Species Authentication And Geographical Origin Traceability Of Imported Salmon

Salmon,the scientific name of Atlantic salmon（Salmo salar）,belongs to the family Salmonidae and the genera Salmo.Because of its high protein,low fat,low cholesterol,rich in vitamins,and delicious taste,it is fond of Chinese consumers.Because salmon is a cold-water migratory fish,its living conditions are relatively harsh,and China cannot temporarily farm large-scale,so our country mainly depends on imports.With the improvement of the quality of life of our nationals,trade competition has intensified,the quality of Atlantic salmon meat and fish products in our country’s market are the bad become mixed with the good,and imported salmon has to face up with problems such as confusion of origin labels and difficulty in distinguishing true from false.In order to strengthen the quality and safety management of imported salmon and effectively protect the rights and interests of consumers,it is urgent to establish a technical system for salmon authenticity identification and origin traceability.For this reason,our study used the partial sequence of the mitochondrial cytochrome oxidase C subunit I gene（COI）,which is widely used in animal classification and identification,as the target gene to evaluate the applicability of DNA barcode technology in the identification of salmon species;The feasibility of tracing the origin of imported salmon with fingerprints of mineral elements and near infrared spectroscopy technology was discussed.The main results are as follows:（1）Identification of salmon species based on DNA barcode technology:Mitochondrial COI sequences of 8 genera and 29 species of salmon were analyzed by PCR specific amplification and sequencing in combination with Gen Bank sequences.The results show that the average interspecific genetic distance of salmonids is 0.150,which is 150 times the ave rage intraspecific genetic distance（0.001）;on the molecular phylogenetic tree,the same salmonid species are gathered in the same independent branch with a higher support rate.The above results indicate that the DNA barcode technology based on the COI gene can be effectively applied to the authenticity research of salmon.（2）Research on origin traceability of salmon based on mineral element fingerprint:Inductively coupled plasma mass spectrometer（ICP-MS）and inductively coupled plasma spectrometer（IC P-OES）were used to determine16 mineral elements（Pb,Fe,Cu,Zn,Al,Sr,Ni,As,Cr,V,Se,Mn,K,Ca,Na,Mg）.Multivariate statistical methods including analysis of variance（ANOVA）,principal component analysis（PCA）and linear discriminant analysis（DA）were used to analyze the content of the mineral element,it was found that Fe,Zn,Al,Ni,As,Cr,V,Se,Ca and Na can be used as characteristic elements of salmon to characterize their geography source.The discriminant model based on these elements has an overall and cross-validation discrimination rate of 98.8%for salmon.The results show that the mineral element fingerprint combined with the stoichiometric method can be used as an effective method to spot the origin of salmon imported from Norway and Chile.（3）Research on origin traceability of salmon based on near-infrared spectroscopy:Fourier near-infrared spectroscopy was used to collect Norwegian and Chilean salmon near-infrared spectroscopy data,and the spectral data was preprocessed by different methods to establish a discrimination model.The results show that in the full wavelength range of12000～4000cm^-1,the use of spectral data with first derivative+SG9 point smoothing pretreatment combined with principal component analysis（PCA）and partial least squares（PLS）analysis can effectively The origin of imported salmon is traced,and the discrimination effect reach 98%and 98.5%.Therefore,compared with the mineral element fingerprint technology,the traceability model of imported salmon established by near infrared spectroscopy is more robust.