Army spokesman Lt. Col. Christopher Garver said the investigation has been going on "for almost two months" at Fort Jackson outside Columbia. It wasn't clear who made the allegations or whether any soldiers had been sickened.
Garver said he could not release any specifics of the investigation by the Army's Criminal Investigative Service to protect its integrity.
"I can say that, according to CID spokespersons, they have not found any credible information to substantiate the allegations," Garver, who's based at the Pentagon, said in an e-mail.
He said he is unaware of any arrests made in the investigation.
The investigation was first reported by Fox News.
Army spokesmen from Fort Jackson didn't return repeated phone calls and e-mails seeking further comment.
Fort Jackson puts more than 50,000 men and women through entry-level and advanced training courses every year. Its food service spans an array of some 13 dining halls and about 40,000 hot meals are served on the base daily.