Extraction of RNA from fermented milk products for in situ gene expression analysis.

This work describes a simple method for extracting high-quality microbial RNA from fermented milk. Pretreatment consists merely of adding a concentrated solution of sodium citrate to the milk product. The proposed method provides consistently better yields of high-quality RNA than the conventional method independent of the texture of the fermented milk. Furthermore, it can be used with small amounts of starting material, requiring only the use of Eppendorf-size centrifuges-a great advantage for analytical laboratories. The RNA obtained is suitable for the detection of live microorganisms and for transcriptional studies based on quantitative reverse transcription polymerase chain reaction (RT-qPCR).