The top 10 causes of food-borne illnesses include:
Failing to cool foods properly - Hot foods must be cooled down as quickly as possible. Place hot food in shallow pans or use an ice bath. Large items such as turkeys or roast must be sliced to aid in cooling, then placed in shallow pans.
Cross-contamination - The classic example of cross-contamination is preparing raw chicken on a cutting board and then, without washing and sanitizing, using the same board and knife to prepare salads.
Personal hygiene - Proper hand washing is the single most important means to prevent the spread of infection.
Improper reheating - Leftovers must be reheated rapidly to at least 165°F. Note: Steam tables are not designed for reheating leftovers.
Improper hot holding - Once cooked, hot foods must be kept at 140°F or above. (Cold foods must be kept at 40°F or below.)
Mixing raw foods with cooked foods - A good example of this practice would be adding raw eggs to already prepared eggs on a steam table. Also, do not add freshly made potato salad to a container of potato salad that is in use.
Food from unapproved sources - All food must be obtained from sources that comply with all laws relating to food and food labeling.
Improper Cleaning - Equipment and utensils must be washed, rinsed, and sanitized. Sanitized means the removal of harmful microorganisms (i.e. using bleach).
Over prepping - Preparing more food than necessary. It creates a storage problem that can lead to contamination.
Inadequate cooking - Foods must be cooked to the proper temperature. Use your stem thermometer (0°F-220°F) to insure that temperatures are being met.