1
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Studying the effect of oxygen availability and matrix structure on population density and inter-strain interactions of Listeria monocytogenes in different dairy model systems. Food Res Int 2022; 156:111118. [DOI: 10.1016/j.foodres.2022.111118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Revised: 03/05/2022] [Accepted: 03/08/2022] [Indexed: 11/20/2022]
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2
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Verheyen D, Van Impe JFM. The Inclusion of the Food Microstructural Influence in Predictive Microbiology: State-of-the-Art. Foods 2021; 10:foods10092119. [PMID: 34574229 PMCID: PMC8468028 DOI: 10.3390/foods10092119] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 08/27/2021] [Accepted: 08/30/2021] [Indexed: 12/15/2022] Open
Abstract
Predictive microbiology has steadily evolved into one of the most important tools to assess and control the microbiological safety of food products. Predictive models were traditionally developed based on experiments in liquid laboratory media, meaning that food microstructural effects were not represented in these models. Since food microstructure is known to exert a significant effect on microbial growth and inactivation dynamics, the applicability of predictive models is limited if food microstructure is not taken into account. Over the last 10-20 years, researchers, therefore, developed a variety of models that do include certain food microstructural influences. This review provides an overview of the most notable microstructure-including models which were developed over the years, both for microbial growth and inactivation.
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Affiliation(s)
- Davy Verheyen
- BioTeC+, Chemical and Biochemical Process Technology and Control, Department of Chemical Engineering, KU Leuven, Gebroeders de Smetstraat 1, 9000 Ghent, Belgium;
- OPTEC, Optimization in Engineering Center-of-Excellence, KU Leuven, 3000 Leuven, Belgium
- CPMF2, Flemish Cluster Predictive Microbiology in Foods—www.cpmf2.be, 9000 Ghent, Belgium
| | - Jan F. M. Van Impe
- BioTeC+, Chemical and Biochemical Process Technology and Control, Department of Chemical Engineering, KU Leuven, Gebroeders de Smetstraat 1, 9000 Ghent, Belgium;
- OPTEC, Optimization in Engineering Center-of-Excellence, KU Leuven, 3000 Leuven, Belgium
- CPMF2, Flemish Cluster Predictive Microbiology in Foods—www.cpmf2.be, 9000 Ghent, Belgium
- Correspondence:
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3
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Schelegueda LI, Zalazar AL, Herbas ET, Gliemmo MF, Campos CA. Effect of gellan gum, xylitol and natamycin on Zygosaccharomyces bailii growth and rheological characteristics in low sugar content model systems. Int J Biol Macromol 2020; 164:1657-1664. [PMID: 32777415 DOI: 10.1016/j.ijbiomac.2020.07.277] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 07/14/2020] [Accepted: 07/19/2020] [Indexed: 10/23/2022]
Abstract
This study evaluated the effect of some natural additives and the structure imparted by them on microbial growth and rheological characteristics in acidic model foods with reduced glycidic content. Systems were formulated using gellan gum, as gelling agent; xylitol, as aw depressor; and natamycin, as antimicrobial. Additive-free control systems were prepared. The pH was adjusted to 3.50 or 5.50 as required. Systems were inoculated with Zygosaccharomyces bailii. The effect of additives alone and combined on Z. bailii growth was studied. In some cases, the possible use of additives as yeast nutrients was evaluated. Furthermore, systems rheological characterization was performed. Additives and the structure given by gellan gum significantly affected yeast growth. Gellan gum initially slowed Z. bailii development, but as storage progressed, it acted as yeast carbon source, promoting its growth. A similar trend was observed when xylitol effect was studied. Natamycin inhibited yeast growth in all systems assayed. Additives modified the rheological characteristics of the gels and this effect depended on gellan gum concentration and pH. Obtained results emphasize the importance of considering the different effects that additives and their combinations can exert on the growth of deteriorating microorganisms and on the physical characteristics of gels.
