Pasteurization of Apple Juice Contaminated with Escherichia coli by a Combined UV-Mild Temperature Treatment

Gayán, Elisa (Universidad de Zaragoza) ; Serrano, María J. (Universidad de Zaragoza) ; Monfort, Silbia ; Álvarez, Ignacio (Universidad de Zaragoza) ; Condón, Santiago (Universidad de Zaragoza)

Resumen: The bactericidal efficacy of ultraviolet (UV) treatments to fruit juices is limited because of their low UV transmittance; therefore, it is necessary to design combined processes to improve their lethality. This investigation
was carried out to determinate the lethal effect of UV-C treatments at mild temperatures (UV-H treatments) on the UV-resistant Escherichia coli strain Spanish Type Culture Collection (STCC) 4201 suspended in apple juice. A synergistic effect was observed and the optimum temperature for the combined process was established. Subsequently,
the effect of the optimized treatment on the lethality of an E. coli cocktail (STCC 4201, STCC 471, American Type Culture Collection (ATCC) 27325, ATCC 25922, and O157:H7 Chapman strain) and on freshly squeezed apple juice quality was evaluated. A UV treatment of 20.33 J/mL reached 0.61±0.01, 0.83±0.07, 1.38 ±0.04, 1.97±0.06, 3.72±0.14,5.67±0.61, and more than 6 log10 cycles of inactivation at 25.0, 40.0, 50.0, 52.5, 55.0, 57.5, and 60.0 °C, respectively. The optimum conditions for exploiting the synergistic effects were UV doses of 27.10 J/mL, temperature of 55.0 °C, and 3.58 min of treatment time. This treatment guaranteed more of 5 log10 reductions of the cocktail of five strains of E. coli without affecting pH, °Brix, and acidity of freshly squeezed apple juice. The UV-H treatment did not increase the loss of ascorbic acid compared to the same UV treatment at room temperature but approximately
doubled the inactivation of polifenoloxidase.

Idioma: Inglés

DOI: 10.1007/s11947-012-0937-z

Año: 2013

Publicado en: Food and Bioprocess Technology 6, 11 (2013), 3006-3016
ISSN: 1935-5130

Factor impacto JCR: 3.126 (2013)

Categ. JCR: FOOD SCIENCE & TECHNOLOGY rank: 12 / 121 = 0.099 (2013) - Q1 - T1

Financiación: info:eu-repo/grantAgreement/ES/CICYT-FEDER/CIT-020000-2009-40

Tipo y forma: Article (PostPrint)

Área (Departamento): Área Tecnología de Alimentos (Dpto. Produc.Animal Cienc.Ali.)