Paying attention to the source of the fish (looking for Pacific Pollack from sustainable stocks).

Critical Evaluation of the 2022 Öko-Test Results for Frozen Fish Sticks

Despite being the market leader, Iglo's classic fish sticks received a "Poor" ( Mangelhaft ) rating. The primary reasons were high levels of 3-MCPD and MOSH contamination. Rewe (Beste Wahl):

The investigation focused on several critical pillars: ingredients, pollutants, and the sustainability of the fishing practices used. The most alarming discovery was the presence of harmful substances in nearly half of the products tested.