Kashrut Instructions (Courtesy of OU Kosher)
BLUEBERRIES:
INFESTATION: Cultivated blueberries, the type most commonly found in the supermarket, are generally insect-free. Still they should be placed in a strainer or colander and washed thoroughly under running water. Wild uncultivated blueberries, typically found in mountainous areas, require special inspection due to the prevalence of the ‘blueberry maggot’ (worm). Each berry should be individually inspected for holes or other indications of worms. INSPECTION: Cultivated blueberries should be placed in a strainer or colander and washed thoroughly under running water.
Wild blueberries must be carefully examined after washing. Spread them on a white cloth or a sheet of freezer paper and look for holes or other indications of worms.
Frozen Blueberries: Frozen Blueberries and other frozen fruits may be eaten with any washing or inspection, with the exception of frozen raspberries, blackberries, and strawberries which tend to be heavily infested.