Chemical analysis, prevention, and low-level dosimetry of heterocyclic amines from cooked food.
Potent mutagenic and carcinogenic heterocyclic amines are produced from heated food derived from muscle. These compounds are present at part-per-billion levels and consist primarily of the amino-imidazoazaarene class of chemicals. Additional mutagens present in the meat are not as clearly characterized. Commercial fried-beef patties (hamburgers) have low levels of 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) and 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (4,8-DiMeIQx), 0.1-0.68 ng/g meat for MeIQx and slightly lower for 4,8-DiMeIQx. The formation of these heterocyclic amines can be reduced by microwave pretreatment of meat, with the resulting liquid being poured off before frying. The Ames/Salmonella mutagenic activity was reduced to 5-10% of that of non-microwave-treated samples. MeIQx and DiMeIQx concentrations were reduced to 12% and 50% of levels in the non-microwave-treated samples, respectively. MeIQx adducts, as measured by accelerator mass spectrometry, were found to be linear with doses from 5 mg/kg to 500 ng/kg. Linear DNA binding at low doses is important for assuming linear risk estimation from the high animal-feeding doses causing cancer to the low human-dietary exposures. Extrapolating from the rodent TD50 dose to humans gives a maximum credible risk from consumption of heterocyclic amines of approximately 1/1000 exposed individuals.
Felton
J S
JS
Biomedical Sciences Division, Lawrence Livermore National Laboratory, University of California, Livermore 94550.
Knize
M G
MG
Roper
M
M
Fultz
E
E
Shen
N H
NH
Turteltaub
K W
KW
D004247:DNA / Q000378:metabolism; D005504:Food Analysis; D006571:Heterocyclic Compounds / Q000302:isolation & purification*; D006358:Hot Temperature; D006801:Humans; D007093:Imidazoles / Q000302:isolation & purification* / Q000378:metabolism / Q000633:toxicity; D008460:Meat; D009152:Mutagenicity Tests; D011804:Quinolines / Q000302:isolation & purification* / Q000378:metabolism / Q000633:toxicity; D011810:Quinoxalines / Q000302:isolation & purification* / Q000378:metabolism / Q000633:toxicity
D006571:Heterocyclic Compounds; D007093:Imidazoles; D011804:Quinolines; D011810:Quinoxalines; C029216:2-amino-3-methylimidazo(4,5-f)quinoline; C036990:2-amino-3,8-dimethylimidazo(4,5-f)quinoxaline; D004247:DNA; C049584:2-amino-1-methyl-6-phenylimidazo(4,5-b)pyridine; C042052:2-amino-3,7,8-trimethylimidazo(4,5-f)quinoxaline