"It is a rumor," he said.
Chuck Krause, who is investigating the incident for OEHS, said that as of Monday afternoon there was "no clinical evidence" that food poisoning was to blame for the illnesses.
He pointed out that "this is the time of year when flus can hit."
Krause said officials "weren't sure of the numbers" of people who had reported symptoms, which included diarrhea, over the weekend.
According to Condenzio, only four or five of the 59 people at the meal reported symptoms.
Estimates by students who ate at Hillel on Saturday, however, ranged from 10 to 40 afflicted.
Rosenthal said UHS would conduct an epidemiological investigation, which may include isolating the suspect food, culturing available left overs and analyzing samples from people who are still sick.
Students from Boston University visited Hillel this weekend, and joined in Saturday's lunch.
The source of the illnesses is not known at this time. UHS officials urge any student who ate at Hillel Saturday and who is experiencing symptoms to contact UHS or the OEHS.