Experimental and computational analysis of microbial inactivation in a solid by ohmic heating using pulsed electric fields

Ariza-Gracia, M.Á. ; Cabello, M.P. ; Cebrián, G. (Universidad de Zaragoza) ; Calvo, B. (Universidad de Zaragoza) ; Álvarez, I. (Universidad de Zaragoza)

Resumen: Pulsed electric field technology (PEF) has traditionally been used as a technique to inactivate microorganisms in liquid foods at temperatures below those used in heat treatments; however, application of high-intensity PEF (E>1 kV/cm) at high frequencies (>10 Hz) can allow rapid and volumetric solid food electrical heating in order to replace traditional convection/conduction heating that progresses from the heating medium to the inside of the product. This investigation is the first one to evaluate the inactivation of Salmonella Typhimurium 878 in a solid product (cylinder of technical agar used as reference solid) by applying PEF treatments (2.5 and 3.75 kV/cm, and up to 9000 microseconds) at 50 Hz. The evolution of temperature in different locations of the agar cylinder was measured by observing the variability of heating rates depending on location and PEF intensity. Microbial inactivation was determined and compared with isothermal heat treatments that predicted similar inactivation values, but did not detect additional inactivation. Computational analysis enabled us to predict temperature and microbial inactivation for any spatial and temporal distribution of the cylinder agar by detecting the coldest point in the transition zone between the high-voltage electrode, the agar, and the plastic container of the treatment chamber. In order to evaluate the variability of the temperature, computational predictions were done each 0.5-mm. The difference between the coldest and the hottest point (e.g. at the center of the cylinder) resulted in around 10 °C and 10 second variation in temperature and processing time, respectively. In any case, it was possible to obtain 5-log10-reductions after 60 s of PEF treatments when using 2.5 kV/cm and 50% reduction for 3.75 kV/cm. These results suggested the potential of PEF technology as a rapid heating system based on ohmic heating for microbial inactivation in solid food products.

Idioma: Inglés

DOI: 10.1016/j.ifset.2020.102440

Año: 2020

Publicado en: INNOVATIVE FOOD SCIENCE & EMERGING TECHNOLOGIES 65 (2020), 102440 [9 pp.]
ISSN: 1466-8564

Factor impacto JCR: 5.916 (2020)

Categ. JCR: FOOD SCIENCE & TECHNOLOGY rank: 15 / 144 = 0.104 (2020) - Q1 - T1

Factor impacto SCIMAGO: 1.366 - Chemistry (miscellaneous) (Q1) - Industrial and Manufacturing Engineering (Q1) - Food Science (Q1)

Financiación: info:eu-repo/grantAgreement/ES/DGA/A03-17R
Financiación: info:eu-repo/grantAgreement/ES/DGA/T24-17R
Financiación: info:eu-repo/grantAgreement/ES/MINECO/AGL2017-84084-R
Financiación: info:eu-repo/grantAgreement/ES/MINECO/Consolider-Ingenio2010
Financiación: info:eu-repo/grantAgreement/ES/MINECO/DPI2017-84047-R

Tipo y forma: Article (PostPrint)

Área (Departamento): Área Mec.Med.Cont. y Teor.Est. (Dpto. Ingeniería Mecánica)
Área (Departamento): Área Tecnología de Alimentos (Dpto. Produc.Animal Cienc.Ali.)