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Affiliation(s)
- Laura Inés Schelegueda
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Industrias, Buenos Aires, Argentina; CONICET - Universidad de Buenos Aires, Instituto de Tecnología de Alimentos y Procesos Químicos (ITAPROQ), Buenos Aires, Argentina
| | - Aldana Lourdes Zalazar
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Industrias, Buenos Aires, Argentina; CONICET - Universidad de Buenos Aires, Instituto de Tecnología de Alimentos y Procesos Químicos (ITAPROQ), Buenos Aires, Argentina
| | - Elizeth Tania Herbas
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Industrias, Buenos Aires, Argentina
| | - María Fernanda Gliemmo
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Industrias, Buenos Aires, Argentina; CONICET - Universidad de Buenos Aires, Instituto de Tecnología de Alimentos y Procesos Químicos (ITAPROQ), Buenos Aires, Argentina
| | - Carmen Adriana Campos
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Industrias, Buenos Aires, Argentina; CONICET - Universidad de Buenos Aires, Instituto de Tecnología de Alimentos y Procesos Químicos (ITAPROQ), Buenos Aires, Argentina.
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4
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Zalazar AL, Gliemmo MF, Soria M, Campos CA. Modelling growth/no growth interface of Zygosaccharomyces bailii in simulated acid sauces as a function of natamycin, xanthan gum and sodium chloride concentrations. Food Res Int 2019; 116:916-924. [DOI: 10.1016/j.foodres.2018.09.028] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2018] [Revised: 08/28/2018] [Accepted: 09/08/2018] [Indexed: 10/28/2022]
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5
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Verheyen D, Bolívar A, Pérez-Rodríguez F, Baka M, Skåra T, Van Impe JF. Effect of food microstructure on growth dynamics of Listeria monocytogenes in fish-based model systems. Int J Food Microbiol 2018; 283:7-13. [DOI: 10.1016/j.ijfoodmicro.2018.05.032] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Revised: 04/25/2018] [Accepted: 05/31/2018] [Indexed: 11/26/2022]
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6
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Development of fish-based model systems with various microstructures. Food Res Int 2018; 106:1069-1076. [DOI: 10.1016/j.foodres.2017.12.047] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Revised: 12/15/2017] [Accepted: 12/16/2017] [Indexed: 02/07/2023]
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7
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Lobete MM, Noriega E, Batalha MA, de Beurme S, Van de Voorde I, Van Impe JF. Effect of tagatose on growth dynamics of Salmonella Typhimurium and Listeria monocytogenes in media with different levels of structural complexity and in UHT skimmed milk. Food Control 2017. [DOI: 10.1016/j.foodcont.2016.05.049] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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8
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Baka M, Vercruyssen S, Cornette N, Van Impe JF. Dynamics of Listeria monocytogenes at suboptimal temperatures in/on fish-protein based model systems: Effect of (micro)structure and microbial distribution. Food Control 2017. [DOI: 10.1016/j.foodcont.2016.06.031] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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9
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Maia MRG, Marques S, Cabrita ARJ, Wallace RJ, Thompson G, Fonseca AJM, Oliveira HM. Simple and Versatile Turbidimetric Monitoring of Bacterial Growth in Liquid Cultures Using a Customized 3D Printed Culture Tube Holder and a Miniaturized Spectrophotometer: Application to Facultative and Strictly Anaerobic Bacteria. Front Microbiol 2016; 7:1381. [PMID: 27630632 PMCID: PMC5006086 DOI: 10.3389/fmicb.2016.01381] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Accepted: 08/22/2016] [Indexed: 11/13/2022] Open
Abstract
Here we introduce a novel strategy for turbidimetric monitoring of bacterial growth in liquid culture. The instrumentation comprises a light source, a customized 3D printed culture tube holder and a miniaturized spectrophotometer, connected through optical cables. Due to its small footprint and the possibility to operate with external light, bacterial growth was directly monitored from culture tubes in a simple and versatile fashion. This new portable measurement technique was used to monitor the growth of facultative (Escherichia coli ATCC/25922, and Staphylococcus aureus ATCC/29213) and strictly (Butyrivibrio fibrisolvens JW11, Butyrivibrio proteoclasticus P18, and Propionibacterium acnes DSMZ 1897) anaerobic bacteria. For E. coli and S. aureus, the growth rates calculated from normalized optical density values were compared with those ones obtained using a benchtop spectrophotometer without significant differences (P = 0.256). For the strictly anaerobic species, a high precision (relative standard deviation < 3.5%) was observed between replicates up to 48 h. Regarding its potential for customization, this manifold could accommodate further developments for customized turbidimetric monitoring, such as the use of light-emitting diodes as a light source or flow cells.
