Methods and Protocols

      The Ames Assay and assessment of Reduced-Risk Products


      Published on
      May 1, 2017

      The Ames Assay (or Bacterial Reverse Mutation Assay) is the most commonly used in vitro genotoxicity test and was designed to detect genetic damage and gene mutations induced by a range of single chemicals and complex environmental and biological mixtures[1].

      The test is recommended by the Organisation for Economic Co-operation and Development (OECD) and the International Conference on Harmonisation (ICH) as part of the standard testing set for genotoxicity[2][3].

      Ames Assay to assess Reduced-Risk Products

      The Ames Assay can discriminate the mutagenic activity of total particulate matter (TPM) from different types of cigarette with different filter ventilation, filter efficiency and paper porosity[4][5]. It can also discriminate between tobacco types and cigarette smoke fractions[6] as well as between cigarettes and Reduced-Risk Products (RRPs).[4]

      We perform the Ames test in compliance with OECD guideline 471[2], taking into account that TPM is known to be mutagenic. In each test, concurrent positive and negative controls are evaluated and used to confirm the test performance.

      As can be seen in the graph below, we tested a range of doses of TPM from our RRP Platform 1 (regular and menthol) and 3R4F[7]. The graph very clearly shows that even at concentrations of TPM significantly higher than the maximum dose of TPM from 3R4F, the number of mutation revertants found in the bacteria exposed to TPM from Platform 1 was significantly reduced. 


      Genotoxicity in bacterial cells substantially decreased compared to 3R4F Note: these data alone do not imply or represent a claim of reduced exposure or reduced risk.


      [1] Maron, DM and BN Ames. Revised methods for the Salmonella mutagenicity test. Mutat Res, 1983. 113(3-4): p. 173-215. Available online at:

      [2] OECD. OECD guideline for the testing of chemicals: bacterial reverse mutation test. 1997.

      [3] International Conference on Harmonisation. Guidance on genotoxicity testing and data interpretation for pharmaceuticals intended for human use. 2011.

      [4] Roemer. E, et al. Discrimination of cigarette mainstream smoke condensates with the Salmonella reverse mutation assay. The Toxicologist, 1998. 42(1-S): p. 295.

      [5] Tewes. FJ, et al. Cigarette parameters that influence the mutagenicity of mainstream smoke condensate. The Toxicologist 1999. 48(1-S): p. 296.

      [6] DeMarini, DM. Genotoxicity of tobacco smoke and tobacco smoke condensate. Mutat Res, 1983. 114(1): p. 59-89. Available online at: [

      [7] Philip Morris International Investor Day Presentation, 26 June 2014. Available online at: