Point-of-care suitable identification of the adulterants Carthamus tinctorius and Curcuma longa in Crocus sativus based on loop-mediated isothermal amplification (LAMP) and lateral-flow-assay (LFA)

Saffron (Crocus sativus) is one of the most valuable spices and therefore exceptionally vulnerable to fraudulent practices. Established methods for authentication depend on laboratory infrastructure and qualified personnel. To circumvent this dependency, a cost-effective test must be developed that allows the detection of foreign plant material rapidly and in a manner suitable for in-field analysis. The LAMP reaction is widely used for point-of-care diagnostic because of its robustness, reaction speed, and the independence from laboratory environment. Safflower (Carthamus tinctorius) as well as turmeric (Curcuma longa) is commonly used to stretch saffron. To detect adulteration, a primer set selective for the internal transcribed spacer sequence of safflower was designed in the present study and used in combination with a primerset selective for turmeric published by Sheu et al., in 2021. Here we present a LAMP-based rapid test system for detection of the adulterants turmeric and safflower in saffron samples. The developed rapid test system can be performed within 25 min and consists of an isolation protocol, a LAMP-assay, and visualization of the test result with a lateral-flow-assay. •Amplifiable DNA from safflower and turmeric can be isolated by one-step protocol.•Specific LAMP-primerset for safflower was designed based on rDNA.•Point-of-care suitable detection of adulterants is possible in less than 25 min.