3501.10 - Casein:

This HTS category, 3501.10, specifically covers casein, a major protein found in milk. Casein is primarily obtained from skimmed cow's milk by acid or rennet precipitation. It is a versatile substance used in various industrial applications, including the production of plastics, adhesives, paints, and as a nutritional supplement in food products. The classification here focuses on the raw or processed casein itself, prior to further significant modifications or incorporation into more complex preparations.

While the broader heading 3501 encompasses casein, caseinates, and other casein derivatives, this subheading 3501.10 isolates pure casein. Its sibling category, 3501.90, covers "Other" products within the casein family, such as caseinates (salts of casein) and modified casein derivatives that have undergone chemical alterations or are presented in a form not specifically defined elsewhere. Therefore, 3501.10 is for the foundational protein substance, distinct from its more processed or derivative forms.

Within the 3501.10 category, further subdivisions exist to provide greater specificity. Subcategory 3501.10.10.00 designates "Milk protein concentrate," which often includes casein as a primary component, particularly when the concentrate has a high protein content derived from milk. The remaining "Other" subcategory, 3501.10.50.00, captures all other forms of casein that do not meet the specific criteria for milk protein concentrate, ensuring a comprehensive classification of casein itself.