the more the shrimp get thawed and refrozen the more their cell structure breaks down, leaking nutritional oils out of the shrimps body, and breaking them down, that said almost every manufacture of mixed blend frozen foods have thawed, blended and refrozen the product and then shipped it to the consumers. I have thawed and repackaged frozen mysis relicta many times with little adverse affects... I prefer to mix it when freshly harvested, but that is not always possible...