Escherichia coli (E. coli) can be associated with food contamination incidents and frequently causes serious food poisoning in humans. Detection and enumeration of E. coli in food matrices is crucial regarding food safety issues. Most Probable Number (MPN) assay for the enumeration of E. coli is widely used in laboratories. A limitation of the conventional reference MPN method is the long time required to obtain definitive results, which often sequels dissatisfaction among the customers. The aim of the current research was to mitigate the problem by the integration of a credible and rapid tool for the confirmatory identification of E. coli in MPN assay instead of biochemical tests. Real-time PCR and/or MALDI TOF MS were considered better candidates for so. The experiment was conducted in three sample matrices (beef, chicken, milk) and each was spiked with target E. coli (ATCC 25922) at low (47.7±4.5 CFU/g), intermediate (103.0±5.0 CFU/g), and high (204.7±2.5 CFU/g) doses. The mean E. coli counts by MPN method in low, intermediate, and high-level contaminated beef were 53.7±4.0, 99.3±9.2, and 216±5.8/g respectively. Those in chicken were 53.3±4.6, 110.0±0.0, and 203.3±20.8/g; and in milk 56.0±0.0, 104.7±9.2, and 213.3±5.8/ml respectively. Real-time PCR and MALDI TOF MS did not differ significantly (p=0.199) with biochemical tests in resulting MPN of E. coli in sample matrices. The method was found very linear within the contamination range with high R-squared values (≥ 0.99) in all three sample matrices. The mean assay time when employed biochemical tests, real-time PCR and MALDI TOF MS were 121.3±6.3, 77.4±6.3, and 74.2±6.1 hours respectively. Both real-time PCR and MALDI TOF MS significantly (p=0.000) reduced the assay time compared to that by biochemical tests. Significant (p=0.003) difference was also found between MPN assay times required by real-time PCR and MALDI TOF MS methods. Considering the research findings, MALDI TOF MS is recommended for integration in MPN assay for E. coli.
| Published in | International Journal of Microbiology and Biotechnology (Volume 7, Issue 2) |
| DOI | 10.11648/j.ijmb.20220702.19 |
| Page(s) | 106-114 |
| Creative Commons |
This is an Open Access article, distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution and reproduction in any medium or format, provided the original work is properly cited. |
| Copyright |
Copyright © The Author(s), 2022. Published by Science Publishing Group |
MPN, Escherichia coli, PCR, MALDI TOF MS
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APA Style
Md. Al-Amin, Md. Mostofa Kamal. (2022). Integration of MALDI TOF MS in the Most Probable Number Method for Enumeration of Escherichia coli Significantly Reduces the Assay Time. International Journal of Microbiology and Biotechnology, 7(2), 106-114. https://doi.org/10.11648/j.ijmb.20220702.19
ACS Style
Md. Al-Amin; Md. Mostofa Kamal. Integration of MALDI TOF MS in the Most Probable Number Method for Enumeration of Escherichia coli Significantly Reduces the Assay Time. Int. J. Microbiol. Biotechnol. 2022, 7(2), 106-114. doi: 10.11648/j.ijmb.20220702.19
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Download@article{10.11648/j.ijmb.20220702.19,
author = {Md. Al-Amin and Md. Mostofa Kamal},
title = {Integration of MALDI TOF MS in the Most Probable Number Method for Enumeration of Escherichia coli Significantly Reduces the Assay Time},
journal = {International Journal of Microbiology and Biotechnology},
volume = {7},
number = {2},
pages = {106-114},
doi = {10.11648/j.ijmb.20220702.19},
url = {https://doi.org/10.11648/j.ijmb.20220702.19},
eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.ijmb.20220702.19},
