Short answer: TA means Total Activity. In honey testing it describes measured activity that can include both peroxide-related and non-peroxide components. A TA number is a grading result, not a methylglyoxal concentration and not a medical claim.
What Total Activity includes
Honey can exhibit activity arising from hydrogen peroxide and from non-peroxide factors. Total Activity is intended to express the combined laboratory result under the test method used. The exact report and product documentation remain the authoritative source for a particular batch.
TA is not MGO
MGO reports methylglyoxal concentration in milligrams per kilogram. TA reports an activity result. Although both appear as numbers on speciality honey, they do not share the same unit or meaning and should not be compared as if they were a single scale.
TA and NPA are also different
NPA is specifically non-peroxide activity—the portion remaining when peroxide-related activity is neutralised in testing. TA can include both parts. This is why a Jarrah TA rating should be read as stated rather than converted informally to a Manuka NPA figure.
How to shop using a TA label
Check the declared TA grade, batch or testing information where supplied, country of origin, net weight and seller. If a product page uses broader quality language, the exact grade should still be easy to identify and should not be replaced by unsupported health promises.
Sources and further reading
Information notice: This article provides general food and product information, not medical advice. Honey is not suitable for infants under 12 months; see Healthdirect's infant safety information.