Figure 1. Summary of protocol. The procedure is based on the reversible adsorption of nucleic acids to paramagnetic beads under specialized buffer conditions. Sample lysis is achieved by incubation of samples with Proteinase K at 65 °C. Lysis mixtures are cleared by centrifugation or filtration in order to remove contaminants and residual cellular debris. Nucleic acids are then bound to the paramagnetic beads via addition of Binding Buffer CB and the NucleoMag B-Beads to the cleared lysate. After magnetic separation, the paramagnetic beads are washed to remove contaminants and salts using Wash Buffers CMW, CQW, and 80% ethanol. Residual ethanol from previous wash steps is removed by air drying. Next, highly purified DNA is eluted with low-salt Elution Buffer (CE) and can be used directly in downstream applications. The NucleoMag DNA Food kit can either be used manually or automated on standard liquid handling instruments and automated magnetic separators.

Figure 2. Effective isolation of DNA from various food samples. Sample homogenization and lysis were performed manually, whereas DNA isolation was automated using a KingFisher Flex. DNA presence within the eluates was determined using qPCR.

Table I. Overview of different sample types that have been successfully tested. Following DNA extraction with the NucleoMag DNA Food kit, the presence of DNA was tested by either qPCR or via agarose gel electrophoresis.

Figure 3. Higher DNA yield with NucleoMag DNA Food versus a leading competitor. DNA from a variety of food sources was isolated using either the NucleoMag DNA Food (MN) or a competitor's kit (P) and DNA was detected using qPCR. The NucleoMag DNA Food kit consistently demonstrated lower Ct values than the competitor's kit, indicating a superior DNA yield.