Detection of Melamine and Cyanuric Acid in Vegetable Protein Products Used in Food Production

  The multitude of food recalls in 2007 clearly demonstrated that total nitrogen‐content (Σ N ) determination by means of near‐infrared spectroscopy (NIRS) and Kjeldahl‐based measurements can be deceived, and should no longer be regarded as a complete quality assurance program for nutritive‐protein evaluations. Furthermore, contemporary Canadian‐employed analytical tools are precariously limited in their ability to effectively assure a product where there is no  a priori  knowledge of the environmental toxin(s) involved. In light of these challenges, this study explored a number of analytical techniques used to assess and furthermore assure the quality of vegetable protein products (VPPs). Using liquid chromatography with tandem mass spectrometry (LC/MS/MS) technologies, a combination of VPP‐based samples was analyzed for the presence of nitrogen‐bearing environmental toxicants. Of the 52 samples tested, involving an assortment of matrices, melamine and cyanuric acid were positively identified (>1 ng/mL) in 22 and 17 samples, respectively. Subsequent high pressure liquid chromatography with ultraviolet/visible (HPLC‐UV) amino acid profiling further confirmed the adulteration of those materials contaminated with melamine and melamine‐related compounds. Based on the evidence presented herein, LC/MS/MS in combination with HPLC‐UV provides for a reliable food safety detection system as applied to VPPs. Moreover, HPLC‐UV is indispensable as a stand‐alone 1st level of screening to assess the integrity of a VPP or any nutritive protein‐based sample. Practical Application:  Based on the evidence presented herein, LC/MS/MS in combination with HPLC‐UV can provide a reliable food safety monitoring program as applied to VPPs. HPLC‐UV is indispensable as a stand‐alone 1st level of screening to assess the integrity of a VPP or any nutritive protein‐based sample. Future research and development is required to bring the associated instrumentation costs down to a level where they can be adopted on a widespread basis.