Mutagenic modification effect of some edible mushrooms on nitrite treated beef concentrate using Ames test

Abstract

It was found that the concentrates from beef boiled with various amounts of four edible mushrooms namely, button, shiitake, oyster and abalone mushrooms did not show the mutagenicity when tested with the Ames test using Salmonella typhimurium strains TA98 and TA100 in the absence of metabolic activation. However, after nitrosation with nitrite they could exert the mutagenicity towards both strains. Thus, it was indicated that some mutagen precursors presented in all concentrates could interact with nitrite and addition of these edible mushrooms could not reduce the formation of these mutagen precursors. The same results obtained from studies of beef concentrate and these mushroom extracts. The results also showed that the addition of each mushroom extract to the beef concentrate before treated with nitrite did not reduce the mutagenicity of nitrite treated beef concentrate. However, the actual mutagenicity of the mixtures of some mushroom extract and beef concentrate treated with nitrite was less than the calculated values obtained by summing the mutagenicity of nitrite treated mushroom extracts and nitrite treated beef concentrate. Exceptions were found in button and oyster mushroom extracts that the actual mutagenicity of these two mixtures were higher than the calculated mutagenicity on S. typhimurium strain TA98. The mechanism of this synergistic effect should be further investigated.