Fish sauce classified under 2103902000 is subject to FDA's seafood HACCP regulation (21 CFR Part 123), which requires that the foreign processor operate under a HACCP plan addressing hazards specific to fermented fish products, including histamine formation. Importers must verify that their supplier has an adequate HACCP program and should be prepared for FDA sampling and examination at entry, as fish sauce is a product with a history of FDA import alerts related to histamine levels.

The distinction among these mixed condiment and seasoning lines turns on US Chapter 21 notes and Chapter 17 sugar content thresholds. Line 2103907400 applies to blends meeting the definition in US Note 8(a) to Chapter 17 (typically high-sugar blends used as syrup bases), while 2103907800 covers blends subject to Note 3 of Chapter 21, and 2103908000 is the general residual. Importers should review the applicable chapter notes carefully and consult a licensed customs broker, as misclassification between these lines is common and can affect duty liability.