USP updates guidance on milk adulteration

The US Pharmacopeial Convention (USP) has continued its fight against food fraud with the publication of draft guidance on the detection of adulterants in milk and milk ingredients.

Specifically, the guidance - which is now open for public comment - covers ways to identify 41 nitrogen-containing adulterants which may be added to milk with the fraudulent intent of increasing its apparent protein content.

Adulterants include compounds such as melamine - which was behind the infamous scandal in China in 2008 which led to the deaths of six infants - as well as dicyandiamide. These have high nitrogen contents that boost apparent milk nitrogen content without significantly altering its appearance. Others with lower nitrogen content include agricultural chemicals such as fertilizer urea and biuret.

At the moment there is no standard procedure in USP's Food Chemicals Codex (FCC) for this purpose, and the proposed addition to Appendix XVI: Protein-Based Ingredients covers the use of ultra-high performance liquid chromatography and tandem mass spectrometry (UHPLC-MS/MS)

"The method proposed in this standard is capable of detecting very small amounts of suspected adulterants in bulk ingredients," said Gabriel Giancaspro, vice-president for foods, dietary supplements and herbal medicines at USP.

"Suspicious samples should still be referred to confirmatory tests," he added.

USP recently sent a letter to the FDA saying it should introduce specific measures to tackle economically-motivated adulteration (EMA) of food rather than rely on generic, preventive controls.