Stadium food is a vital part of the game day experience for many sports fans, but what if some of those foods could make you sick? This story originally ran in 2010. (9:44)

NEW YORK -- Philadelphia Phillies manager Ryne Sandberg and New York Mets first baseman Lucas Duda both came down with food poisoning over the weekend at Citi Field, and both said Tuesday that they believe a hamburger from Shake Shack was the cause.

Sandberg told reporters in Philadelphia that he lost 6 pounds in two days.

"A couple of coaches took a bite and didn't like what they saw and threw the rest away," Sandberg said. "I was in a rush so I ended up putting it away.

"I had one piece of toast in two days, and I'm feeling fine about that. I don't want anything in my stomach."

Duda was hospitalized Friday afternoon and later blamed an undercooked hamburger. He confirmed Tuesday at Yankee Stadium that the burger also came from Shake Shack.

But a Mets spokesman insisted the hamburger Duda cited came from another Shake Shack location besides Citi Field.

Duda missed Friday night's game against the Phillie s but was able to return to the Mets' lineup Saturday and has played every game since then.

A Mets official said the team is investigating the matter.

"We've served thousands of guests at our Citi Field Shack over the past week, and this is the first we've heard of any issue whatsoever," said Greg Waters, senior manager for marketing and communications with Shake Shack. "We take every guest concern of any sort seriously, and as such reached out to Ryne Sandberg to get more information since we have not heard from him. We stand by our food quality 100 percent."