Effect of pH and ammonium ions on mutagenic activity in cooked beef.

Controversy surrounding the extraction procedure commonly used for isolating and concentrating mutagens from foods has resulted in a need for the re-examination of the reported mutagenicity in fried hamburgers. Using a procedure in which Na2SO4 and NaOH are substituted for (NH4)2SO4 and NH4OH respectively, mutagenic activity in extracts of hamburgers fried for 5 min appeared to be unchanged. However, when organic extractions are performed at pH conditions more moderate than those generally employed to isolate mutagens from foods, a 30-50% decrease in mutagenicity is observed.