Total activity (TA)

Definition

A TA number expresses a honey's measured antibacterial activity in a laboratory assay as equivalent to a percentage solution of phenol. Unlike manuka's methylglyoxal activity, the activity being measured is the ordinary hydrogen peroxide mechanism that most honeys have — glucose oxidase added by the bees generates peroxide when the honey is diluted. Jarrah rates highly because of its particular enzyme activity and low glucose content.

Where the word gets used loosely

Peroxide activity is destroyed by catalase, an enzyme present in human tissue and blood, and it degrades with heat and storage — so a TA number measured on a sample in a laboratory predicts very little about what happens after swallowing. It is also not a compositional definition and says nothing about floral purity. Like MGO, it creates a number on a jar that a buyer cannot verify.

Honey records that discuss this

• Jarrah honeyDark, malty and caramelised, with a coffee-and-treacle depth and much less of the medicinal edge a comparably dark honey usually carries.