Rapid and specific detection of mackerels of the genus Scomber using loop-mediated isothermal amplification (LAMP)

This study presents a novel method for the rapid and precise detection of mackerels belonging to the genus Scomber, which are prevalent in the Japanese market and are subject to labeling regulations owing to allergenic concerns. We developed loop-mediated isothermal amplification (LAMP) methods targeting the ribosomal DNA sequences of four Scomber species: S. japonicus, S. australasicus, S. scombrus, and S. colias. By incorporating hydroxynaphthol blue for colorimetric detection, our method enables visual inspection of results, eliminating the need for complex instruments. Optimization of LAMP conditions and verification of specificity demonstrated reliable detection of Scomber DNA with a minimum detection limit of 1–100 pg, depending on the Scomber species, and enabling efficient detection within 30–60 min using a simple incubator. No cross-amplification occurred among closely related species. Additionally, we successfully detected Scomber DNA in processed foods, demonstrating the usefulness and practicality of our LAMP methods. Despite relatively lower sensitivity compared with real-time polymerase chain reaction (PCR), our LAMP methods offer advantages in simplicity, rapidity, and ease of use, making the methods suitable for broader application beyond specialized laboratories. Thus, our LAMP methods provide a practical solution for monitoring food labeling compliance, thereby enhancing consumer confidence and regulatory efficiency.