Ferrous sulfate/carboxymethyl chitosan agar-based film triggers ferroptosis in Pseudomonas aeruginosa planktonic and biofilm cells for antibacterial preservation of fruits and vegetables

The ferrous sulfate (FeSO 4 )-based mechanism causing ferroptosis-like death in Pseudomonas aeruginosa was investigated. FeSO 4 triggered ferroptosis in P. aeruginosa planktonic cells, decreased the ratio of glutathione to oxidized glutathione, and resulted in the increase of reactive oxygen species and lipid peroxidation, damaging the integrity of the cell membrane. In addition, FeSO 4 prevented P. aeruginosa from forming biofilms on the surface of stainless steel, glass, and high-density polyethylene. Transcriptome analyses indicated that there were 412 up-regulated genes and 782 down-regulated genes following FeSO 4 treatment. FeSO 4 increased the cross-linking density of a carboxymethyl chitosan (CMCS) agar-based film, reducing its water solubility, swelling degree, water vapor permeability, and oxygen permeability. Finally, FeSO 4 @CMCS agar-based film showed potential antibacterial ability against the growth of P. aeruginosa in grapes, purple kale, and cherry tomatoes during storage.