Legal Question in Consumer Law in Indiana

Of course you can sue them. They'd likely settle the case, but it would be more likely to be for little more than "nuisance value," primarily because those cases can be difficult to prove. Keeping the sushi does you little good unless you immediately had it analyzed. At trial, you'd have to introduce evidence that the roll was somehow contaminated. You could have brought it to the health department and complained. If others are complaining, then they might look into it, which would help your case.

It isn't that you can't prove the case, but they can be difficult.

Suggest you write them a letter complaining and offer to settle your claim. If they refuse, then consider having a lawyer get involved.