Egg safety: USDA storage recommendations and freshness testing

To prevent foodborne illnesses such as Salmonella, the USDA’s Food Safety and Inspection Service (FSIS) recommends refrigerating eggs as soon as possible after purchase. Eggs should be stored at temperatures of 40°F (4.4°C) or below. For optimal safety, they should be kept in their original carton on an interior refrigerator shelf rather than in the door, as the door is subject to frequent temperature fluctuations.

Regarding freshness, a common method to identify old eggs involves a water test. According to advice shared by the late nutrition expert Frank Suárez, an egg that floats when submerged in a glass of water is likely old and should be discarded. This occurs because the air chamber inside the egg expands as it loses moisture over time, reducing its density. A fresh egg will sink to the bottom, while one that stands upright or tilts indicates it is several days old.