Modelling the Ozone-Based Treatments for Inactivation of Microorganisms

Abstract

The paper presents the development of a model for ozone treatment in a dynamic bed of different microorganisms (Bacillus subtilis, B. cereus, B. pumilus, Escherichia coli, Pseudomonas fluorescens, Aspergillus niger, Eupenicillium cinnamopurpureum) on a heterogeneous matrix (juniper berries, cardamom seeds) initially treated with numerous ozone doses during various contact times was studied. Taking into account various microorganism susceptibility to ozone, it was of great importance to develop a sufficiently effective ozone dose to preserve food products using different strains based on the microbial model. For this purpose, we have chosen the Weibull model to describe the survival curves of different microorganisms. Based on the results of microorganism survival modelling after ozone treatment and considering the least susceptible strains to ozone, we selected the critical ones. Among tested strains, those from genus Bacillus were recognized as the most critical strains. In particular, B. subtilis and B. pumilus possessed the highest resistance to ozone treatment because the time needed to achieve the lowest level of its survival was the longest (up to 17.04 min and 16.89 min for B. pumilus reduction on juniper berry and cardamom seed matrix, respectively). Ozone treatment allow inactivate microorganisms to achieving lower survival rates by ozone dose (20.0 g O3/m3 O2, with a flow rate of 0.4 L/min) and contact time (up to 20 min). The results demonstrated that a linear correlation between parameters p and k in Weibull distribution, providing an opportunity to calculate a fitted equation of the process.

Inactivation of Foodborne Bacteria Biofilms by Aqueous and Gaseous Ozone

“…The existence of a tail clearly indicates that, as in the case of attached cells, a portion of the microbial population is resistant to treatment, due to inherent or acquired resistances during ozonation treatment ( Valdramidis et al, 2012 ). This behavior related to ozonation treatments was also observed by other authors, although not for sessile microorganisms, i.e., in the form of biofilms ( Brodowska et al, 2017 ). The values of the D β parameter estimated by the Weibull model in this study indicate that the dynamic treatment was very effective, as it was able to inactivate 90% of the microbial population in the biofilms in a few seconds.…”

Effects of Gaseous Ozone on Microbiological Quality of Andean Blackberries (Rubus glaucus Benth)

“…Cells were used when a concentration of 10 9 CFU mL −1 was reached. Microbial concentration was determined according to the McFarland scale at 600 nm (OD600) [ 32 ]. An isolate of B. cinerea was cultured in a Petri dish on potato dextrose agar (PDA, Difco, Detroit, MI, USA).…”

Promising Intervention Approaches to Potentially Resolve Neuroinflammation And Steroid Hormones Alterations in Alzheimer’s Disease and Its Neuropsychiatric Symptoms

“…In bacteria, O 3 disrupts the integrity of the bacterial cell wall through oxidation of phospholipids and lipoproteins [ 181 , 182 ]. In fungi, O 3 is able to inhibit the fungi’s growth, interacting in the same way as bacteria [ 183 , 184 ]. In viruses, O 3 damages the viral capsid and breaks the reproductive cycle by disrupting the contact between the virus and the cell through the process of peroxidation.…”