Ponderosa restaurant was years ahead of the terrorists, naturally poisoning their customers since 1981. Seriously, you'd look at the salad dressing and see twelve other pieces of food that other customers dropped in it...
Al Qaeda group contemplated poisoning food in U.S., officials say
If something like this occurred, it would not be first time it happened in the US. In 1984, a bizarre cult in Oregon tried to poison a whole town in an effort to win local elections. 750 people were poisoned and all of their candidates still lost....
1984: Rajneesh Cult Attacks Local Salad Bar
THE DALLES, Ore. (AP) - In 1984, followers of the Indian guru Bhagwan Shree Rajneesh spiked salad bars at 10 restaurants in town with salmonella and sickened about 750 people.
The cult members had hoped to incapacitate so many voters that their own candidates in the county elections would win. The scheme failed, but the episode spread fear in The Dalles and drained the town's economy.