What Can and Can't Go In The Fridge Door

• Don’t put eggs in the refrigerator door.  The temperature fluctuates there when the door is opened.  
• The door is a fine place for pasteurized fruit juices, olive oil, re-corked white wine, and condiments such as mustard and ketchup.
• Butter can  be stored in the door  because it has a very high  fat content  (80%) and low  water content (20%), which inhibits microbial growth

 
Sources:
Susan Brewer, Ph.D,, University of Illinois, Department of Food Science and Human Nutrition
eHow: How to Do Just About Everything  “How to Store Fruit in a Refrigerator”
USDA Fact Sheets Safe Food Handling   Refrigeration and Food Safety
USDA Factsheet: “Molds on Food”
University of Hawaii and USDA factsheet: “Store it. Don’t Ignore it!”
USDA Handbook: “Kitchen Companion”
The Today show website: “Fridge Findings: Learn Where to Store your Food” (2006)
Brewer, M.S. and Chapman-Novakofski, K. 2006.  “Meat Safety for the Consumer,” University of Illinois Extension