Inactivation kinetics of Escherichia coli O157:H7 and Salmonella Typhimurium on organic carrot (Daucus carota L.) treated with low concentration electrolyzed water combined with short-time heat treatment. (December 2019)

• Record Type: Journal Article
• Authors: Liu, Qin; Jin, Xiaoxuan; Feng, Xiao; Yang, Hongshun; Fu, Caili
• Is Part Of: Food control. Volume 106(2019)
• Publication Date: 2019-12
• Subjects: Electrolyzed water -- Electrolyzed oxidizing water -- Electrolysed water -- Weibull model -- Organic vegetable -- Atomic force microscopy -- Escherichia coli O157:H7 -- Salmonella Typhimurium -- Organic food -- Food nanotechnology -- Minimal processing -- Pathogen -- Heat treatment -- Carrot -- Postharvest -- Fresh-cut -- Fresh produce -- Modelling -- Prediction -- Sanitation; Food -- Quality -- Periodicals; Food -- Analysis -- Periodicals; Food handling -- Periodicals; Food industry and trade -- Quality control -- Periodicals; Aliments -- Industrie et commerce -- Qualité -- Contrôle -- Périodiques; Aliments -- Qualité -- Périodiques; Aliments -- Analyse -- Périodiques; Hygiène alimentaire -- Périodiques; Food -- Analysis; Food handling; Food -- Quality; Periodicals; Electronic journals; 664.07
• DOI: 10.1016/j.foodcont.2019.06.028
• Languages: English
• ISSNs: 0956-7135

Abstract

Abstract: In the present study, the synergistic disinfection efficacy of low concentration electrolyzed water (LcEW) (free available chlorine, 4 mg/L) combined with brief heat enhancement was evaluated and the bactericidal mechanism was investigated by atomic force microscopy (AFM). The inactivation kinetics of Escherichia coli O157:H7 and Salmonella Typhimurium on organic carrot were fitted with Weibull model to evaluate the synergistic effects. LcEW is effective at inactivating E. coli O157:H7 and S . Typhimurium on organic carrots, and the efficacy is dependent on the temperature. The combined treatment with LcEW at 80 °C resulted in decimal reduction time ( T R ) of 7.42 and 3.27 s for E. coli O157:H7 and S. Typhimurium, respectively. The reactive oxygen species generated from LcEW were responsible for the microbial inactivation. In addition, AFM observation of E. coli O157:H7 and S. Typhimurium revealed morphological alterations in the bacterial cell structure, which illustrated the damage of cell membrane injury and intracellular component leakage. Quality attributes of carrot treated with LcEW and short-time heating (70 °C, 1 min) were not significantly different from controls. Compared to the control group, the combined treatment exhibited significantly ( P < 0.05) greater inhibition of naturally occurring microbiota on organic carrots during storage at 4 °C. Consequently, the application of LcEW combined with short-time heat improved safety of organic carrot, without negatively affecting the sensory properties, which can be explored by the organic industry. Highlights: Electrolyzed water inactivated E. coli O157:H7 and Salmonella in organic carrot. Weibull model satisfactorily described the nonlinear survival kinetics of the pathogens. Rising temperatures and electrolyzed water dramatically reduced the T R value. Natural microflora on organic carrot were inactivated as well. AFM images of EW treated bacteria cells revealed severe damage.