Gevina - Whey
QUESTION: Is whey subject to the restriction of Gevinas Akum?
ANSWER: No. It is clear from Teshuvos Chasam Sofer YD 79 that the restriction of Gevinas Akum was declared only on actual cheese which coagulates due to the addition of rennet. Whey, however, is merely the components of milk which did not form into cheese. Since whey is not formed by the rennet, but rather is just the residual milk, it is not subject to the prohibition of Gevinas Akum.
Nonetheless, whey requires very tight kosher supervision, due to numerous concerns, such as added non-kosher ingredients, the potential for it being cooked together with gevinas akum, and the shared hot use of non-kosher processing equipment in the whey facility. Also, since whey is usually sold as a powder, the dryer used to turn the liquid whey into powder must be kosher as well.
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