Whether blueberries are mechanically or manually harvested, every effort should be made to keep the percentage of defective fruit to an absolute minimum. Seriously defective fruit may include those with insect damage, broken skin, decay or mold, attached stems, fruit remaining in clusters, and fruit that is overripe, underripe, shriveled, or off-color. U.S. Number 1 is the only specified grade for harvested blueberries. Blueberries grading U.S. Number 1 may have no more than 1 percent serious defects and no more than 13 percent total defects. However, in practice and especially with fresh-market blueberries buyers may require less than 5 percent total defective fruit.
Most buyers prefer large fruit over small fruit if they are of good quality.
Within the U.S. Number 1 classification there are four size classifications, as listed in Table 1. For the complete USDA standard classifications for blueberries, refer to 46 FR 63203 or the latest revision. Packaged and palletized blueberries being received at a central cooling and shipping facility. Cooling At warm field temperatures, harvested blueberries are extremely perishable and decline rapidly in quality. Visible signs of decay organisms can develop on warm, wet blueberries in less than 12 hours.