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Affiliation(s)
- Margarida R G Maia
- REQUIMTE, LAQV, ICBAS, Instituto de Ciências Biomédicas de Abel Salazar, Universidade do PortoPorto, Portugal; REQUIMTE, LAQV, DGAOT, Faculdade de Ciências, Universidade do PortoPorto, Portugal
| | - Sara Marques
- CIBIO, InBIO-Research Network in Biodiversity and Evolutionary Biology, Universidade do PortoVairão, Portugal; Departamento Clinicas Veterinárias - ICBAS, Instituto de Ciências Biomédicas de Abel Salazar, Universidade do PortoPorto, Portugal
| | - Ana R J Cabrita
- REQUIMTE, LAQV, ICBAS, Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto Porto, Portugal
| | - R John Wallace
- Rowett Institute of Nutrition and Health, University of Aberdeen Aberdeen, UK
| | - Gertrude Thompson
- CIBIO, InBIO-Research Network in Biodiversity and Evolutionary Biology, Universidade do PortoVairão, Portugal; Departamento Clinicas Veterinárias - ICBAS, Instituto de Ciências Biomédicas de Abel Salazar, Universidade do PortoPorto, Portugal
| | - António J M Fonseca
- REQUIMTE, LAQV, ICBAS, Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto Porto, Portugal
| | - Hugo M Oliveira
- REQUIMTE, LAQV, ICBAS, Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto Porto, Portugal
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10
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Baka M, Verheyen D, Cornette N, Vercruyssen S, Van Impe JF. Salmonella Typhimurium and Staphylococcus aureus dynamics in/on variable (micro)structures of fish-based model systems at suboptimal temperatures. Int J Food Microbiol 2016; 240:32-39. [PMID: 27627842 DOI: 10.1016/j.ijfoodmicro.2016.08.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Revised: 07/21/2016] [Accepted: 08/01/2016] [Indexed: 11/30/2022]
Abstract
The limited knowledge concerning the influence of food (micro)structure on microbial dynamics decreases the accuracy of the developed predictive models, as most studies have mainly been based on experimental data obtained in liquid microbiological media or in/on real foods. The use of model systems has a great potential when studying this complex factor. Apart from the variability in (micro)structural properties, model systems vary in compositional aspects, as a consequence of their (micro)structural variation. In this study, different experimental food model systems, with compositional and physicochemical properties similar to fish patés, are developed to study the influence of food (micro)structure on microbial dynamics. The microbiological safety of fish products is of major importance given the numerous cases of salmonellosis and infections attributed to staphylococcus toxins. The model systems understudy represent food (micro)structures of liquids, aqueous gels, emulsions and gelled emulsions. The growth/inactivation dynamics and a modelling approach of combined growth and inactivation of Salmonella Typhimurium and Staphylococcus aureus, related to fish products, are investigated in/on these model systems at temperatures relevant to fish products' common storage (4°C) and to abuse storage temperatures (8 and 12°C). ComBase (http://www.combase.cc/) predictions compared with the maximum specific growth rate (μmax) values estimated by the Baranyi and Roberts model in the current study indicated that the (micro)structure influences the microbial dynamics. Overall, ComBase overestimated microbial growth at the same pH, aw and storage temperature. Finally, the storage temperature had also an influence on how much each model system affected the microbial dynamics.
