Food borne illnesses can cause the following symptoms:

NAUSEA
The urge to vomit, or bring up the stomach contents through the mouth.

CONSTIPATION
Difficulty having bowel movements because they are hard or dry.

FEVER
A rise in body temperature above normal. "Normal" depends on how you measure your child's body temperature. If you measure by rectum (bum) or by ear, fever means a temperature over 38°C (100.4°F). If you measure by mouth, fever means a temperature over 37.5°C (99.5°F). If you measure in the armpit, fever means a temperature over 37.3°C (99.1°F).