Mathematical description of combined action of ultrasound and hyperthermia on yeast cells

Some general regularities of synergistic interaction of hyperthermia with various physical and chemical inactivating agents

“…Diploid Saccharomyces cerevisiae yeast cells (strain XS800) were also subjected to the simultaneous action of 20 kHz ultrasound and hyperthermia. Some results have already been published 9 . New results on the relationship between synergism, exposure temperature and ultrasound intensity are presented in ®gure 5.…”

Comparative real-time analysis of Saccharomyces cerevisiae cell viability, injury and death induced by ultrasound (20kHz) and heat for the application of hurdle technology

“…Synergy between ultrasonication and heat to inactivate S. cerevisiae has been documented, but the actual mechanisms are unknown (Ciccolini et al, 1997;United States Food and Drug Administration, Centre for Food safety and Applied Nutrition, 1-6, 2000;Komarova & Zhurakovskaia, 2000;Lorincz, 2004;Petin et al, 1999). In this study, S. cerevisiae was treated with 1 min ultrasound and then added to sterile physiological saline pre-heated either to 55 or 60°C, and then analysed using TO and PI.…”

“…In 1975, using light microscopy, Alliger (1975, showed that the disruption of subcellular particles in sonicated S. cerevisiae occurred rapidly, prior to breakage of cell walls. Using methylene blue as an indicator of S. cerevisiae metabolic status, others showed that intracellular cavitation caused early cell perturbation (Ciccolini et al, 1997;Lorincz, 2004;Petin et al, 1999). Early modification of cell contents prior to cell wall damage was indicated when calorimetry was used to observe changes in yeast cell metabolism (Tsukamoto et al, 2004a).…”

“…It is known that ultrasonic cavitation and heat act synergistically to inactivate S. cerevisiae. When applied together to contaminated liquids, these "hurdles" enhance microbial death (Ciccolini, Taillandier, Wilhelm, Delmas, & Strehaiano, 1997;Guerrero, Lopez-Malo, & Alzamoro, 2001;Komarova & Zhurakovskaia 2000;Lorincz, 2004;Petin, Zhurakovskaya, & Komarova, 1999). In the latter studies, classical serial dilution and colony forming unit (c.f.u.)…”

Ultrasonication for tomato pectinmethylesterase inactivation: effect of cavitation intensity and temperature on inactivation

“…This approach of analyzing a combined treatment has been used by Petin, Zhurakovskaya, and Komarova (1999) to identify the synergistic effect for the simultaneous action of ultrasound and hyperthermia on yeast cells. Although the synergistic effect of combining heat with power ultrasound (thermosonication) has been well documented by Ordóñ ez et al, 1984, Ordó ñ ez, Aguilera, García, andSanz (1987), and Wrigley and Llorca (1992) in microbial inactivation tests, few have studied the effect of the combination of heat with ultrasound on enzyme inactivation.…”