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Development Validation and Analysis of Salmonella Mutagenicity Test Methods

Water Quality Control

  1. Suparna Mukherji

Published Online: 15 JUL 2005

DOI: 10.1002/047147844X.wq296

Water Encyclopedia

Water Encyclopedia

How to Cite

Mukherji, S. 2005. Development Validation and Analysis of Salmonella Mutagenicity Test Methods. Water Encyclopedia. 2.

Author Information

  1. Indian Institute of Technology, Bombay, Centre for Environmental Science and Engineering (CESE), Powai, Mumbai, India

Publication History

  1. Published Online: 15 JUL 2005


Ames Assay is widely used for estimating mutagenicity in water samples that are extracted using columns packed with XAD resin. The test is conducted on plates using genetically engineered strains of Salmonella typhimurium, such as TA 98 and TA 100, where each is designed to indicate a specific mutation. Activation with rat liver microsomal fractions (S9-mix) is required for detecting the indirect acting mutagens. Mutagenicity is reflected by revertant count on test plates exceeding the spontaneous mutation frequency. These revertant counts are characterized by large variances often exceeding the mean. The two-fold rule commonly used for interpreting mutagenicity may yield a false interpretation depending on the strain-specific spontaneous reversion frequency. A dose response relationship may be established based on the initial linear region; however, parameter estimation is best performed using software specifically developed for this test. The slope is representative of the combined effect of mutagenicity and toxicity.


  • Ames Assay;
  • Salmonella typhimurium;
  • TA 97;
  • TA 98;
  • TA 100;
  • extraction;
  • S9;
  • metabolic activation;
  • two-fold rule