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

Costello, Katie, Gutierrez-Merino, Jorge, Bussemaker, Madeleine, Ramaiolia, M, Baka, M, Van Impe, J and Velliou, Eirini (2018) Modelling the microbial dynamics and antimicrobial resistance development of Listeria in viscoelastic food model systems of various structural complexities International Journal of Food Microbiology, 286. pp. 15-30.

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Abstract

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 10oC, 30oC and 37oC 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 (10oC). 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.

Item Type: Article
Divisions : Faculty of Engineering and Physical Sciences > Chemical and Process Engineering
Authors :
NameEmailORCID
Costello, Katiek.costello@surrey.ac.uk
Gutierrez-Merino, Jorgej.gutierrez@surrey.ac.uk
Bussemaker, Madeleinem.bussemaker@surrey.ac.uk
Ramaiolia, M
Baka, M
Van Impe, J
Velliou, Eirinie.velliou@surrey.ac.uk
Date : 11 July 2018
DOI : 10.1016/j.ijfoodmicro.2018.07.011
Copyright Disclaimer : © 2018. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/
Uncontrolled Keywords : Listeria Stress adaptation Nisin Xanthan gum Whey protein Surface/immersed growth
Depositing User : Melanie Hughes
Date Deposited : 12 Jul 2018 09:50
Last Modified : 02 Sep 2019 11:34
URI: http://epubs.surrey.ac.uk/id/eprint/848701

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