N-glycolylneuraminic acid as a specific marker for goat milk adulteration detection: Development and application

Dairy quality and safety are critical in food supervision, with goat milk adulteration posing a major challenge. This study developed a sensitive HPLC-fluorescence method using N-glycolylneuraminic acid (Neu5Gc) as a specific marker to quantify bovine milk adulteration in goat milk. Analysis of pure goat milk samples from six breeds, four geographical origins, and different lactation seasons revealed that, despite variations attributed to these factors, Neu5Gc levels in goat milk were consistently more than 50-fold higher than those in bovine milk. Adulteration proportionally reduces Neu5Gc concentration. Linear regression models for water and bovine milk adulteration achieved R 2 values of 0.9857 and 0.9624, respectively, with mean absolute errors ≤4.0%. The method successfully identified commercial goat milk products adulterated with high proportions of bovine milk. Overall, this work provides a reliable and novel strategy for the authentication and quantitative adulteration analysis of goat milk, offering technical support for the supervision of dairy quality and safety.