To investigate the comprehensive effects of multiple factors including time, temperature, bacterial strains, initial contamination levels and types of packaged drinking water on the viability of Pseudomonas aeruginosa in packaged drinking water.

Different types of commercially available packaged drinking water samples were artificially contaminated with Pseudomonas aeruginosa strains from various sources at different levels.The concentration changes of Pseudomonas aeruginosa in packaged drinking water under different temperature conditions were continuously monitored using the membrane filtration method and plate count method, and the comprehensive effected of relevant factors on the viability of Pseudomonas aeruginosa in packaged drinking water were analyzed.

In natural mineral water for drinking, the trends of Pseudomonas aeruginosa concentration over time at different temperatures exhibited essential differences. When the initial contamination level was approximately 70 CFU/mL, at 23 ℃ and 30 ℃, the bacterial concentration increased exponentially from the 3rd to 4th day. At 30 °C, the concentration reached 10⁶ CFU/mL on the 3rd day. At 15 ℃, the proliferation was delayed until the 5th to 6th day, with the concentration reaching 10⁶ CFU/mL on the 9th day. In contrast, at 8 ℃, the bacterial concentration showed a continuous slow decline, although it remained detectable (3 CFU/mL) until the 12th day. In purified water for drinking and other drinking water, the concentration of Pseudomonas aeruginosa generally showed a decreasing trend at different temperatures, but the decay rates differed significantly. When the initial contamination level was approximately 70 CFU/mL, in purified water for drinking, Pseudomonas aeruginosa decayed fastest at 8 ℃ and 30 ℃, becoming undetectable (0 CFU/mL)on the 3rd day. At 15 ℃, the decay rate was the slowest, with the concentration falling below the detection limit on the 5th day. At 23 ℃, the decay rate was intermediated between the above two, with the concentration becoming undetectable on the 4th day. In other drinking water, at 30 ℃, Pseudomonas aeruginosa exhibited the fastest decay, becoming undetectable (0 CFU/mL) on the 3rd day. At 15 ℃ and 23 ℃, the decay rate was moderate, with the concentration falling below the detection limit on the 5th day. At 8 ℃, the decay rate was the slowest, with the concentration becoming undetectable on the 7th day. Under identical test conditions, including temperature and type of packaged drinking water, the effects of differences in strain and initial contamination level on the trends of Pseudomonas aeruginosa concentration were generally consistent.

The combined effects of factors including time, temperature and type of packaged drinking water on the viability of Pseudomonas aeruginosa are extremely significant.Nevertheless, despite differences in bacterial strains and initial contamination levels, the changing trends of Pseudomonas aeruginosa viability are generally consistent. The findings of this study will provide more scientific evidence for risk prevention and control in the production, processing, quality control and market consumption stages of packaged drinking water.