You might be surprised to know how many instances of food poisoning are due to improper prep/storage of beverages.
Foodborne pathogens can survive in brewed tea, but for tea brewed at an appropriate temperature–with water hot enough to kill pathogens–the issue of safety is primarily one of storage conditions and ensuring the tea dispenser has been cleaned and disinfected before use.
Brewing iced tea at an appropriate temperature in a thoroughly cleaned urn and limiting the time held at room temperature before serving will minimize the risk of bacterial contamination.
* Iced tea should be brewed at 195 F for 3-5 minutes. * Iced tea should be stored for no longer than 8 hours.
* The tea brewer, storage dispenser, and faucet should be cleaned daily.
Cases where foodborne illness occur from beverages is almost always due to unclean/disinfected storage containers and holding the tea for long periods of time. I know of one establishment that never threw out tea at the end of the day. They just topped it off each day with new brew and I doubt that the storage container was cleaned/disinfected more than once or twice a month. I never did drink their tea.