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Affiliation(s)
- Maria Baka
- CPMF2 - Flemish Cluster Predictive Microbiology in Foods, Belgium(1); BioTeC - Chemical and Biochemical Process Technology and Control, KU Leuven, Belgium.
| | - Davy Verheyen
- CPMF2 - Flemish Cluster Predictive Microbiology in Foods, Belgium(1); BioTeC - Chemical and Biochemical Process Technology and Control, KU Leuven, Belgium
| | - Nicolas Cornette
- CPMF2 - Flemish Cluster Predictive Microbiology in Foods, Belgium(1); BioTeC - Chemical and Biochemical Process Technology and Control, KU Leuven, Belgium
| | - Stijn Vercruyssen
- CPMF2 - Flemish Cluster Predictive Microbiology in Foods, Belgium(1); BioTeC - Chemical and Biochemical Process Technology and Control, KU Leuven, Belgium
| | - Jan F Van Impe
- CPMF2 - Flemish Cluster Predictive Microbiology in Foods, Belgium(1); BioTeC - Chemical and Biochemical Process Technology and Control, KU Leuven, Belgium.
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11
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Baka M, Noriega E, Van Langendonck K, Van Impe JF. Influence of food intrinsic complexity on Listeria monocytogenes growth in/on vacuum-packed model systems at suboptimal temperatures. Int J Food Microbiol 2016; 235:17-27. [PMID: 27393885 DOI: 10.1016/j.ijfoodmicro.2016.06.029] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Revised: 04/26/2016] [Accepted: 06/22/2016] [Indexed: 11/19/2022]
Abstract
Food intrinsic factors e.g., food (micro)structure, compositional and physicochemical aspects, which are mutually dependent, influence microbial growth. While the effect of composition and physicochemical properties on microbial growth has been thoroughly assessed and characterised, the role of food (micro)structure still remains unravelled. Most studies on food (micro)structure focus on comparing planktonic growth in liquid (microbiological) media with colonial growth in/on solid-like systems or on real food surfaces. However, foods are not only liquids or solids; they can also be emulsions or gelled emulsions and have complex compositions. In this study, Listeria monocytogenes growth was studied on the whole spectrum of (micro)structure, in terms of food (model) systems. The model systems varied not only in (micro)structure, which was the target of the study, but also in compositional and physicochemical characteristics, which was an inevitable consequence of the (micro)structural variability. The compositional and physicochemical differences were mainly due to the presence or absence of fat and gelling agents. The targeted (micro)structures were: i) liquids, ii) aqueous gels, iii) emulsions and iv) gelled emulsions. Furthermore, the microbial dynamics were studied and compared in/on all these model systems, as well as on a compositionally predefined canned meat, developed in order to have equal compositional level to the gelled emulsion model system and represent a real food system. Frankfurter sausages were the targeted real foods, selected as a case study, to which the canned meat had similar compositional characteristics. All systems were vacuum packed and incubated at 4, 8 and 12°C. The most appropriate protocol for the preparation of the model systems was developed. The pH, water activity and resistance to penetration of the model systems were characterised. Results indicated that low temperature contributes to growth variations among the model systems. Additionally, the firmer the solid system, the faster L. monocytogenes grew on it. Finally, it was found that L. monocytogenes grows faster on canned meat and real Frankfurters, as found in a previous study, followed by liquids, aqueous gels, emulsions and gelled emulsions. This observation indicates that all model systems, developed in this study, underestimated L. monocytogenes growth. Despite some limitations, model systems are overall advantageous and therefore, their validation is always recommended prior to further use.
