Identification of species falsification of cod liver by polymerase chain reaction

Abstract

With the increase in consumer demand for fish products, the number of enterprises offering their products on the market has increased, which has led to a decrease in the quality of these goods. Cod liver is an expensive raw material for the production of canned food. In order to reduce production costs, manufacturers replace cod liver with salmon milk, in particular pink salmon, which is a species falsification. Modern methods of fish and fish products research are used to detect falsification in laboratory practice. The advantage of this method is that it is the most specific and sensitive for identifying the species of the raw material composition of the product and the finished product, since the DNA molecule does not lose its ability to perform an informative function under the influence of physical or chemical parameters, which characterizes it as the most stable structure of any animal organism. The research was carried out in the conditions of the Department of Molecular Research of the North-Western branch of the FGBI VNIIZH. The research material was 12 samples of canned fish sterilized from the liver of Atlantic cod. At the first stage, sample preparation was carried out by homogenizing samples into mortars, then 8 samples of each sample were taken, DNA extraction was carried out using a set of "GMO-Sorb-B". At the next stage, using the "Rotor-Gene 6000" amplifier, a polymerase chain reaction was set up, using kits for detecting the DNA of cod, haddock, pollock and DNA of salmon fish and differentiating species: pink salmon, chum salmon and sockeye salmon. As a result of the conducted studies, it was established that the liver of cod declared in the composition was not detected in one sample, since the content of cod fish was not detected in all samples from this sample, but the presence of pink salmon DNA was established. The results obtained indicate the specific falsification of canned cod liver.