Folic Acid Content of Ready-to-Eat Cereals Determined by Liquid Chromatography-Mass Spectrometry: Comparison to Product Label
and to Values Determined by Microbiological Assay

Katherine M. Phillips (1,2), David M. Ruggio (1), Mehdi Ashraf-Khorassani (3), Ronald R. Eitenmiller (4), Sungeun Cho (4), Linda E. Lemar (5), Charles R. Perry (5), Pamela R. Pehrsson (5), and Joanne M. Holden (5).

(1) Biochemistry Department (0308), Virginia Polytechnic Institute and State University, Blacksburg, VA 24061. (2) Corresponding author. Phone: (540) 231-9960. Fax: (540) 231-9070. E-mail: <kmpvpi@vt.edu> (3) Chemistry Department, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061. (4) Department of Food Science and Technology, University of Georgia, Athens, GA 30602. (5) USDA ARS, Beltsville Human Nutrition Research Center, Nutrient Data Laboratory, 10300 Baltimore Blvd., Bldg. 005, Room 107, Beltsville, MD 20705. Cereal Chem. 87(1):42-49. Accepted July 8, 2009. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. AACC International, Inc., 2010.

Abstract: Twelve popular ready-to-eat breakfast cereals fortified with folic acid were sampled in the United States in 2006, and the data have been incorporated into the USDA National Nutrient Database for Standard Reference. Cereals were collected from three statistically selected retail outlets in each of four primary census regions, and four composites of each product were prepared using random groupings of three locations each. Folic acid was determined using a validated LC-MS method, with (^13)C-folic acid as an internal standard, after trienzyme treatment and solid phase extraction. A cereal reference material (AACC VMA399) was analyzed as a control. Selected samples were also assayed using the standard microbiological method, with and without trienzyme extraction, to generate an estimate of endogenous folate. On average, as shown on the label, folate content was underestimated. In seven cereals, folate was within 5% of the declared value; in four cereals, it was 5–20% higher; and in two cereals, it was >20% greater, representing –75 to +69 µg/serving (mean 17) of the label value, equivalent to –19% to +17% of the 400 µg/daily value. The microbiologically determined folic acid was higher than LC-MS by 10–67% (mean 40%). Therefore, use of label values might underestimate folate intake from some breakfast cereals.