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Ozone Disinfection in Bottled Water: A Model for the Bottled Water Industry
Abstract
Ozone is a powerful disinfectant that is widely used in the bottled water (BW) industry. Primary ozone disinfection occurs in a reaction tank with specific contact time, however, residual ozone in the water that is bottled may still possess disinfection activity. The purpose of this study was to evaluate the efficacy of residual ozone in reducing the populations of surrogate microorganisms for waterborne pathogens Escherichia coli (BAA-1427), Enterococcus faecalis (ATCC 19433) and Burkholderia cepacia (ATCC 25416), adenovirus type 41 (Ad41), and foodborne pathogens E. coli O157:H7, non-O157 serogroup, and Salmonella Typhimurium. The effect of water pH and total dissolved solids (TDS) on the disinfection process was evaluated. A pilot scale ozone delivery system and filler were assembled to allow filling of 0.5 L polyethylene terephthalate (PET) plastic water bottles with ozonated (0.1, 0.2, 0.3 and 0.4 mg/L) water. Ozonated water was inoculated with microorganisms to attain ca. 6.0 log10 and 4.0 log10 CFU/mL and microbial populations were determined after 5, 30, 60 and 180 min at 25°C. Samples (100 mL) were filtered through Neogen NEO-GRID membrane filters and placed on tryptic soy agar, incubated for 48 h at 37°C and enumerated. Ozone dissipation in BW was measured with and without biological load (6.0 log10 CFU/mL) at 21.1 and 37.7 °C for 6 h. Greater reductions (P≤0.05) in E. faecalis (4.61 log10 vs. 3.68 log10 CFU/mL) and B. cepacia (5.24 log10 vs. 4.12 log10 CFU/mL) were observed at 0.4 vs 0.1 mg/L ozone in BW, respectively. Extension of storage time did not result greater reductions (P>0.05) in microbial populations. Faster ozone dissipation (P<0.05) was observed at 37.7 °C and dissipation rate increased with biological load. The residual ozone in BW (0.1 to 0.4 mg/L) can provide ≥ 4.0 log10 reductions in pathogen surrogates E. coli, E. faecalis and B. cepacia, the foodborne pathogens E. coli O157:H7, non-O157 serogroup, and Salmonella Typhimurium, and adenovirus type 41, providing an additional measure of microbiological safety in BW products.
Subject Area
Food Science|Health sciences|Public health
Recommended Citation
Schwaner, William Ryan, "Ozone Disinfection in Bottled Water: A Model for the Bottled Water Industry" (2023). ETD collection for University of Nebraska-Lincoln. AAI30814266.
https://digitalcommons.unl.edu/dissertations/AAI30814266