Correlation of heavy metal concentrations with various factors in canned liver paste products using multivariate statistical strategies

The content of Cu, Fe, Mn, Zn, Co, Cr, Ni, and Pb were determined in 496 samples of heat-treated canned liver pastes by atomic absorption spectrometry. Canned samples were classified according to the presence or absence of coated varnish on the inner side of the can. For each sample, two subsamples were taken: one from the area in contact with the side of the can. the other from the center of the container. Univariate (correlation, box and whisker) and multivariate (quality control charts, principal component analysis, and factor analysis) statistical techniques were applied to detect the presence of outliers and for exploratory data analysis. No significant differences (P < 0.05) were found between the subsamples considered, presence or absence of coated varnish, the sampling areas, or countries of origin. The multivariate analysis allows for the interpretation of grouping tendencies in samples. Cr, Ni, and Pb were associated with presence or absence of oxide in the can, and the essential metals (Fe, Cu, Zn, and Co) were associated with the kind of can. The samples tended to differentiate according to the type of container.