There are many variables. Your age, general health, and how much contaminated food you ate are all factors. The most common symptoms are diarrhea, nausea, vomiting, and abdominal pain, but you don't necessarily get all the symptoms. At-risk people can become very ill and can even die from foodborne illness because their immune systems are less able to fight off the bacteria.
Source: Excerpted from FDA/CFSAN Food Safety A to Z Reference Guide, September 2001