The development of loop-mediated isothermal amplification (LAMP) assays for the rapid authentication of five forbidden vegetables in strict vegetarian diets

Abstract

Plant-based food ingredients such as garlic, Chinese leek, Chinese onion, green onion and onion are widely used in many cuisines around the world. However, these ingredients known as the “five forbidden vegetables” (FFVs) are not allowed in some vegetarian diets. In this study, a loop-mediated isothermal amplification (LAMP) assay was developed for the detection of FFVs using five respective LAMP primer sets. The specific primers targeted the ITS1-5.8S-ITS2 nuclear ribosomal DNA sequence regions among the five vegetables. The results demonstrated that the identification of FFVs using the newly developed LAMP assay is more sensitive than the traditional PCR method. Using pepper, basil, parsley, chili and ginger as references, established LAMP primer sets showed high specificity for the identification of the FFV species. Moreover, when FFVs were mixed with other plant ingredients at different ratios (100:0, 50:50, 20:80, 10:90, 5:95, 2:98, and 1:99), no cross-reactivity was evident using LAMP. Finally, genomic DNAs extracted from boiled and steamed FFVs in processed foods were used as templates; the performance of the LAMP reaction was not influenced using validated LAMP primers. Not only can FFV ingredients be identified but commercial foods containing FFVs can also be authenticated. This LAMP method will be useful for the authentication of FFVs in practical food markets in the future.

Specific, sensitive and rapid Curcuma longa turmeric powder authentication in commercial food using loop-mediated isothermal nucleic acid amplification

“…Loop-mediated isothermal amplification (LAMP) is a well-developed DNA amplification method that has been widely used for the authentication of various bioresources, such as bacteria, viruses, animals or plants ( Notomi et al, 2000 , Huang et al, 2010 , Chen et al, 2015 , Lee et al, 2017 , Lee et al, 2019 ). Theoretically, at least four LAMP primers, including two outer primers (denoted by F3 and B3) and two inner primers (denoted by FIP and BIP), were needed to perform the LAMP reaction.…”

“…Only 40–60 mins without any temperature change is required for running the LAMP reaction. These is very convenient for developing a LAMP-based point of care testing (POCT) method for biomaterial authentication ( Notomi et al, 2000 , Huang et al, 2010 , Chen et al, 2015 , Lee et al, 2017 , Lee et al, 2019 ).…”

A Loop-mediated Isothermal Amplification (LAMP) Assay for Rapid Identification of <em>Bemisia tabaci</em>

“…A candidate method is the loop-mediated isothermal DNA amplification (LAMP) technology that has recently been shown to be a suitable technology for the identification of plant pathogens 11 12 13 . LAMP is highly specific because the method uses at least two primer pairs recognizing six distinct DNA target sequences 14 . Due to the DNA strand displacement activity of the Bst DNA polymerase, LAMP reactions are performed under isothermal conditions 14 .…”

“…LAMP is highly specific because the method uses at least two primer pairs recognizing six distinct DNA target sequences 14 . Due to the DNA strand displacement activity of the Bst DNA polymerase, LAMP reactions are performed under isothermal conditions 14 . Hence, in contrast to conventional polymerase chain reaction (PCR)-based assays there is no need for a thermal cycler 13 14 .…”

“…Due to the DNA strand displacement activity of the Bst DNA polymerase, LAMP reactions are performed under isothermal conditions 14 . Hence, in contrast to conventional polymerase chain reaction (PCR)-based assays there is no need for a thermal cycler 13 14 . Another advantage over PCR-based assays is its resilience against potential inhibitors in the DNA extract, circumventing the need for a DNA purification step 13 .…”