Impact of atmospheric cold plasma on microbiological quality, toxicological safety, physicochemical transformation of freshly pressed celery juice

Celery ( Apium graveolens L .) stalk juice is rich in chlorophyll, polyphenols, and other bioactive compounds, but its high perishability and susceptibility to microbial spoilage limit shelf life and consumer acceptance. Conventional thermal preservation improves safety but may reduce the content of heat-sensitive nutrients, creating a need for effective non-thermal alternatives. This study investigated atmospheric cold plasma (CP) as a mild preservation technology for freshly pressed celery juice, a matrix that remains poorly explored in plasma research. Integrated microbiological, toxicological, physicochemical, colloidal, structural, and compositional analyses were used to link CP-induced reactive oxygen and nitrogen species formation with microbial inactivation, particle stabilization, and retention of bioactive compounds. After 72 h of refrigerated storage, CP treatment reduced total aerobic microorganisms from 6.79 to 4.27 log10 CFU/ml (10 min) and 3.38 log10 CFU/ml (20 min), while yeasts and molds decreased from 6.77 to 3.32 and 2.20 log10 CFU/ml, respectively. A 10 min treatment provided the highest chlorophyll retention (12.05 µg/g), increased total polyphenols to 8.59 mg/100 ml, improved colloidal stability, and caused no adverse effects in the Danio rerio model. These findings identify CP as a promising non-thermal technology for producing safe, minimally processed vegetable beverages with preserved nutritional quality.