonella low risk meat, providing savings for meat producers, and help contribute to improved food safety. While the cost of analysis and hands-on time of the presented rapid method were comparable to reference culture methods, the fast product release by this method can provide the meat industry with a competitive advantage. Not only will the abattoirs save costs for work hours and cold storage; consumers as well as retailers will also benefit from fresher meat with a longer shelf life. Furthermore, the presented sample preparation might be adjusted for application in detection of other pathogenic bacteria in different sample types.",
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Detection of Salmonella enterica in meat in less than 5 hours by a low-cost and non-complex sample preparation method. / Fachmann, Mette Sofie Rousing; Löfström, Charlotta; Hoorfar, Jeffrey; Hansen, F.; Christensen, Julia; Mansdal, S.; Josefsen, Mathilde Hasseldam.

In: APPLIED AND ENVIRONMENTAL MICROBIOLOGY, Vol. 83, No. 5, e03151-16, 2017.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Detection of Salmonella enterica in meat in less than 5 hours by a low-cost and non-complex sample preparation method

AU - Fachmann, Mette Sofie Rousing

AU - Löfström, Charlotta

AU - Hoorfar, Jeffrey

AU - Hansen, F.

AU - Christensen, Julia

AU - Mansdal, S.

AU - Josefsen, Mathilde Hasseldam

PY - 2017

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N2 - Salmonella is recognised as one of the most important foodborne bacteria, and has a wide health and socioeconomical impact worldwide. Fresh pork meat is one of the main sources of Salmonella and efficient and fast methods for detection are therefore necessary. Current methods for Salmonella detection in fresh meat usually include >16 h of culture enrichment, in few cases <12 h, thus requiring at least two working shifts. Here, we report a rapid (<5 h) and high throughput method, for screening of Salmonella in samples from fresh pork meat, consisting of a 3-h enrichment in standard buffered peptone water, and a real-time PCR compatible sample preparation method, based on filtration, centrifugation, and enzymatic digestion, followed by fast cycling real-time PCR detection. The method was validated in an un-paired, comparative study against the Nordic Committee on Food Analysis (NMKL) reference culture method 187. Pork meat samples (n=140) were either artificially contaminated with Salmonella at levels: 0, 1-10 and 10-100 CFU/25 g, or naturally contaminated. Cohen's Kappa for degree of agreement between the rapid method and the reference was 0.64 and the relative accuracy, sensitivity and specificity for the rapid method were 81.4, 95.1 and 97.9 %, respectively. The limit of detection (LOD50) was 8.8 CFU/25 g for the rapid method and 7.7 CFU/25 g for the reference method. Implementation of this method will enable faster release of Salmonella low risk meat, providing savings for meat producers, and help contribute to improved food safety. While the cost of analysis and hands-on time of the presented rapid method were comparable to reference culture methods, the fast product release by this method can provide the meat industry with a competitive advantage. Not only will the abattoirs save costs for work hours and cold storage; consumers as well as retailers will also benefit from fresher meat with a longer shelf life. Furthermore, the presented sample preparation might be adjusted for application in detection of other pathogenic bacteria in different sample types.

AB - Salmonella is recognised as one of the most important foodborne bacteria, and has a wide health and socioeconomical impact worldwide. Fresh pork meat is one of the main sources of Salmonella and efficient and fast methods for detection are therefore necessary. Current methods for Salmonella detection in fresh meat usually include >16 h of culture enrichment, in few cases <12 h, thus requiring at least two working shifts. Here, we report a rapid (<5 h) and high throughput method, for screening of Salmonella in samples from fresh pork meat, consisting of a 3-h enrichment in standard buffered peptone water, and a real-time PCR compatible sample preparation method, based on filtration, centrifugation, and enzymatic digestion, followed by fast cycling real-time PCR detection. The method was validated in an un-paired, comparative study against the Nordic Committee on Food Analysis (NMKL) reference culture method 187. Pork meat samples (n=140) were either artificially contaminated with Salmonella at levels: 0, 1-10 and 10-100 CFU/25 g, or naturally contaminated. Cohen's Kappa for degree of agreement between the rapid method and the reference was 0.64 and the relative accuracy, sensitivity and specificity for the rapid method were 81.4, 95.1 and 97.9 %, respectively. The limit of detection (LOD50) was 8.8 CFU/25 g for the rapid method and 7.7 CFU/25 g for the reference method. Implementation of this method will enable faster release of Salmonella low risk meat, providing savings for meat producers, and help contribute to improved food safety. While the cost of analysis and hands-on time of the presented rapid method were comparable to reference culture methods, the fast product release by this method can provide the meat industry with a competitive advantage. Not only will the abattoirs save costs for work hours and cold storage; consumers as well as retailers will also benefit from fresher meat with a longer shelf life. Furthermore, the presented sample preparation might be adjusted for application in detection of other pathogenic bacteria in different sample types.

U2 - 10.1128/AEM.03151-16

DO - 10.1128/AEM.03151-16

M3 - Journal article

VL - 83

JO - Applied and Environmental Microbiology

JF - Applied and Environmental Microbiology

SN - 0099-2240

IS - 5

M1 - e03151-16

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