Detection and quantitation of mycotoxins in infant cereals in the U.S. market by LC-MS/MS using a stable isotope dilution assay

• LC-MS/MS was developed and validated for determination of 11 mycotoxins.
• 78% of infant cereals were contaminated with at least one of these mycotoxins.
• Co-contamination of multiple mycotoxins was found in oat-based infant cereals.

The aim of this study was to develop an analytical method for the simultaneous determination of aflatoxins B1, B2, G1, G2, ochratoxin A, fumonisins B1 and B2, zearalenone, deoxynivalenol, T-2 toxin, and HT-2 toxin in infant cereals using rapid liquid chromatography-tandem mass spectrometry (LC-MS/MS). Another goal was to survey infant cereals purchased in the United States for the presence and amounts of 11 mycotoxins. Separation of the mycotoxins was accomplished using ultra-high performance liquid chromatography (UHPLC) with <10 min analysis time. The toxins were then detected by dynamic multiple reaction monitoring (dMRM) in positive electrospray ionization mode. Due to matrix effects, [13C]-uniformly labeled mycotoxins were added to the sample extracts prior to LC-MS/MS analysis. Overall recoveries of mycotoxins were 81–130% in rice, 70–119% in barley, 87–123% in oat, and 82–127% in mixed-grain cereals with lower recoveries for fumonisins B1 and B2, (33–67%) at three spiking levels (12.5, 25 and 50 ng/g). The relative standard deviation was <20% for all analytes in the infant cereals. When this method was applied to measure mycotoxin concentrations in infant cereals (n = 64) purchased in the U.S. in 2012, 78% of infant cereals were found to be contaminated with at least one of these mycotoxins. None of the infant cereals exceeded the established regulatory limits in the United States for any of the analyzed mycotoxins. However, a total of 21 samples exceeded the European Union maximum limits for three of the mycotoxins including aflatoxin B1, ochratoxin A and zearalenone. Results of this study suggest that cereals intended for infants should be routinely monitored for mycotoxin content.