Journal ArticleDOI
Inactivation of Escherichia coli, Listeria innocua and Saccharomyces cerevisiae by UV-C light: Study of cell injury by flow cytometry
Marcela Liliana Schenk,Silvia Raffellini,Sandra N. Guerrero,Guillermo A. Blanco,Stella M. Alzamora +4 more
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TLDR
The results showed that mechanisms of cellular damage differed according to time of exposure to ultraviolet radiation and the organism tested, and FCM was used to detect the inactivation of those L. innocua sub-populations of viable microorganisms which were non-culturable due to membrane rupture and thus not detectable by viable plate count technique.Abstract:
Flow cytometry (FCM) is a powerful tool for analyzing physiological characteristics of microorganisms on a single-cell basis and identifying heterogeneities within population This work analyzed the UV-C induced damage on Escherichia coli ATCC 11229; Listeria innocua ATCC 33090 and Saccharomyces cerevisiae KE162 cells by applying flow cytometry technique The UV-C doses, obtained by altering the exposure time and measured by the iodide-iodate chemical actinometer, ranged between 0 and 5 kJ/m2 E coli; L innocua and S cerevisiae populations were quantified by plate count technique For flow cytometry studies, cells were labeled with fluorescein diacetate (FDA) for detecting membrane integrity and esterase activity, and with propidium iodide (PI) for monitoring membrane integrity The results showed that mechanisms of cellular damage differed according to time of exposure to ultraviolet radiation and the organism tested E coli and S cerevisiae sub-populations with PI increased within the first minutes of UV-C treatment, without much change afterwards On the contrary, FCM was used to detect the inactivation of those L innocua sub-populations of viable microorganisms (maintaining metabolic activity) which were non-culturable due to membrane rupture and thus not detectable by viable plate count techniqueread more
Citations
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Wavelength dependence of biological damage induced by UV radiation on bacteria
Ana L. Santos,Vanessa Oliveira,Inês Baptista,Isabel Henriques,Newton C. M. Gomes,Adelaide Almeida,António Correia,Ângela Cunha +7 more
TL;DR: Analysis of biological effects of UV radiation of different wavelengths revealed that survival under UVA, UVB and UVC wavelengths was best explained by DSB, oxidative damage to lipids, and intracellular ROS levels, respectively.
Journal ArticleDOI
Disinfection of selected vegetables under nonthermal treatments: Chlorine, acid citric, ultraviolet light and ozone
TL;DR: In this paper, four disinfection methods were compared for effectiveness with citric acid (0.5, 1 and 1.5%), ultraviolet light (UV-C), and ozone (5ppm) to inactivate Escherichia coli ATCC 11775.
Journal ArticleDOI
Evaluation of Ultrasound-Induced Damage to Escherichia coli and Staphylococcus aureus by Flow Cytometry and Transmission Electron Microscopy.
TL;DR: Investigating ultrasound-induced damage to Escherichia coli and Staphylococcus aureus revealed that cells ruptured and disintegrated by ultrasound cannot be revived, which can be considered an advantage of ultrasound over other nonthermal techniques.
Journal ArticleDOI
Removal of Microcystis aeruginosa by potassium ferrate (VI): Impacts on cells integrity, intracellular organic matter release and disinfection by-products formation
TL;DR: It is demonstrated potassium ferrate (VI) could act as a dual-functional chemical reagent (i.e., oxidant and coagulant) and may be potentially used in addressing the algal-rich drinking water.
Journal ArticleDOI
Hurdle Technology in Fruit Processing
TL;DR: This review examines innovative hurdle techniques to obtain novel fruit products with fresh-like characteristics based on emerging preservation factors in combination or combining emerging factors with traditional ones.
References
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Existing and potential applications of ultraviolet light in the food industry - a critical review
TL;DR: The penetration of UVA into water is better than that of UVC, and its bacteriocidal action in the presence of photosensitisers can be rapid, however, pure furocoumarins are expensive and their addition to foodstuffs might be questioned on safety grounds.
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Encyclopedia of food microbiology
TL;DR: The present study focuses on the development of methods for isolating and quantifying the phytochemical properties of E.coli of the Enterobacteriaceae, Coliforms and E. Coli found in Milk and Milk Products.
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Advantages and Limitations on Processing Foods by UV Light
TL;DR: In this article, the authors proposed a method to reduce microbial load through UV light application as a disinfection medium for food products other than liquids, instead of thermal treatment or application of antimicrobial compounds.
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Analysis of bacterial function by multi-colour fluorescence flow cytometry and single cell sorting.
TL;DR: Analysis of bacterial fermentations showed a considerable drop in membrane potential and integrity during the latter stages of small scale (5L), well mixed fed-batch fermentations, suggesting 'on-line' flow cytometry could improve process control.
Journal ArticleDOI
Advances in Ultraviolet Light Technology for Non-thermal Processing of Liquid Foods
TL;DR: A summary of the basic principles of UV light generation and propagation with emphasis on its applications for liquid food processing can be found in this paper, which includes information on critical product and process factors that affect UV light inactivation and consequently the delivery of a required scheduled process in liquids foods.