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Eggs are compulsorily inspected in the United States for hygiene, health and safety purposes. However, classification or grading to evaluate its quality is voluntary. If an egg producer wants to classify or grade them, they must pay for the service. The grades for the eggs in descending order are AA, A and B. The evaluation is based on the condition of the shell or exterior of the egg and the quality of its interior. They are then grouped according to size.

Shell Evaluation 

Eggshells are inspected for cleanliness, texture, shape, and freedom from cracks. To assess whether the shell is intact, small tap probes are used multiple times to record the sound they make when tapped. A high-pitched or high-pitched sound indicates that the shell is intact, while a thumping or “bang” sound indicates that it is cracked. Grade AA and A eggs have clean shells. While grade B is given to eggs with small spots.

Interior Assessment

In the past, eggs were placed in front of a candle to illuminate their interior for inspection. Currently, the egg is turned over a high-intensity light for inspection. In this process known as candling, the size of the air chamber, the proportion and quality of the white, as well as the firmness of the yolk are evaluated. The air chamber is an empty space between the white and the shell, located in the largest part at the end of the egg. Small air chambers are preferred.

Grade AA eggs have tall, round yolks and thick whites. Grade A eggs have “reasonably” firm whites, while Grade B eggs have thin whites and flattened yolks. Grade B eggs are processed into liquid, frozen or powdered products. Grade A eggs are the most sold, according to the United States Department of Agriculture.

Size

After grading based on observations made when evaluating the exterior and interior, the eggs are classified by size. In this particular, the size of the egg is a characteristic independent of the grade. Computer-controlled scales are used to weigh the eggs and sort them according to the minimum weight per dozen. Most recipes that include eggs are calculated based on large eggs. The egg sizes with their respective weights per dozen in the United States are as follows:

• Jumbo 30 ounces 
• Extra large 27 ounces 
• Large 24 ounces 
• Medium 21 ounces
• Small 18 ounces
• Pee Wee 15 ounces

Inspections

The United States Department of Agriculture and the United States Food and Drug Administration share federal regulatory responsibility for egg safety. These agencies conduct periodic inspections of business premises, facilities, inventories, operations, transportation vehicles, and records of egg handlers. They also inspect the records of all persons involved in the business of transporting, shipping or receiving eggs. State departments of agriculture and health oversee compliance with federal and state requirements. 

Carmen M. Pérez Velázquez