2013 Volume 20 Issue 2 Pages 96-104
For easy and rapid DNA extraction from processed foods, we developed a new silica membrane-based DNA extraction method. DNA extraction conditions suitable for processed foods were examined based on an existing DNA extraction kit for raw grain materials, GM quicker 2. Twenty microliters of proteinase K solution (20mg/ml) was used for cell lysis and the digestion was carried out at 65℃ for 30min. In addition, 200μl for wet processed foods or 400μl for dry processed foods of 2.0 M potassium acetate (pH 3.7) and 600μl of 8.0 M guanidine hydrochloride were adopted as buffers to achieve good DNA recovery from cell lysates. The novel method was compared to four conventional methods using six kinds of processed foods as analytical samples, i.e., roasted soybean flour, soy milk, miso, canned whole kernel sweet corn, corn snack and dried soup mix. The developed method showed wide applicability to various process foods and it gave sufficient amounts of DNA with high purity. Also, the method was highly user-friendly because of the short handling time, the small number of pipette operations and non-use of toxic organic solvents. The method would be practically used for food testing to detect genetically modified organisms, allergens, pathogenic microorganisms and so on.