abstract = {Escherichia coli (E. coli) can be associated with food contamination incidents and frequently causes serious food poisoning in humans. Detection and enumeration of E. coli in food matrices is crucial regarding food safety issues. Most Probable Number (MPN) assay for the enumeration of E. coli is widely used in laboratories. A limitation of the conventional reference MPN method is the long time required to obtain definitive results, which often sequels dissatisfaction among the customers. The aim of the current research was to mitigate the problem by the integration of a credible and rapid tool for the confirmatory identification of E. coli in MPN assay instead of biochemical tests. Real-time PCR and/or MALDI TOF MS were considered better candidates for so. The experiment was conducted in three sample matrices (beef, chicken, milk) and each was spiked with target E. coli (ATCC 25922) at low (47.7±4.5 CFU/g), intermediate (103.0±5.0 CFU/g), and high (204.7±2.5 CFU/g) doses. The mean E. coli counts by MPN method in low, intermediate, and high-level contaminated beef were 53.7±4.0, 99.3±9.2, and 216±5.8/g respectively. Those in chicken were 53.3±4.6, 110.0±0.0, and 203.3±20.8/g; and in milk 56.0±0.0, 104.7±9.2, and 213.3±5.8/ml respectively. Real-time PCR and MALDI TOF MS did not differ significantly (p=0.199) with biochemical tests in resulting MPN of E. coli in sample matrices. The method was found very linear within the contamination range with high R-squared values (≥ 0.99) in all three sample matrices. The mean assay time when employed biochemical tests, real-time PCR and MALDI TOF MS were 121.3±6.3, 77.4±6.3, and 74.2±6.1 hours respectively. Both real-time PCR and MALDI TOF MS significantly (p=0.000) reduced the assay time compared to that by biochemical tests. Significant (p=0.003) difference was also found between MPN assay times required by real-time PCR and MALDI TOF MS methods. Considering the research findings, MALDI TOF MS is recommended for integration in MPN assay for E. coli.},
year = {2022}
}
TY - JOUR T1 - Integration of MALDI TOF MS in the Most Probable Number Method for Enumeration of Escherichia coli Significantly Reduces the Assay Time AU - Md. Al-Amin AU - Md. Mostofa Kamal Y1 - 2022/06/30 PY - 2022 N1 - https://doi.org/10.11648/j.ijmb.20220702.19 DO - 10.11648/j.ijmb.20220702.19 T2 - International Journal of Microbiology and Biotechnology JF - International Journal of Microbiology and Biotechnology JO - International Journal of Microbiology and Biotechnology SP - 106 EP - 114 PB - Science Publishing Group SN - 2578-9686 UR - https://doi.org/10.11648/j.ijmb.20220702.19 AB - Escherichia coli (E. coli) can be associated with food contamination incidents and frequently causes serious food poisoning in humans. Detection and enumeration of E. coli in food matrices is crucial regarding food safety issues. Most Probable Number (MPN) assay for the enumeration of E. coli is widely used in laboratories. A limitation of the conventional reference MPN method is the long time required to obtain definitive results, which often sequels dissatisfaction among the customers. The aim of the current research was to mitigate the problem by the integration of a credible and rapid tool for the confirmatory identification of E. coli in MPN assay instead of biochemical tests. Real-time PCR and/or MALDI TOF MS were considered better candidates for so. The experiment was conducted in three sample matrices (beef, chicken, milk) and each was spiked with target E. coli (ATCC 25922) at low (47.7±4.5 CFU/g), intermediate (103.0±5.0 CFU/g), and high (204.7±2.5 CFU/g) doses. The mean E. coli counts by MPN method in low, intermediate, and high-level contaminated beef were 53.7±4.0, 99.3±9.2, and 216±5.8/g respectively. Those in chicken were 53.3±4.6, 110.0±0.0, and 203.3±20.8/g; and in milk 56.0±0.0, 104.7±9.2, and 213.3±5.8/ml respectively. Real-time PCR and MALDI TOF MS did not differ significantly (p=0.199) with biochemical tests in resulting MPN of E. coli in sample matrices. The method was found very linear within the contamination range with high R-squared values (≥ 0.99) in all three sample matrices. The mean assay time when employed biochemical tests, real-time PCR and MALDI TOF MS were 121.3±6.3, 77.4±6.3, and 74.2±6.1 hours respectively. Both real-time PCR and MALDI TOF MS significantly (p=0.000) reduced the assay time compared to that by biochemical tests. Significant (p=0.003) difference was also found between MPN assay times required by real-time PCR and MALDI TOF MS methods. Considering the research findings, MALDI TOF MS is recommended for integration in MPN assay for E. coli. VL - 7 IS - 2 ER -
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