Design an experiment (including controls) to determine if a new kitchen chemical cleaner is ...

 The Ames test could be used to determine if the cleaner solution causes mutations in bacteria. An auxotrophic mutant strain (e.g., Salmonella enterica His-) containing a point mutation is most helpful for this test, so it can measurably revert in small populations of cells. A His-cell population exposed to various concentrations of the cleaner solution would then be put into agar plates lacking histidine, and the number of colonies that grew would represent cells that mutated back to wildtype (His +). An important control for the test is to plate an equal number of cells not exposed to the cleaner solution on to the same medium to calculate a baseline mutation rate of the cells when not exposed to the chemical cleaner. If there are significantly more His+ revertants that grew after exposure to the cleaner solution, then the chemical is mutagenic.

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