Cereal Chem. 71:207-215   |  VIEW ARTICLE


Occurrence of Ethyl Carbamate (Urethane) in U.S. and Canadian Breads: Measurements by Gas Chromatography-Mass Spectrometry.

W. F. Haddon, M. L. Mancini, M. McLaren, A. Effio, L. A. Harden, R. L. Degre, and J. L. Bradford. Copyright 1994 by the American Association of Cereal Chemists, Inc. 

In a survey of U.S. and Canadian breads, urethane, a chemical shown to be carcinogenic in animals, was detected at low levels in 22 batches of commercial breads and rolls that were sampled immediately after baking. The mean level of urethane was 2.06 plus/minus 0.2 ppb for measurements on composite samples of 12 loaves prepared using established procedures for trace nutrient analysis. The mean value of urethane was less than one third the 7-ppb value used by others to estimate probable nonalcohol human dietary exposure to urethane. Based on the newly determined mean level for urethane and bread consumption data, the per capita dietary intake per year in the United States is 47 plus/minus 4 micrograms for untoasted bread. Chemically specific gas-chromatographic detectors employing either high-resolution mass spectrometry or methane chemical-ionization mass spectrometry were used for all measurements, yielding a quantification precision of plus/minus 0.2 ppb at the 1-ppb level. The average recovery of urethane from white bread was 110% in the 3-7 ppb range.