Real-Time PCR Detection of Adulteration of Olive Oil With Soybean Oil Based on Optimized CTAB DNA Extraction Method

This study established an optimized CTAB-based DNA extraction method for edible oils, which enables stable and reliable DNA recovery from commercially available edible oils for authenticity identification and adulteration detection. Real-time PCR was used to assess DNA precipitation time and organic solvent extraction, revealing that longer precipitation increased inhibitors, hindering PCR amplification, while organic solvents enhanced efficiency. The method was applied to detect adulteration in commercially available soybean and olive oils. A standard curve based on real-time PCR Ct values demonstrated the ability to detect as low as 10% soybean oil in olive oil, with recovery rates of 92% and 80% for samples spiked with 70% and 30% soybean oil, respectively. The coefficients of variation (CV) were 11% and 14%, within acceptable ranges. This reliable method provides a valuable tool for edible oil authentication and adulteration detection.