The present invention relates to a method for testing oral malodor, in particular oral malodor from onion and garlic. Described herein are methods for testing the efficacy of an oral care composition to reduce oral malodor, the method comprising the steps of: a) cleaning at least a part of the oral cavity with an oral care composition; b) testing a first sample of exhaled breath from the cleaned oral cavity to provide a first test result representing a first amount of at least one oral malodor component detected in the exhaled breath; c) exposing the oral cavity to an oral malodor material including or capable of forming the at least one oral malodor component; and d) testing a second sample of exhaled breath from the oral cavity to provide a second test result representing a second amount of the at least one oral malodor component detected in the exhaled breath.

Disclosed herein are methods for determining the amount or activity of one or more luciferases and methods for measuring the luminescent signal generated by one or more luciferases in a sample, the methods comprising incubating the sample with a reactive substrate(s) of the luciferase(s) to be analysed and a reducing agent to inactivate a first luciferase, wherein the first luciferase, in its native form, is a secreted luciferase.

Method for determining volatile thio-ether compounds in offensive odorous sediment including: pre-treating a sediment sample, extracting volatile thio-ether compounds, separating and purifying the extraction supernatant in a solid phase extraction column, eluting with ethyl acetate, and finally collecting the eluent, which is then concentrated and used for determination by gas chromatography.

Method for determining volatile thio-ether compounds in offensive odorous sediment including: pre-treating a sediment sample, extracting volatile thio-ether compounds, separating and purifying the extraction supernatant in a solid phase extraction column, eluting with ethyl acetate, and finally collecting the eluent, which is then concentrated and used for determination by gas chromatography.

Disclosed herein are methods for determining the amount or activity of one or more luciferases and methods for measuring the luminescent signal generated by one or more luciferases in a sample, the methods comprising incubating the sample with a reactive substrate(s) of the luciferase(s) to be analyzed and a reducing agent to inactivate a first luciferase, wherein the first luciferase, in its native form, is a secreted luciferase.