Nondestructive Detection Of Melamine And Pesticide Residue In The Milk Products Based On Raman And VIS/NIR Spectroscopy Technology

With the development of market economy, people’s food consumption turns from quantity to the quality. People pay more attention to food safety. In recent years, media exposured a large number of milk product safety issues, espacially melamine and pesticides residues.They led to a lot of infant kidney stones, kidney failure, and even death. And they made serious damage to the family and social. Therefore, the current focus of research is to make a rapid, easy method to monitore melamine and pesticide residues. This paper introduces a nondestructive detection technology of melamine and pesticide residue in the milk products, including the following aspects:(1) Raman experiment device is used to detect blank milk power, pure melamine and concentration of0.1%,0.5%,1%,3%,5%,10%melamine in milk power.Then, I use the partial least squares and cluster analysis to identify the melamine concentration, respectively.When main factor is three, the correlation coefficient (r) and RMSE is0.9836and0.6209, respectively, in the partial least squares model.The detection limit is0.1%.In clustering analysis,when six concentration of melamine milk power divided into four categories, it shows judging correctly.The detection limit is1%. So, partial least squares and cluster analysis can effectively distinguish melamine concentration.(2) The study discusses how visible-near infrared spectroscopy (VIS-NIRS) can be used to detect the melamine in the milk. Through adulterating0-1000ppm content of melamine into pure milk,165samples were prepared in all. The spectra are recorded in the Vis-NIR range from350to1800nm using the fiber spectrometer. Partial least square (PLS), interval partial least square (IPLS) and synergy interval partial least square (SIPLS) methods were used to establish the calibration models of melamine. The results showed that the optimal SIPLS model is obtained with10intervals and the optimal combinations of three intervals are number4,7,9. The r between the predicted and actual melamine is0.9981and0.9946for calibration and prediction set, respectively. The root mean square error of calibration (RMSEC) and prediction (RMSEP) set was0.1942and0.3299, respectively. Compared with the national standard of high performance liquid chromatography, gas chromatography/mass spectrometry method, visible-near infrared spectroscopy combined with synergy inspection interval partial least square method is more convenient, fast.(3) MSC and SNV were used to pretreat VIS/NIR spectra of methamidophos and DDVP.And then I use the partial least squares to build models.The experimental results show that the r is highest after SNV.Therefore, VIS/NIR spectroscopy technology can be used to detect methamidophos and DDVP residue in the milk.It provides reference to pesticide residue in the milk.Lastly, I summary the nondestructive detection technology of melamine, methamidophos and DDVP in milk products, and puts forward many improvement scheme.