Abstract
<title>Abstract</title> <p> Achieving accurate quantification and counting of active LAB is an important technical guarantee for the industrial production and application of LAB and their products. In this study, an AuNPs@PVP/SA hydrogel SERS sensor with outstanding stability and sensitivity was developed. Utilizing this platform as a substrate material to mitigate the “coffee ring” effect, we explored a strategy for the precise quantitative analysis of mixed active lactic acid bacteria (LAB) based on the AuNPs@PVP/SA hydrogel SERS platform and D <sub>2</sub> O-probed Raman spectroscopy technology. The results indicated that the SERS platform based on AuNPs@PVP/SA hydrogel exhibited excellent spectral reproducibility for LAB as a SERS substrate material, with a significantly reduced “coffee ring” effect. This strategy has excellent analytical capabilities for the qualitative identification and precise quantification of different species of active LAB in actual samples, achieving an average accuracy rate of 98.67% with <italic>RSD</italic> values all less than 5%. It provides a potential technical support for the dynamic monitoring of relative abundance and metabolic phenomena of mixed active LAB in co-culture systems during actual industrial production. </p>