Inactivation of Bacillus spores by gaseous ozone

Abstract

The sporicidal activity of ozone in the gas phase was investigated. Spores of six strains of Bacillus species deposited on filter paper or glass fibre filter were conditioned at different relative humidities (r.h.), and then exposed to ozone ranging in concentration from 0.5 to 3.0 mg/l at different r.h. There was a lag phase in the initial stage of exposure followed by an exponential decrease in the number of survivors with time, although no lag phase was observed with one strain. Inactivation rates increased with increasing exposure r.h. while no significant inactivation was attained at a r.h. of 50% or below. The conditioning r.h. influenced the duration of the lag phase. The D-values (decimal reduction time) in the logarithmic phase varied roughly in inverse proportion to the ozone concentration.

Changes in physicochemical characteristics of ozone-treated raw white rice

“…Ozone has been reported to have hostile effects towards insects, fungi and its anti-microbial characteristics have been proven to effectively kill 90 % of microbial populations (Ishizaki et al 1986;Shah et al 2011). Moreover, ozone has been deemed as a safe fumigation alternative and a good antimicrobial agent and it is preferred in food handling and hygiene industry.…”

Destruction de Rhizopus stolonifer et Botrytis cinerea par des traitements ozone/ions

“…Elford et Van den Ende (1942) ont démontré que l'ozone, à une concentration aussi faible que 5 x 10 -2 ppb possède une action germicide sur certains microorganismes pathogènes à une humidité relative comprise entre 60 et 80 %. Le puissant pouvoir oxydant de l'ozone en a fait un agent utile pour l'inactivation des bactéries, des moisissures et de leurs spores, des virus et des kystes de protozoaires (Broadwater et al 1973;Foegeding 1985;Greene et al 1993;Ishizaki et al 1986;White 1992). Cependant, peu d'intérêt a été accordé à l'utilisation de l'ozone sous forme gazeuse comme désinfectant (Russel 1982).…”

“…L'ozone réagit sur divers acides aminés des protéines, les acides aminés portant des groupements thiols (méthionine et cystéine) et le tryptophane étant les plus sensibles (Menzel 1971;Mudd et al 1969). La présence d'une certaine quantité d'humidité relative semble être essentielle pour une pénétration rapide de l'ozone (Hoigné et Bader 1976;Ishizaki et al 1986). …”

Effect of Ozone on the Surface Charge and Cleanability of Stainless Steel.

“…Ozone is a strong oxidant and it leaves no residual toxic effects after decomposition to oxygen. Ozone has been demonstrated to be useful for microbial sterilization (Ishizaki et al 1986;Restaino et al, 1995;Zhao and Cranston, 1995), postharvest storage of fruits (Barth et al, 1995), regeneration of ceramic membranes (Moulin et al, 1991), and improvement of cleaning efficiency (Takehara et al, 2000;Urano and Fukuzaki, 2001). On the other hand, ozone can damage not only biological materials but also equipment materials, e.g., plastics, elastomers, and metals, resulting in qualitative changes (Murray, 1994).…”