Persistent organic pollutants (POPs) are some of the most dangerous organic (carbon-based) compounds released into the environment by humans. These compounds have four key characteristics in common:- POPs are toxic causing adverse health effects (birth defects, damage to immune and respiratory system, and critical organs);- environmentally persistent, they resist breakdown by natural processes, and, in some cases, remain in the environment for decades;- hydrophobic but they are soluble in fatty tissue, which makes them bioavailable to mammals;- semi-volatile compounds and thus are capable to travel great distances through cycles of evaporation and atmospheric cycling and deposition (referred to as the “grasshopper effect”. The aim of the project is to investigate feed processing, focusing on drying procedures and their impact on the level of PCDD/Fs, dl-PCB and marker PCBs.