Rapid and portable microfluidic chip-based qPCR for quality assurance of commercial seaweeds (lavers) in the supply chain

Lavers, an important type of seaweed rich in health-promoting substances, have seen a surge in global demand. However, their similar morphological characteristics among different species make them vulnerable to food fraud. To address this issue and ensure quality assurance, we developed a portable microfluidic quantitative polymerase chain reaction (qPCR) method to monitor six laver species, comparing its effectiveness with conventional qPCR. Our portable microfluidic qPCR system used a plate-shaped heat block for rapid heat transfer, combined with a microfluidic-based biochip for quick detection. The primers were specifically designed to target the chloroplast genes rbcL and rbcS. Specificity using 17 seaweed species showed no cross-reactivity, and the sensitivity of the assay was 1×10−4 ng. Furthermore, we enhanced the portable microfluidic qPCR for field applications by integrating it with a simple DNA extraction method. To validate the on-site rapid identification of laver species, we evaluated 79 laver samples collected from fish farms in Korea and commercially available laver products. We discovered instances where products were adulterated with cheaper species or replaced with others that resemble them. This method proves to be rapid, sensitive, reliable, and applicable for effectively managing and monitoring lavers in the supply chain.