title: Determination of mycotoxins in milk-based products and infant formula using stable isotope dilution assay and liquid chromatography tandem mass spectrometry.
abstract: A stable isotope dilution assay and liquid chromatography tandem mass spectrometry (LC-MS/MS) method was developed and validated for the determination of 12 mycotoxins, aflatoxins B₁, B₂, G₁, G₂, and M₁, deoxynivalenol, fumonisins B₁, B₂, and B₃, ochratoxin A, T-2 toxin, and zearalenone, in milk-based infant formula and foods. Samples were fortified with 12 ¹³C uniformly labeled mycotoxins ([¹³C]-mycotoxins) that correspond to the 12 target mycotoxins and prepared by dilution and filtration, followed by LC-MS/MS analysis. Quantitation was achieved using the relative response factors of [¹³C]-mycotoxins and target mycotoxins. The average recoveries in fortified milk, milk-based infant formula, milk powder, and baby yogurt of aflatoxins B₁, B₂, G₁, and G₂ (2, 10, and 50 μg/kg), aflatoxin M₁ (0.5, 2.5, and 12.5 μg/kg), deoxynivalenol, fumonisins B₁, B₂, and B₃ (40, 200, and 1000 μg/kg), ochratoxin A, T-2 toxin, and zearalenone (20, 100, and 500 μg/kg), range from 89 to 126% with RSDs of <20%. The individual recoveries in the four fortified matrices range from 72% (fumonisin B₃, 20 μg/kg, milk-based infant formula) to 136% (T-2 toxin, 20 μg/kg, milk powder), with RSDs ranging from 2 to 25%. The limits of quantitation (LOQs) were from 0.01 μg/kg (aflatoxin M₁) to 2 (fumonisin B₁) μg/kg. Aflatoxin M₁ was detected in two European Reference materials at 0.127 ± 0.013 μg/kg (certified value = 0.111 ± 0.018 μg/kg) and 0.46 ± 0.04 μg/kg (certified value = 0.44 ± 0.06 μg/kg), respectively. In 60 local market samples, aflatoxins B₁ (1.14 ± 0.10 μg/kg) and B₂ (0.20 ± 0.03 μg/kg) were detected in one milk powder sample. Aflatoxin M₁ was detected in three imported samples (condensed milk, milk-based infant formula, and table cream), ranging from 0.10 to 0.40 μg/kg. The validated method provides sufficient selectivity, sensitivity, accuracy, and reproducibility to screen for aflatoxin M₁ at nanograms per kilogram concentrations and other mycotoxins, without using standard addition or matrix-matched calibration to compensate for matrix effects.
authors.affiliation: Center for Food Safety and Applied Nutrition, Office of Regulatory Science, HFS-706, U.S. Food and Drug Administration, 5100 Paint Branch Parkway, College Park, Maryland 20740, USA. kai.zhang@fda.hhs.gov
authors.forename: Kai
authors.initials: K
authors.lastname: Zhang
authors.forename: Jon W
authors.initials: JW
authors.lastname: Wong
authors.forename: Douglas G
authors.initials: DG
authors.lastname: Hayward
authors.forename: Marta
authors.initials: M
authors.lastname: Vaclavikova
authors.forename: Chia-Ding
authors.initials: CD
authors.lastname: Liao
authors.forename: Mary W
authors.initials: MW
authors.lastname: Trucksess
mesh_terms: D000328:Adult; D002648:Child; D003611:Dairy Products / Q000032:analysis*; D005506:Food Contamination; D005513:Food Inspection / Q000379:methods*; D006801:Humans; D007223:Infant; D041943:Infant Formula / Q000737:chemistry*; D009183:Mycotoxins / Q000032:analysis* / Q000737:chemistry
chemical_list: D009183:Mycotoxins