Cross-contamination is the transfer of harmful bacteria from one food, surface, or person to another. It is one of the leading causes of foodborne illness — and a guaranteed exam topic.
How cross-contamination happens
It usually happens when raw food (like raw chicken) touches ready-to-eat food, or when the same unwashed hands, cutting boards, or utensils are used for both.
7 ways to prevent cross-contamination
- Separate raw and ready-to-eat food at every step.
- Store food by final cooking temperature. Top to bottom: ready-to-eat food, seafood (145°F), whole cuts of beef/pork (145°F), ground meat (155°F), then poultry (165°F) on the bottom.
- Use color-coded cutting boards and separate equipment for raw meats.
- Wash your hands thoroughly between tasks.
- Clean and sanitize surfaces and utensils after contact with raw food.
- Don’t let raw food drip onto other foods in storage.
- Avoid bare-hand contact with ready-to-eat food — use gloves or utensils.
On your exam: the storage order question is the classic one — poultry always goes on the bottom shelf because it has the highest required cooking temperature.
Frequently asked questions
What is cross-contamination?
The transfer of pathogens from one food, surface, person, or piece of equipment to another — often from raw food to ready-to-eat food.
Why is raw poultry stored on the bottom shelf?
Because it has the highest minimum cooking temperature (165°F), storing it lowest prevents its juices from dripping onto foods cooked to lower temperatures.
Ready to test yourself? Take our free food handler practice test (instant answers and explanations), or review the full food handler study guide.