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Effect of UVC-LED and ultrasound alone and combined on heat-resistant Escherichia coli isolated from pasteurised milk |
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| Authors: | Maxsueli Aparecida Moura Machado Vinicius Silva Castro Maria Lúcia Guerra Monteiro Yago Alves de Aguiar Bernardo Eduardo Eustáquio de Souza Figueiredo Carlos Adam Conte-Junior |
| Affiliation: | 1. Postgraduate Program in Food Science (PPGCAL), Chemistry Institute, Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro, 21941-909 RJ, Brazil;2. University of Lethbridge, 4401 University Drive Lethbridge, Lethbridge, Alberta, T1K 3M4 Canada;3. Center for Food Analysis (NAL), Technological Development Support Laboratory (LADETEC), Federal University of Rio de Janeiro (UFRJ), Cidade Universitaria, Rio de Janeiro, 21941-598 RJ, Brazil;4. Postgraduate program in Animal Science (PPGCA), Federal University of Mato Grosso (UFMT), Cuiabá, Mato Grosso, 78060-900 Brazil |
| Abstract: | We aimed at characterising the nonthermal technologies resistance profile of two Escherichia coli strains isolated from pasteurised milk and described as moderate-to-high heat resistance (MHR) (60°C/6 min) harbouring or not a transmissible locus of stress tolerance (tLST). The characterisation was carried out applying optimised conditions of ultraviolet-C light-emitting diodes (UVC-LED) (4950 mJ/cm2), ultrasound (US) (299 W) and their combination (UVC-LED + US). Both strains were more sensitive to UVC-LED (4.5–1.5 log cfu/mL) than to US (<1 log cfu/mL) or UVC-LED + US (4.5–1.5 log cfu/mL), which did not exhibit synergism. Thus, UVC-LED is a promising technology to eliminate E. coli harbouring tLST. |
| Keywords: | Ultraviolet-C light-emitting diodes Sonication Transmissible locus of stress tolerance Dairy products Heat treatment Central composite rotatable design |