Heat inactivation of Escherichia coli K12 MG1655: Effect of microbial metabolites and acids in spent medium

Velliou, Eirini; Derlinden, Eva Van; Cappuyns, Astrid; Devlieghere, Frank; Impe, Jan Van

doi:10.1016/j.jtherbio.2011.11.001

Cited by 13 publications

(11 citation statements)

References 27 publications

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“…Cells grown as colonies on the surface of a solid or solid(like) system experience a significantly different biochemical and structural environment in comparison to planktonic growth in liquid systems. Diffusional limitations of oxygen and nutrients will exist at colony level, and (acidic) metabolic products will accumulate around the colony, causing a self‐induced (acid) stress that may affect the microbial kinetics and microbial environmental response . Additionally, in co‐culture systems the spatial organization, colony size, and location of each species can affect their inter‐and intra‐species interaction and communication, which will directly affect the environmental stress within a colony, affecting the growth kinetics of both the pathogen and the naturally present bacteria .…”

Section: Introductionmentioning

confidence: 99%

“…Additionally, in co‐culture systems the spatial organization, colony size, and location of each species can affect their inter‐and intra‐species interaction and communication, which will directly affect the environmental stress within a colony, affecting the growth kinetics of both the pathogen and the naturally present bacteria . Overall, microorganisms could display a different level of AMR development due to environmental stress adaptation and cross protection …”

Section: Introductionmentioning

confidence: 99%

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A multi‐scale analysis of the effect of complex viscoelastic models on Listeria dynamics and adaptation in co‐culture systems

et al. 2019

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Natural antimicrobials are of interest to replace traditional food decontamination methods: they are milder and maintain desirable sensory characteristics. However, efficacy can be affected by food structure/composition, thus structural effects in a co-culture pathogen/microflora system are investigated. Listeria was grown planktonically (liquid broth) or on a biphasic viscoelastic system, in monoculture with/without artificial nisin, or in co-culture with Lactococcus lactis (nisin/non-nisin producing). Microbial growth kinetics were monitored and advanced microscopy techniques were utilized to quantify cellular interactions and spatial organization. Microstructural effects are observed on the kinetics, with differences in monoculture/co-culture. Significant microscopic differences are observed in spatial organization and colony size. We are the first to observe changing growth location for all species in monoculture/co-culture, with differences in colony size/organization through stationary phase. This study provides insight into the environmental stress response/adaptation of Listeria grown on structured systems in response to L. lactis and natural antimicrobials.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A multi‐scale analysis of the effect of complex viscoelastic models on Listeria dynamics and adaptation in co‐culture systems

et al. 2019

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“…More specifically, in a solid system, microorganisms evolve as colonies and due to diffusional limitations of oxygen and nutrients, as well as the accumulation of (acidic) metabolic products around the colony, micro-organisms may experience a self-induced (acid) stress that could affect their overall kinetics and response to various environmental factors. Additionally, microorganisms grown as colonies could display/develop a different level of antimicrobial resistance due to environmental stress adaptation and cross protection (Aspridou et al, 2014;Baka et al, 2013;Noriega et al, 2013;Velliou et al, 2010Velliou et al, , 2011Velliou et al, , 2012Velliou et al, , 2013Yousef and Juneja, 2003). For example, significant differences in microbial kinetics have been reported in food model systems as compared to liquid broths for both growth (Antwi et al, 2008;Brocklehurst et al, 1997;Noriega et al, 2010a;Skandamis and Jeanson, 2015;Theys et al, 2009;Wilson et al, 2002) and inactivation studies (Baka et al, 2017b;Velliou et al, 2013;Wang et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

Modelling the microbial dynamics and antimicrobial resistance development of Listeria in viscoelastic food model systems of various structural complexities

Costello

Gutierrez-Merino

Bussemaker

et al. 2018

International Journal of Food Microbiology

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Minimal processing for microbial decontamination, such as the use of natural antimicrobials, is gaining interest in the food industry as these methods are generally milder than conventional processing, therefore better maintaining the nutritional content and sensory characteristics of food products. The aim of this study was to quantify the impact of (i) structural composition and complexity, (ii) growth location and morphology, and (iii) the natural antimicrobial nisin, on the microbial dynamics of Listeria innocua. More specifically, viscoelastic food model systems of various compositions and internal structure were developed and characterised, i.e. monophasic Xanthan gum-based and biphasic Xanthan gum/Whey protein-based viscoelastic systems. The microbial dynamics of L. innocua at 10 °C, 30 °C and 37 °C were monitored and compared for planktonic growth in liquid, or in/on (immersed or surface colony growth) the developed viscoelastic systems, with or without a sublethal concentration of nisin. Microscopy imaging was used to determine the bacterial colony size and spatial organisation in/on the viscoelastic systems. Selective growth of L. innocua on the protein phase of the developed biphasic system was observed for the first time. Additionally, significant differences were observed in the colony size and distribution in the monophasic Xanthan gum-based systems depending on (i) the type of growth (surface/immersed) and (ii) the Xanthan gum concentration. Furthermore, the system viscosity in monophasic Xanthan gum-based systems had a protective role against the effects of nisin for immersed growth, and a further inhibitory effect for surface growth at a suboptimal temperature (10 °C). These findings give a systematic quantitative insight on the impact of nisin as an environmental challenge on the growth and spatial organisation of L. innocua, in viscoelastic food model systems of various structural compositions/complexities. This study highlights the importance of accounting for system structural composition/complexity when designing minimal food processing methods with natural antimicrobials.

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“…The rationale for the selection of these microorganisms was to use different groups of bacteria with different cell wall structures and heat resistance to investigate the effectiveness of the photothermal inactivation method using NPGD random arrays. In this study, E. coli MG 1655 was selected because it is a surrogate for other pathogenic E. coli strains that can be inactivated at temperatures <60 °C [25]. B. subtilis is able to survive temperatures over 50 °C and Exiguobacterium sp.…”

Section: Introductionmentioning

confidence: 99%

Photothermal inactivation of heat-resistant bacteria on nanoporous gold disk arrays

Santos¹,

Ferrara²,

Zhao³

et al. 2016

Opt. Mater. Express

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A rapid photothermal bacterial inactivation technique has been developed by irradiating near-infrared (NIR) light onto bacterial cells (Escherichia coli, Bacillus subtilis, Exiguobacterium sp. AT1B) deposited on surfaces coated with a dense, random array of nanoporous gold disks (NPGDs). With the use of cell viability tests and SEM imaging results, the complete inactivation of the pathogenic and heat-resistant bacterial model strains is confirmed within ~25 s of irradiation of the NPGD substrate. In addition to irradiation control experiments to prove the efficacy of the bacterial inactivation, thermographic imaging showed an immediate averaged temperature rise above 200 °C within the irradiation spot of the NPGD substrate. The light-gated photothermal effects on the NPGD substrate offers potential applications for antimicrobial and nanotherapeutic devices due to strong light absorption in the tissue optical window, i.e., the NIR wavelengths, and robust morphological structure that can withstand high instantaneous thermal shocks.

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Heat inactivation of Escherichia coli K12 MG1655: Effect of microbial metabolites and acids in spent medium

Cited by 13 publications

References 27 publications

A multi‐scale analysis of the effect of complex viscoelastic models on Listeria dynamics and adaptation in co‐culture systems

A multi‐scale analysis of the effect of complex viscoelastic models on Listeria dynamics and adaptation in co‐culture systems

Modelling the microbial dynamics and antimicrobial resistance development of Listeria in viscoelastic food model systems of various structural complexities

Photothermal inactivation of heat-resistant bacteria on nanoporous gold disk arrays

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