Before blueberries are packaged, they must be graded according to North Carolina and United States law. This is to keep damaged or infected fruit from making it to your plate at home. Blueberries are cleaned and inspected during the packing process. Inspectors take random samples of the berries and examine them closely to assure that quality standards are met. A No. 1 berry means that it is good and has passed the standards, anything else is rejected and would not be sold.
Inspectors look at blueberries for some basic requirements.
These are that the berries are similar, clean, well colored, not overripe, not crushed, split or leaking, and not wet. The berries would also be free from attached stems, mold, decay, insects or evidence of insects, mummified berries and clusters. Berries must also not be shriveled, have broken skins, scars or green berries. Once the USDA inspectors have determined that the blueberries are safe for eating, they are then packaged. Fresh berries are most commonly packaged in one-pint clamshells.