My Tea Is Kosher

Recently, while getting a late-night cup of tea at an airport,* I happened to notice some labelling on the back of the foil teabag sleeve to the effect that this tea was kosher. It's turns out it's also halal, a term I'd not heard before, meaning roughly the Muslim equivalent of kosher.
So, now I'm mildly curious whether this applies to all types of tea (because the people who wrote the Pentuach and the Koran didn't know about tea and thus didn't forbid it), or to this particular brand (because of special preparation). Is there an explicit way to make tea that renders it kosher/halal, or is this an example of Bellairs' Law?
Further investigation definitely called for.

--JDR


*[Cleveland, between flights]

UPDATE (W.9/17-08): I found the foil sleeve for the teabag in question, which I'd set aside, and can now report that it was NUMI brand (Morning Rise Breakfast Blend, a black tea). At the bottom on the back are five icons signifying that it is certified Organic, certified Fair Trade, 'Kosher & Pareve', and 'Halal', and noting that the sachet itself (the actual teabag) is biodegradable. Although, as I understand it, the tea will only remain 'pareve' so long as you don't add milk or cream to it.
--JDR