Isolation of DNA from food and food ingredients can present a host of difficulties to the analytical scientist, writes Dr Jacqui Coutts. Unlike the average blood or tissue sample, foods and food ingredients presented for analysis may have undergone a variety of high temperature and pressure treatments.
The presence of high fat, starch or protein levels can also have a direct effect on the quality and quantity of DNA extracted. Many of the methods currently employed by laboratories for DNA extraction from food are adapted from clinical methods and contain at least one DNA precipitation step. It is at this stage where starches and proteins can also be precipitated resulting in a adirty', poor quality extract.
Tepnel BioSystems' BioKits range of DNA extraction kits (GMO & Allergen and Speciation) have been developed specifically for the extraction of DNA from food samples. The need for a manual precipitation step is completely avoided by the use of magnetic beads which bind DNA from a sample lysate. The bead/DNA complex is washed with an ethanol solution and the DNA then simply eluted off the beads with water. There is no requirement for chemicals such as phenol or chloroform and very few centrifugation steps.
Clearly, a DNA Extraction procedure specifically developed for food samples is invaluable when solving extraction problems. The need is foreseen to grow with the increasing applications for DNA analysis.
Enter 31 or at www.scientistlive.com/efood
Dr Jacqui Coutts is with Tepnel BioSystems Ltd, Deeside, Flintshire, UK. www.tepnel.com
