We had gorgeous blackberries when they first came on and we have sprayed for Japanese beetles which seem to be under control. However, we now have quite a bit of white "bulbs" on the berries which makes them unsightly as well as some unuseable. *I used the term bulbs because I don't know what the individual parts of the berry is called.
Sussex County Delaware
The condition you describe is called white druplet. The individual sections on a raspberry or blackberry are called druplets. The most common cause of discoloration, including white color, is high UV light or sunlight. Often this disorder is associated with changes in weather from overcast to bright dry sunny weather. It is sometimes linked to insect damage from stink bugs too. I'm not sure if the Japanese beetle feeding may have played a role. Anyway, the disorder is physiological, and there are not microorganisms involved that would make you sick or alter the nutritional value of the berries. They may be a little drier, or not as sweet, but would still be usable.
Purdue University included this disorder in a post on their website: https://www.ppdl.purdue.edu/PPDL/weeklypics/9-6-10.html
Thank you for contacting Delaware Cooperative Extension,