0404.90 - Other:

This HTS category, 0404.90, encompasses "Other" products derived from milk constituents that are not specifically classified under the preceding subheadings. This includes a broad range of dairy-based items that consist of natural milk constituents but do not fit the precise definitions of whey or modified whey. These products may be concentrated or have added sugar or other sweetening matter, provided they are not elsewhere specified in Chapter 4 of the Harmonized Tariff Schedule.

Distinguishing this category from its sibling, 0404.10 (Whey and modified whey), is crucial. While both deal with products derived from milk constituents, 0404.90 is for those that are not whey or modified whey. This implies that the processing or the resulting product's composition differs significantly from that of typical whey. The key differentiator lies in whether the product's defining characteristic is its whey content or if it represents a distinct category of milk-derived substances.

Within this "Other" category, further subdivisions exist to address specific types of milk-derived products. The primary subcategory is "Milk protein concentrates," indicating a portion of this heading is dedicated to products where the protein fraction of milk is specifically concentrated. The existence of an additional "Other" subcategory suggests that there are further, more granular classifications of milk-derived products that fall under 0404.90 but are not milk protein concentrates, requiring careful examination of their specific composition and intended use for accurate classification.