title: Zygosaccharomyces bailii inactivation by means of UV light and low-frequency ultrasound treatments.
abstract: Zygosaccharomyces bailii inactivation suspended in apple juice was evaluated under the effects of selected treatments: short-wave UV light (UVC, using one or two lamps), or low-frequency ultrasound (US), or their simultaneous combination. US treatments (20 kHz, 120-μm wave  amplitude) were performed at 35°C in a double-wall vessel by using a 13-mm probe. The UVC device consists of two 90-cm-long stainless steel tubes with 40-W UVC lamps covered with quartz tubes, each one inside a stainless steel tube (annular inside diameter of 2.6 cm) connected to a peristaltic  pump. Inoculated systems were recirculated through individual or simultaneous US and UVC treatments, samples were taken periodically, and yeast survivors were determined by the plate-count technique. Yeast survival curves demonstrated that UVC alone or in combination with US produced higher  inactivation than US alone. Survival curves were appropriately described by the Weibull distribution of resistances model, obtaining model parameter values that adequately reflected the effect of the studied treatments. For every tested case, the distribution of resistances model revealed  an absence of mode, while mean values and variances decreased when simultaneous UVC irradiation with two lamps and US were applied, reaching a 7-log cycle reduction after 40 min of treatment. Combined treatment was more effective than individual US or UVC treatments.
authors: Departamento de Ingeniería Química, Alimentos y Ambiental, Universidad de las Américas Puebla, Cholula, Puebla, 72820 Mexico.
authors: J J
authors: JJ
authors: Gómez-Díaz
authors: A
authors: A
authors: Santiesteban-López
authors: E
authors: E
authors: Palou
authors: A
authors: A
authors: López-Malo
mesh_terms: D001628:Beverages / Q000382:microbiology*; D015169:Colony Count, Microbial; D003257:Consumer Product Safety; D005506:Food Contamination / Q000517:prevention & control; D005511:Food Handling / Q000379:methods; D005514:Food Irradiation; D005516:Food Microbiology; D006801:Humans; D007700:Kinetics; D027845:Malus / Q000382:microbiology*; D050296:Microbial Viability; D014465:Ultrasonics / Q000379:methods*; D014466:Ultraviolet Rays; D020068:Zygosaccharomyces / Q000254:growth & development* / Q000528:radiation effects