Household Cooking Reshapes the Fate of Antibiotic Residues in Fish Alongside Changes in Tissue Water State and Microstructure

Household cooking reshapes antibiotic exposure from fish not merely by reducing parent residues, but by redistributing and transforming mixtures ultimately consumed. Here, 60 antibiotics were surveyed in 10 commercial aquatic products, and snakehead fish ( Channa argus ) was selected as a model to compare boiling, steaming, and air frying. All treatments reduced parent antibiotic residues in muscle, with boiling yielding the lowest retention (18.42 ± 0.41%). During boiling, muscle-associated parent antibiotics decreased by 83.38 ± 1.04%, but only 13.70 ± 2.53% of this loss was recovered in broth. Boiling also caused the greatest loss of immobilized water and tissue fragmentation, while moist heating generated a tightly associated water fraction during tissue restructuring. Nontarget screening tentatively assigned 15 enrofloxacin transformation products and revealed treatment-dependent profiles and prediction-weighted signals. These findings indicate that parent-compound depletion alone may overlook cooking-induced partitioning, broth coconsumption, and putative transformation products.