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Affiliation(s)
- Maria Baka
- CPMF2, Flemish Cluster Predictive Microbiology in Foods, Belgium(1); BioTeC+, Chemical and Biochemical Process Technology and Control, Department of Chemical Engineering, KU Leuven, Belgium.
| | - Estefanía Noriega
- CPMF2, Flemish Cluster Predictive Microbiology in Foods, Belgium(1); BioTeC+, Chemical and Biochemical Process Technology and Control, Department of Chemical Engineering, KU Leuven, Belgium.
| | - Kristof Van Langendonck
- BioTeC+, Chemical and Biochemical Process Technology and Control, Department of Chemical Engineering, KU Leuven, Belgium
| | - Jan F Van Impe
- CPMF2, Flemish Cluster Predictive Microbiology in Foods, Belgium(1); BioTeC+, Chemical and Biochemical Process Technology and Control, Department of Chemical Engineering, KU Leuven, Belgium.
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12
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Zalazar AL, Gliemmo MF, Campos CA. Effect of stabilizers, oil level and structure on the growth of Zygosaccharomyces bailii and on physical stability of model systems simulating acid sauces. Food Res Int 2016; 85:200-208. [PMID: 29544836 DOI: 10.1016/j.foodres.2016.04.040] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Revised: 04/26/2016] [Accepted: 04/27/2016] [Indexed: 10/21/2022]
Abstract
The effect of xanthan gum, guar gum, oil and the structure promoted by these compounds on the growth of Zygosaccharomyces bailii and on physical stability of emulsified systems simulating acid sauces was studied. Furthermore, the effect of yeast growth on physical stability of emulsions was also evaluated. Yeast growth was evaluated by plate count and modeled by the modified Gompertz equation. Emulsions characteristics and their stability were determined by droplet size, zeta potential and rheological measurements. The latter was also used to evaluate structure's effect on yeast growth. Physical characteristics of emulsions depended on system composition. Yeasts slightly affected droplet size. Z. bailii growth was satisfactorily modeled by the modified Gompertz equation. The specific growth rate (μm) and the asymptotic value (A) obtained depended on xanthan gum, guar gum and oil content. Furthermore, the structure promoted by these compounds exerted a significant effect on growth. In general, an increase in the solid character and yield stress through the addition of xanthan gum promoted a decrease in A parameter. On the contrary, a decrease in the solid character through the addition of guar gum promoted an increase in the A parameter. The results obtained stressed that stabilizers, oil and their structuring ability play an important role on Z. bailii growth.
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Affiliation(s)
- Aldana L Zalazar
- Departamento de Industrias, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Int. Güiraldes 2160, Ciudad Universitaria (1428), Buenos Aires, Argentina; Consejo Nacional de Investigaciones, Científicas y Técnicas de la República Argentina, Argentina
| | - María F Gliemmo
- Departamento de Industrias, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Int. Güiraldes 2160, Ciudad Universitaria (1428), Buenos Aires, Argentina; Consejo Nacional de Investigaciones, Científicas y Técnicas de la República Argentina, Argentina
| | - Carmen A Campos
- Departamento de Industrias, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Int. Güiraldes 2160, Ciudad Universitaria (1428), Buenos Aires, Argentina; Consejo Nacional de Investigaciones, Científicas y Técnicas de la República Argentina, Argentina.
