Does Cottage cheese, lowfat density change after the container has been opened for several days?

Marginally. Butterfat can separate or bloom, but measured weight per cup/mL stays within 1 % as long as the product is within its use-by date.

Can I swap whole Cottage cheese, lowfat for skim at the same gram weight?

For mass yes, but fat content changes flavor, browning and texture. In baking, match the variant the recipe expects rather than the raw gram count.

By Fidamen-Chefsolver Team | Reviewed by Ugo Candido

Lowfat cottage cheese is creamy-curd, mild, and protein-rich with reduced fat.

Ingredient

Eat on toast, in bowls, blended into dips, or swap for ricotta in recipes.

Does Cottage cheese, lowfat density change after the container has been opened for several days?: Marginally. Butterfat can separate or bloom, but measured weight per cup/mL stays within 1 % as long as the product is within its use-by date.
Can I swap whole Cottage cheese, lowfat for skim at the same gram weight?: For mass yes, but fat content changes flavor, browning and texture. In baking, match the variant the recipe expects rather than the raw gram count.