Assessment of Cadmium and Mercury Contamination of Milk and Dairy Products in Vietnam

Background: Milk and dairy products are nutritious and can play a significant role in a healthy diet. The safety of milk decreases with increase in concentration of Cadmium (Cd) and Mercury (Hg). The aim is to evaluate the status of Cd and Hg contamination regarding milk and dairy products in some provinces and cities of Vietnam. Methods: 367 samples of liquid milk, yogurt, cheese, milk cake and milk powder were collected in six large cities and provinces of Vietnam, then Cd and Hg levels were quantitatively analyzed. Samples were digested before analysis to remove organic compounds, and the heavy metal concentrations were determined by atomic absorption spectrophotometry. Results: The average concentrations of Cd and Hg in liquid milk were 64.55 and 29.99 ppb; in yogurt, 49.09 and 24.72 ppb; in cheese, 115.81 and 33.75 ppb; in milk cake, 84.44 and 18.08 ppb; and in milk powder, 61.78 and 43.21 ppb, respectively. Conclusion: Hg concentrations in 19.3% of liquid milk, 9.49% of yogurt, 14.29% of cheese, 9.09% of milk cake, and 22% of milk powder were higher than the maximum permitted levels according to national regulations. In contrast, Cd concentrations of all the samples were less than the maximum permitted levels so as not to affect the health of consumers of milk and dairy products produced and processed in Vietnam.