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A variety of dairy and soy-based dairy replacement products (n = 246) purchased from Canadian retail outlets were analysed for baseline levels of melamine (MEL) using a sensitive LC-MS/MS method (method quantification limit = 4 µg/kg). MEL was infrequently detected; only 14% of the items analysed contained quantifiable levels of MEL. The concentrations observed, aside from one recalled sample of candy, ranged from 0.00435 to 0.276 mg/kg, and were at least 10 times lower than the 2.5 mg/kg interim standard for melamine in products containing milk and milk-derived ingredients established by Health Canada. The consumption of foods containing these low levels of MEL does not constitute a health risk for consumers. [ABSTRACT FROM AUTHOR]

A variety of egg-containing, soy-based, fish, shrimp and vegetable products sold in Canada were analysed for melamine (MEL) using a sensitive solid-phase extraction LC-MS/MS analytical method. MEL was detected above the method quantification limit of 0.004 mg/kg in 98 of the 378 samples analysed. Concentrations in the various food product groups ranged 0.00507-0.247 mg/kg (egg-containing items), 0.00408-0.0479 mg/kg (soy-based meat substitutes), 0.00409-1.10 mg/kg (fish and shrimp products), and 0.00464-0.688 mg/kg (vegetable products). MEL was detected less frequently in egg- and soy-containing products. The presence of MEL in most of the Canadian Total Diet Study shrimp composites collected after 2001 suggested the residues in shrimp were caused by a relatively recent exposure to MEL. All concentrations of MEL reported were lower than the 2.5 mg/kg interim standard established for MEL in items containing milk and milk-derived ingredients and the respective maximum residue limits for cyromazine and its metabolite, melamine, in vegetables set by the Canadian Government (2009; http://www.hc-sc.gc.ca/fn-an/securit/chem-chim/melamine/qa-melamine-qr-eng.php#8). The consumption of foods containing these low levels of MEL does not constitute a health risk for consumers. [ABSTRACT FROM AUTHOR]

An analytical method incorporating simple liquid extraction followed by mixed mode cation exchange/reversed phase solid phase extraction and liquid chromatography-tandem mass spectrometry was developed and validated for the analysis of melamine (MEL) in liquid and powdered infant formula. The method used two different MEL stable isotope labeled internal standards to monitor analyte recoveries and to account for matrix effects. The method is sensitive (limit of quantitation of 4 ng/g), accurate, and precise (during validation, recoveries corrected by internal recovery standard averaged between 92 and 104% for all fortification levels and matrices). The method was used to analyze 94 samples of infant formula purchased from major retailers in Ottawa, ON, Canada, to examine whether or not Canadian infants are exposed to background levels of MEL. MEL was detected in 71 of the 94 products analyzed at concentrations ranging from 4.31 to 346 ng/g (median = 16 ng/g). A comparison of estimated dietary exposures to the recently recommended World Health Organization toxicological reference value for melamine suggests that the presence of low levels of MEL in infant formula purchased in Canada does not represent a health risk.