To develop a fast, economical and sensitive method for determining the dioxin-like persistent organic pollutants (POPs) in infant formula, milk and milk-based products.MethodsLipid extraction efficiencies of traditional sample extraction (Soxhlet extraction) and acid digestion liquid-liquid extraction (LLE) were compared. ResultsFor infant formula, lipid contents (%) determined by direct Soxhlet extraction (19.6±2.0) and by LLE (20.9±1.2) were close to the nutrition label (21.8±1.3), and the differences in efficiency between these two methods were not significant (t-test, P>0.05). For fresh cow milk and other milk powder however, lipid contents (%) determined by direct Soxhlet extraction were much lower than the nutrition label.ConclusionSoxhlet extraction was not suitable for non-infant formula milk powder or fresh cow milk, whereas acid digestion LLE results accorded well with the true lipid content for all types of dairy products tested. This was due to different proportion of whey protein to casein in infant formula and other kinds of milk powder.