Research articles
ScienceAsia (): 365-370 |doi:
10.2306/scienceasia1513-1874...365
Rapid and sensitive enumeration of total coliforms and
Escherichia coli in water and foods by
most-probable-number loop-mediated isothermal
amplification (MPN-LAMP) method
Chonnikan Tongphroma, Sutima Preeprema, Mitsuaki Nishibushib, Varaporn Vuddhakula,
Pimonsri Mittraparp-arthorna,*
ABSTRACT: Total coliforms and Escherichia coli are bacterial indicators used to assess the microbiological qualities
of water and foods. In this study, we developed a most-probable-number loop-mediated isothermal amplification
(most probable number (MPN-LAMP)) method for the enumeration of total coliforms and E. coli in drinking water
and vegetables. The LAMP primers were designed based on lacZ (lacZ-LAMP) and uidA (uidA-LAMP) genes for the
detection of total coliforms and E. coli, respectively. In pure culture, the lacZ-LAMP and the uidA-LAMP were able to
detect all of the 37 coliforms and 30 E. coli strains, respectively. In the artificially contaminated drinking water and
vegetables, the combination of MPN and LAMP techniques (MPN-LAMP) was able to detect E. coli at 1 colony-forming
unit (CFU)/100 ml and 5 CFU/g, respectively. From analysis of 33 drinking water and 46 vegetable samples, the total
coliform detection obtained by the MPN-LAMP method was in agreement with the MPN detection technique. However,
MPN-LAMP was more sensitive than the MPN technique for E. coli detection. Our findings revealed that the MPN-LAMP
assay was more rapid and highly sensitive than MPN method. Thus this method could be considered for detection and
enumeration of total coliforms and E. coli in the food industry
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a |
Department of Microbiology, Faculty of Science, Prince of Songkla University, Hat Yai,
Songkhla 90110 Thailand |
b |
Division of Human-Nature Dynamics, Centre for Southeast Asian Studies, Kyoto University, Sakyo-ku,
Kyoto 606-8501 Japan |
* Corresponding author, E-mail: pimonsri.m@psu.ac.th
Received 6 Jul 2018, Accepted 1 Oct 2018
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