Testing of a Detection Protocol for Genetically Modified Food Probably Found in Sudanese Markets

Abstract

In recent years, genetically modified foods (GMFs) found their way to the international food markets, particularly those of under-developed countries. The safety of the GMF is a controversial issue, even in the scientific community, and great concern was raised by consumers and legislators. The consumers had the right to know whether their food or some of it is genetically modified. The aim of this study was to develop and test a protocol to detect GMFs in the Sudanese food markets. The study targeted soybean (seeds and isolated proteins) and cotton seeds as both could be used directly or indirectly in human foods. The collected samples were examined for the presence of 35s promoter and NOS terminator using a DNA/based - polymerase chain reaction (PCR) and real time PCR. DNA was extracted from the samples and its purity and concentration were determined. Mineral content was determined with inductively coupled plasma with mass spectrometry (ICP-MS) and the fatty acid profile with GC. In addition, the peroxide value (PV) and proximate composition of the samples were also determined. The results showed that the DNA of all samples under investigation had concentrations in the range of 500 -1500 ng/ul and a purity of 66%-89%. Real time PCR showed that cotton seed cake samples were + ve for TNOS and 35s primers, while isolated soy protein sample was + ve only for 35s primer and -ve for TNOS. Soybean seeds and isolated soybean protein were all -ve for both primers and as such not genetically modified. The chemical and biochemical analysis of GMFs and non GMFs showed some differences that cannot be attributed to the genetic modification alone at this juncture. It is concluded that the protocol used is an effective one, and the real time PCR is a sensitive technique for the detection of genetically modified foods, yet further studies by accredited laboratories are strongly recommended.