IIRC, the caffeine in black teas inhibits the growth of bacteria, so a sanitary package of loose tea (such as foil packaging) should be clean.
Just to be safe though, you could boil the tea in a volume of water for approx. 10 minutes to sanitize, chill in a sanitary container, and pour the whole slurry into the brew. I can't comment on what that will do for flavor though. Teas steeped hot for more than a few minutes sometimes get bitter, but in a 5 gal batch, it will probably be negligible against the hops.
I guess it depends on what you are looking to accomplish with a tea addition. Are you looking for flavor, tannins, or something else? Maybe there is an alternative to adding the tea leaves directly to the secondary, such as just adding the steeped water?