Methods to distinguish the quality of eggs

Distinguishing the quality of eggs can be comprehensively evaluated through methods such as observing appearance, shaking and listening to sound, water float testing, light penetration testing, and olfactory judgment.

1. Observe the appearance

Fresh egg shells are rough and shiny, with even powdery substances adhering to the surface. Rotten eggs may have cracks, mold spots, or obvious stains, and the shiny or sticky shell is often due to prolonged storage. Pay attention to whether the eggshell is intact during inspection, as damaged eggs are more likely to be contaminated by bacteria.

2. Shake and listen

Hold the egg and gently shake it, the fresh egg mixture is thick and almost silent. If you hear obvious water sound, it indicates that the air chamber has expanded or the protein has become diluted, and the freshness has decreased. But this method needs to be combined with other tests, and a single shaking may result in misjudgment.

3. Water Float Test

Place the egg in clean water, sink horizontally to the bottom for freshness, and stand upright or float to indicate an enlarged air chamber. Eggs with an air chamber larger than 9 millimeters may be stored for more than three weeks. During testing, the water temperature should be close to room temperature to avoid cold water causing eggshell shrinkage and affecting the results.

4. Light transmittance test

In a dark room, the eggs are irradiated with strong light. Fresh eggs appear light red and the chamber is less than 5 millimeters, with a visible shadow of the fixed yolk. If there is turbidity, blood streaks, or moving black spots, it has deteriorated. This method can detect internal changes that are not visible to the naked eye.

5. Olfactory judgment

Smell the eggs after beating, and fresh eggs only have a slight fishy smell. The smell of sulfur and decay indicates protein breakdown and should be discarded immediately. Before cooking, it is necessary to conduct a final olfactory confirmation, as some spoiled eggs may have no abnormalities in appearance. When storing eggs, they should be kept dry and ventilated, and the temperature should be controlled at 4-7 degrees Celsius to extend the shelf life. When purchasing, choose a legitimate channel and pay attention to the production date. It is recommended to heat thoroughly before cooking and avoid consuming soft boiled eggs or raw egg products. If the egg white is found to be abnormally thin, the yolk is prone to scattering, or pink fluorescence appears, it may be infected with Salmonella and should be stopped from consumption. Regularly check the inventory of the refrigerator, and handle eggs that have exceeded their shelf life with caution even if they pass the inspection.