Josephine "Ann" Harris died hours after the president stopped by her western Pennsylvania diner. You'll be relieved to learn that the media was on it. From the post-death press gaggle between Jay Carney and the White House press corps:
CARNEY: Ann and her family are in our thoughts and prayers.
Q: Is there any concern that the President was in danger of having been food-poisoned or anything like that?
CARNEY: No. No.
Q: I mean, somebody dies in a restaurant where the President was --
CARNEY: She wasn’t even in the restaurant. She met with him outside -- she drove up to the restaurant. But, no, there was never -- I mean, obviously you can address questions about the President's security to the Secret Service, but, no, that was not a concern here. Based on the press reports, I believe it was a heart attack.
Some rudimentary googling reveals no follow-up stories on whether the Secret Service is investigating the president's exposure to food that didn't kill anyone.