# Development and Application of a Polymerase Spiral Reaction (PSR)-Based Isothermal Assay for Rapid Detection of Yak (Bos grunniens) Meat

## TL;DR

This paper introduces a new, fast, and affordable method to detect yak meat using a DNA-based test that works well in various food samples.

## Contribution

The first PSR-based isothermal assay for yak meat detection, offering improved sensitivity and field-applicability.

## Key findings

- The PSR assay can detect yak DNA at 1 pg sensitivity and up to 0.1% in beef mixtures.
- The method shows no cross-reactivity with other common meat species.
- The assay performs reliably even after thermal processing up to 121 °C.

## Abstract

The growing demand for robust food authentication methods has driven the establishment of fast, sensitive, and field-based detection systems for identifying meat species. This study presents a colorimetric-based PSR approach for identifying yak (Bos grunniens) meat within fresh, thermally processed, and blended meat samples. Targeting the mitochondrial D-loop locus, the assay incorporates a simple alkaline lysis (AL) procedure for efficient DNA extraction, eliminating the requirement for specialized instrumentation. The PSR assay demonstrated high specificity, showing no evidence of cross-reactivity with closely associated food animals such as buffalo, cattle, goat, sheep, mithun, and pig. Sensitivity assessment revealed the assay’s capability to detect 1 pg of yak DNA, with reliable performance in samples exposed to thermal conditions up to 121 °C. Additionally, the technique detected yak meat down to a concentration of 0.1% in binary beef mixtures. This method provides a significant improvement in sensitivity over end-point PCR and is particularly well-suited for field applications due to its practical simplicity, affordability, as well as no reliance on sophisticated instrument. This is, to the best of our understanding, the first reported PSR-based approach developed for the identification of yak meat, offering a robust tool for food origin verification, regulatory enforcement, and product integrity monitoring.