Simultaneous determination of somatic cell count and total plate count in raw milk based on ATP bioluminescence assay

Abstract

The somatic cell count (SCC) and total plate count (TPC) are essential quality indicators for raw milk. Traditional detection methods require separate measurements and rely on complex, large-scale instruments or cultivation techniques, which are both time-consuming and laborious. To address these challenges, this study developed a novel method for the simultaneous detection of SCC and TPC in the same raw milk sample using the ATP bioluminescence assay. This method utilizes oxy-ethylated iso-nonyl phenol (Neonol-10) and cetyltrimethylammonium bromide (CTAB) to selectively lyse somatic cells and microorganisms, respectively. This technique is straightforward to operate and can be completed within 2.5 h, with detection ranges of 1 × 10⁴ to 3 × 10⁶ cells/mL for SCC and 1 × 10⁵ to 5 × 10⁷ CFU/mL for TPC. Importantly, this technique meets the requirements of detection standards in China, European Union, Canada, United States, etc. For SCC or TPC in raw milk. Overall, this innovative approach does not rely on expensive equipment or facilities and the stepwise reagent addition procedure can be easily developed into an automated high-throughput system for rapid on-site testing of SCC and TPC in raw milk.