Loop-Mediated Isothermal Amplification Assays for the Rapid Identification of Duck-Derived Ingredients in Adulterated Meat

Abstract

Meat adulteration is a growing concern in the marketplace today. To protect consumer rights and prevent unfair competition, it is essential to use an efficient assay to identify rapidly the species of meat being sold. In this context, a loop-mediated isothermal amplification (LAMP) assay coupled with a lateral flow dipstick (LFD) or hydroxynaphthol blue dye (HNB) was developed for the detection of duck genes in meat products. The LAMP-LFD and LAMP-HNB assays were performed at 65 °C for 30 min, with no cross-reactivity against four other species of meat. Sensitivity evaluation showed that the two assays can detect 3 pg of duck DNA per reaction, which is 10 times higher than that of the real-time quantitative polymerase chain reaction (qPCR). Through testing the experimental adulteration models, which were prepared by mixing duck meat with beef at different concentrations (0.01 to 10%), the detection limits of the two assays were confirmed as 0.1% duck meat. Combining the simple DNA extraction assay and the LAMP-LFD or LAMP-HNB assay, adulteration with only 1 mg duck meat can be identified within 40 min. The LAMP-LFD and LAMP-HNB assays are simple and highly sensitive, which provide valuable tools for the identification of duck gene from adulterated meat. The simple DNA extraction assay further enables our LAMP assays to be applicable in the field.