130908 20240201151019.0 doi 10.1016/j.ifset.2011.07.008 sideral 74637 ART-2011-74637 eng Gayán,E. Universidad de Zaragoza (orcid)0000-0002-5895-2157 UV-C inactivation of Escherichia coli at different temperatures 2011 The influence of treatment parameters (dose and temperature), treatment medium characteristics (absorption coefficient, pH and water activity) and microbiological factors (strain, growth phase and UV damage and repair capacity) on Escherichia coli UV-C resistance has been investigated. UV-C doses to inactivate at 25 °C 99.99% of the initial population (4D) of five strains of E. coli in McIlvaine buffer of pH 7.0 with tartrazine added (absorption coefficient of 10.77 cm−1) were 16.60, 14.36, 14.36, 13.22, 11.18 J/mL for strains E. coli STCC 4201, STCC 471, STCC 27325, O157:H7 and ATCC 25922, respectively. The entrance in the stationary growth phase increased the 4D value of the most resistant strain, E. coli STCC 4201, from 13.09 to 17.23 J/mL. Survivors to UV treatments showed neither oxidative damages nor injuries in cell envelopes. On the contrary, the photoreactivation by the incubation of plates for 60 min below visible light (11.15 klx) increased the dose to 18.97 J/mL. The pH and the water activity of the treatment medium did not affect the UV tolerance of E. coli STCC 4201, but the lethal effect of the treatments decreased exponentially (Log10 4D = − 0.0628α + 0.624) by increasing the absorption coefficient (α). A treatment of 16.94 J/mL reached 6.35, 4.35, 2.64, 1.93, 1.63, 1.20, 1.02 and 0.74 Log10 cycles of inactivation with absorption coefficients of 8.56, 10.77, 12.88, 14.80, 17.12, 18.51, 20.81 and 22.28 cm−1. The temperature barely changed the UV resistance up to 50.0 °C. Above this threshold, inactivation rates due to the combined process synergistically increased with the temperature. The magnitude of the synergism decreased over 57.5 °C. An UV treatment of 16.94 J/mL in media with an absorption coefficient of 22.28 cm−1 reached 1.23, 1.64, 2.36, 4.01 and 6.22 Log10 cycles of inactivation of E. coli STCC 4201 at 50.0, 52.5, 55.5, 57.5 and 60.0 °C, respectively. info:eu-repo/grantAgreement/ES/CICYT-FEDER/CIT-020000-2009-40 info:eu-repo/semantics/closedAccess All rights reserved http://www.europeana.eu/rights/rr-f/ 3.03 2011 FOOD SCIENCE & TECHNOLOGY 12 / 127 = 0.094 2011 Q1 T1 info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion Monfort,S. Universidad de Zaragoza Álvarez,I. Universidad de Zaragoza (orcid)0000-0003-2430-858X Condón,S. Universidad de Zaragoza (orcid)0000-0002-1902-0648 2008 780 Universidad de Zaragoza Dpto. Produc.Animal Cienc.Ali. Área Tecnología de Alimentos 12, 4 (2011), 531-541 Innov. food sci. emerg. technol. INNOVATIVE FOOD SCIENCE & EMERGING TECHNOLOGIES 1466-8564 838550 http://zaguan.unizar.es/record/130908/files/texto_completo.pdf Versión publicada 2901114 http://zaguan.unizar.es/record/130908/files/texto_completo.jpg?subformat=icon icon Versión publicada oai:zaguan.unizar.es:130908 articulos driver 2024-02-01-14:40:40 ARTICLE