Ames Test – OECD 471

The Ames test is an essential method in genetic toxicology. It allows for the evaluation of a substance's mutagenic potential, that is, its ability to cause point mutations in its genes. This test relies on the use of specific strains of Salmonella typhimurium that are deficient in histidine synthesis.

Used in the cosmetic, chemical, pharmaceutical, and food industries, the Ames test is a key step in assessing the safety of ingredients, whether natural or formulated substances. It is recommended by the OECD under guideline 471 and recognized in regulatory frameworks (REACH, CLP, etc.).

Test objective

• Detect reversible mutations (point mutations) caused by a substance
• Predicting carcinogenic or genotoxic potential
• Evaluate plant extracts, chemical compounds, cosmetic ingredients, or medications
• Meeting regulatory requirements for new product registration

Methodology

The test uses several bacterial strains of Salmonella typhimurium , which are unable to grow without histidine. In the presence of the substance to be tested, if colonies appear on a histidine-free medium, this means that mutations restore the ability to synthesize the substance – thus indicating mutagenic activity.

Two experimental conditions are systematically evaluated:

• Without metabolic activation (direct test on bacteria)
• With metabolic activation (S9 mix) to simulate human liver metabolism (as in the case of pro-mutagens)

The results are interpreted according to the number of reverting colonies compared to the control, with calculation of a mutation index.

Industrial applications

• Cosmetics: safety of active ingredients, raw materials
• Pharmaceuticals: screening of new molecules
• Fine chemicals: toxicological classification
• Plants / nutraceuticals: plant extracts, bioactive compounds
• Food industry: additives, contaminants

Why go through YesWeLab?

YesWeLab connects you with laboratories specializing in regulatory testing, accredited and experienced in performing the Ames test according to OECD 471. Our partners have all the standardized strains, metabolic activation systems (S9) and proven expertise in toxicological interpretation.

Through our digital platform, you benefit from centralized analysis management, personalized scientific support, and rapid processing of your requests. Since 2020, dozens of manufacturers have trusted us to ensure the safety of their products.

See also:

• Micronucleus test – OECD 487
• Genotoxicity test 
• HET-CAM Test