Sanitation of plastic bottles using ozonated water

Abstract

Ozone is a powerful sanitizer that does not generate hazardous residues. Thereby it can be used as an alternative for traditional chemical sanitizers on surfaces, vegetables and packaging decontamination. This study aimed to characterize the ozone decay kinetic in water and to evaluate the ozonated water efficacy for decontamination of plastic bottles. The ozone concentration decay was determined by ozone measurement in water after ozone generation. The ozone efficacy was studied using PET bottles contaminated with spores of Bacillus subtilis and then washed with ozonated water at concentrations of 1 and 4 mg.L-1 for 3, 7 and 10 minutes. The maximum ozone concentration solvated in water was 4 mg.L-1 and the ozone decays was described by an exponential equation. The half-life of the ozone in water was calculated as 9.2 minutes. Based on this data, the times for bottle treatments were chosen. The results of B. subtillis spores reduction showed that ozonated water at 1 mg.L-1 was not effective. On the contrary, around 2 decimal reductions were reached by applying ozonated water at 4 mg.L-1 for 3-10 minutes. The results showed that ozonated water is a potential sanitation to be applied for bottle surface decontamination, but the process efficacy is dependent on the ozone concentration, temperature and time of exposure.