This study investigated the physicochemical characteristics and chemical safety of commercial wet cat foods marketed in Brazil. Twenty products labeled as beef, chicken and fish flavors were analyzed for proximate composition, pH, lipid and protein oxidation, biogenic amines, and essential and potentially toxic trace elements. Moisture ranged from 78.13% to 94.87%, and protein varied from 37.38% to 89.97% dry matter. Thiobarbituric acid reactive substances (TBARs) value reached 2.49 mg malondialdehyde (MDA)/kg dry matter, and carbonyl protein up to 0.81 nmoL/mg protein dry matter, indicating oxidative damage in part of the samples. Histamine, putrescine and cadaverine were detected on average levels of 7.5, 3.5 and 3.5 mg/kg wet matter, respectively, indicative for microbial activity and/or the use of raw materials of suboptimal quality. Trace element analysis revealed mercury concentration between 0.00 and 1.34 mg/kg, Cu (0.01 mg/kg) and Zn (45−50 mg/kg) were found in some samples (dry matter). The evidence of oxidation, biogenic amine and toxic elements in wet pet food, even within available international reference values, is a warning for chronic consumption by cats, a species with limited hepatic detoxification capacity. Overall, the findings highlight the need for strengthened quality assurance schemes and systematic surveillance on wet pet foods to better safeguard feline health.

Plastic pollution has become a global environmental issue, yet little is known about how plastics degrade and interact with microbes under polar conditions, especially upon entering the marine environment. Here, we report the first in situ time-series experiment investigating early microbial colonization and surface oxidation of virgin plastics in Antarctic coastal waters. Virgin pellets of polystyrene (PS), low-density polyethylene (LDPE), and polyethylene terephthalate (PET) were deployed in Potter Cove (King George/25 de Mayo Island) for 31 days. Biofilm communities were characterized using 16S rRNA amplicon sequencing, while polymer surface chemistry was assessed by Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR). Across all polymers, plastisphere assemblages were dominated by psychrophilic or psychrotolerant taxa. Plastic-associated communities showed consistent temporal changes over the 31-day exposure, with shifts in the relative abundance of taxa associated with different stages of biofilm development. Exposure time was a stronger determinant of community composition than polymer type. FTIR analyses revealed significant surface oxidation in PS and LDPE, particularly at days 21 and 31, with increases in hydroxyl, carbonyl, and carbon–oxygen indices. PET showed great variability and no consistent oxidative signals over the study period. The chemical shifts partially covaried with taxa associated with later sampling points, suggesting potential, but not yet conclusive, links between biofilm succession and polymer weathering. Our results provide some novel insights into the early dynamics of microbial colonization on plastic surfaces and polymer surface alteration in Antarctic waters, highlighting the importance of integrating microbial and chemical perspectives to understand plastic fate in polar ecosystems.