3.1 Understanding Cross-Contamination

Cross-contamination is the transfer of harmful microorganisms or allergens from one surface or food to another. It is a leading cause of foodborne illness outbreaks.

Types of Cross-Contamination

1. Direct Cross-Contamination Physical contact between raw and ready-to-eat foods:

• Raw chicken touching salad greens
• Blood from raw meat dripping onto cooked food
• Placing ready-to-eat food on a contaminated surface

2. Indirect Cross-Contamination Transfer through an intermediate object:

• Using the same cutting board for raw chicken and vegetables
• Using the same knife without cleaning
• Touching raw meat then touching other items without washing hands
• Using contaminated towels or sponges

How to Prevent Cross-Contamination

Storage Order in Refrigerator

From TOP to BOTTOM, store foods by their cooking temperature (lowest cooking temp on top):

1. Top shelf: Ready-to-eat foods, prepared foods
2. Second shelf: Whole fish, whole cuts of beef/pork (145°F)
3. Third shelf: Ground meats, ground fish (155°F)
4. Bottom shelf: Raw poultry (165°F)

Memory Tip: "Ready-to-eat on top, poultry on bottom" - this prevents raw meat juices from dripping onto foods that won't be cooked.

Why This Order?

If raw chicken (requires 165°F) drips onto a steak (requires 145°F), the steak won't be cooked to a high enough temperature to kill chicken bacteria. Ready-to-eat foods are at the greatest risk because they won't be cooked at all.