This is a good question fishtrap. Unfortunately I can't provide an ideal answer. If you have a smaller tank designated as a quarantine tank, then I'd put them in there for 10 days to 2 weeks...just to observe for any signs of problems.
With shrimp in the tank alone, it might be difficult to tell whether or not they might be carrying anything that may be harmful to fish in your larger tank. If, on the other hand, they are quarantined with other fish that have been in there for a while, then the fish's reactions over a week to two week period ought to tell you whether or not they're safe to put in your larger tank.
Sorry...not the best answer is it? Maybe someone else could chime in and suggest something.
Whatever you do, as I'm sure you already know---be sure you DO NOT dump the LFS water into any of your tanks (whether it be a quarantine tank or not) when letting those shrimp out of the bag(s)!
Big Vine