Egg grading is an important quality control process used to evaluate the freshness, cleanliness, and internal condition of eggs before they reach consumers. In the past, eggs were inspected using candlelight. Today, this process—known as egg candling—uses high-intensity light to examine the internal quality of eggs.

On July 20, 2020, the United States Department of Agriculture (USDA) established official guidelines for egg grading under the U.S. Standards for the Quality of Individual Shell Eggs. These standards classify eggs into different grades based on shell condition, air cell size, yolk position, and albumen quality.

Grade AA Eggs (Highest Quality Eggs)

Grade AA eggs represent the highest quality available in the market. These eggs are typically preferred for retail consumption due to their superior appearance and freshness.

• Shell: Clean, unbroken, and normal shape
• Air cell: Not more than 1/8 inch deep
• Yolk: Centered with a slight outline and no defects
• White (albumen): Firm, clear, and thick

Grade A Eggs

Grade A eggs are also high quality and commonly sold in supermarkets. While slightly lower than Grade AA, they remain fresh and suitable for consumption.

• Shell: Clean and unbroken
• Air cell: Not more than 3/16 inch deep
• Yolk: Fairly centered with a well-defined outline
• White: Clean, reasonably firm, may show slight thinning

Grade A eggs may sometimes contain trace amounts of processing oil on the shell surface but remain safe and high quality.

Grade B Eggs

Grade B eggs are still edible and safe but are of lower quality compared to Grade AA and A eggs. These are often used in processed egg products.

• Shell: May show moderate stains
• Localized stains: Not more than 1/8 inch in diameter
• Scattered stains: Not more than 1/16 of shell surface
• Yolk: Visible outline, may be slightly weaker
• White: Thin, watery, but still clear

Eggs with heavy stains or adhering dirt are not classified as Grade B.

Dirty Eggs (Rejected for Consumption)

Dirty eggs are considered inedible under USDA standards, even if the shell is not cracked. These eggs fail hygiene and quality thresholds.

• Stains exceed 1/8 inch in diameter
• Localized stains cover more than 1/32 of shell surface
• Scattered stains cover more than 1/16 of shell surface
• Dirt deposits are 1 mm or thicker

Check Eggs (Cracked but Unbroken Membrane)

A “check” egg has a cracked shell but the internal membrane remains intact, preventing leakage. Although the egg content is still contained, it is not suitable for retail sale or human consumption under standard grading systems.

Leaker Eggs (Broken and Exposed Contents)

Leaker eggs are eggs with cracked shells and visible leakage of internal contents. Due to contamination risk and exposure, these eggs are considered unsafe and unfit for consumption.

Conclusion: Why Egg Grading Matters

Understanding egg grades helps consumers, poultry farmers, and retailers identify quality, freshness, and safety. From Grade AA eggs to defective classifications like dirty, check, and leaker eggs, the USDA grading system ensures consistency and food safety standards across the poultry industry.