Assessment of the mutagenicity of instant noodles and their seasonings, using Ames test

Abstract

The mutagenicity of three kinds of instant noodles, namely minced pork flavour, pa-lo duck flavour and sour shrimp flavour were investigated in this study. It was found that all extracts from instant noodles, from seasonings and from noodles cooked with seasonings were not mutagenic when tested on Salmonella typhimurium strains TA 98 and TA 100 of the Ames test in the absence of activating system. However, after being treated with nitrite in acid circumstance (pH 3-3.5) at 37℃ for 4 h, they all showed the direct mutagenicity towards the bacteria. The nitrite treated extracts from seasoning, expressed as number of revertants per gram, showed the highest mutagenicity because it was composed of meat extract, spice and other components such as caramel, which could interact with nitrite and showed direct mutagenicity towards the bacteria. Comparing between expected values calculated from summation of number of revertant colonies per package of noodle only and number of revertant colonies per package of seasoning only and actual values from experiment, it was found that expected values were higher than actual values. It was suggested that extractable material from wheat flour in the noodle could trap the mutagen precursor from interacting with nitrite during the 4-h incubation. Therefore, the consumption of instant noodles with nitrite containing food is not recommened. Also, it is suggested to consume less seasoning as possible or use homemade fresh meat stock instead. In addition, it is advised to rinse the noodle with hot water before cooking.