Evaluation of a rapid DNA extraction method to detect yeast cells by PCR in orange juice

Yeasts are the main causes of spoilage in pasteurized orange juice. Whereas detection by plate counting techniques is too slow to allow appropriate intervention measures, PCR reaction offers a rapid alternative, but it can be inhibited by components of food samples. We developed a DNA extraction method directly from orange juice for rapid yeast detection by PCR amplification of the rRNA internal transcribed spacers including the 5.8S rRNA gene at a detection limit of 103 cfu/ml juice sample. We show that it is possible to reduce detection time and improve detection rate of yeasts in orange juice by using a simple glass bead disruption procedure in connection with silica absorption and amplification technology.