In this study, (open access) an extraction-free loop-mediated isothermal amplification (LAMP) assay with a visual colorimetric readout was developed for rapid and on-site identification of pork. The reaction conditions were first optimized using purified DNA to minimize matrix interference, during which a COI-targeting primer set was selected and analytical sensitivity determined.
For direct tissue analysis, a simple toothpick sampling approach was introduced. A sterile bamboo toothpick was inserted into the tissue sample and gently probed five times to collect material. The toothpick tip was then inserted vertically into a pre-aliquoted LAMP master mix and rotated for 10 s to release sample contents.
Tris-HCl buffer (1.5 M, pH 8.8) was incorporated to counteract matrix acidity and stabilize color development of the pH-sensitive indicator. This enabled clear color differentiation under daylight without the need for UV illumination.
The authors report that, using this toothpick sampling method, pork adulteration as low as 0.05% (w/w) was detected within 20 min requiring no specialized instrumentation. Validation with 20 commercial meat products demonstrated complete agreement between LAMP results, qPCR, and Sanger sequencing, confirming the robustness and practical suitability of this assay for field authentication of pork adulteration.
For an explanation of LAMP, see our Analytical Explainers pages.
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