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13
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Khanipour E, Flint SH, McCarthy OJ, Golding M, Palmer J, Ratkowsky DA, Ross T, Tamplin M. Modelling the combined effects of salt, sorbic acid and nisin on the probability of growth of Clostridium sporogenes in a controlled environment (nutrient broth). Food Control 2016. [DOI: 10.1016/j.foodcont.2015.10.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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14
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Boons K, Noriega E, Verherstraeten N, David CC, Hofkens J, Van Impe JF. The effect of medium structure complexity on the growth of Saccharomyces cerevisiae in gelatin-dextran systems. Int J Food Microbiol 2015; 199:8-14. [PMID: 25621715 DOI: 10.1016/j.ijfoodmicro.2014.12.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Revised: 10/31/2014] [Accepted: 12/14/2014] [Indexed: 11/29/2022]
Abstract
As most food systems are (semi-)solid, the effect of food structure on bacterial growth has been widely acknowledged. However, studies on the growth dynamics of yeasts have neglected the effect of food structure. In this paper, the growth dynamics of the spoilage yeast Saccharomyces cerevisiae was investigated at 23.5 °C in broth, singular, homogeneous biopolymer systems and binary biopolymer systems with a heterogeneous microstructure. The biopolymers gelatin and dextran were used to introduce the different levels of structure. The metabolizing ability of gelatin and dextran by S. cerevisiae was examined. To study microbial behavior in the binary systems at the micro level, mixtures were imaged with confocal laser scanning microscopy (CLSM). Growth dynamics and microscopic images of S. cerevisiae were compared with those obtained for Escherichia coli in the same model system (Boons et al., 2014). Different phase-separated, heterogeneous microstructures were obtained by changing the amount of added gelatin and dextran. Regardless of the microstructure, S. cerevisiae was preferentially located in the dextran phase. Metabolizing ability-tests indicated that gelatin could be consumed by S. cerevisiae but in the presence of glucose, no change in gelatin concentration was observed. No indication of dextran metabolizing ability was observed. When supplementing broth with gelatin or dextran alone, an enhanced growth rate and maximum cell density were observed. This enhancement was further increased by adding a second biopolymer, introducing a heterogeneous microstructure and hence increasing the medium structure complexity. The results obtained indicate that food structure complexity plays a significant role in the growth dynamics of S. cerevisiae, an important food spoiler.
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Affiliation(s)
- Kathleen Boons
- CPMF(2)-Flemish Cluster Predictive Microbiology in Foods, Belgium(1); BioTeC-Chemical and Biochemical Process Technology and Control, Department of Chemical Engineering, KU Leuven, Leuven, Belgium.
| | - Estefanía Noriega
- CPMF(2)-Flemish Cluster Predictive Microbiology in Foods, Belgium(1); BioTeC-Chemical and Biochemical Process Technology and Control, Department of Chemical Engineering, KU Leuven, Leuven, Belgium.
| | - Niels Verherstraeten
- BioTeC-Chemical and Biochemical Process Technology and Control, Department of Chemical Engineering, KU Leuven, Leuven, Belgium.
| | | | - Johan Hofkens
- Molecular Visualization and Photonics, KU Leuven, Leuven, Belgium.
| | - Jan F Van Impe
- CPMF(2)-Flemish Cluster Predictive Microbiology in Foods, Belgium(1); BioTeC-Chemical and Biochemical Process Technology and Control, Department of Chemical Engineering, KU Leuven, Leuven, Belgium.
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15
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Lobete MM, Fernandez EN, Van Impe JFM. Recent trends in non-invasive in situ techniques to monitor bacterial colonies in solid (model) food. Front Microbiol 2015; 6:148. [PMID: 25798133 PMCID: PMC4351626 DOI: 10.3389/fmicb.2015.00148] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Accepted: 02/09/2015] [Indexed: 12/29/2022] Open
Abstract
Planktonic cells typically found in liquid systems, are routinely used for building predictive models or assessing the efficacy of food preserving technologies. However, freely suspended cells often show different susceptibility to environmental hurdles than colony cells in solid matrices. Limited oxygen, water and nutrient availability, metabolite accumulation and physical constraints due to cell immobilization in the matrix, are main factors affecting cell growth. Moreover, intra- and inter-colony interactions, as a consequence of the initial microbial load in solid systems, may affect microbial physiology. Predictive food microbiology approaches are moving toward a more realistic resemblance to food products, performing studies in structured solid systems instead of liquids. Since structured systems promote microbial cells to become immobilized and grow as colonies, it is essential to study the colony behavior, not only for food safety assurance systems, but also for understanding cell physiology and optimizing food production processes in solid matrices. Traditionally, microbial dynamics in solid systems have been assessed with a macroscopic approach by applying invasive analytical techniques; for instance, viable plate counting, which yield information about overall population. In the last years, this approach is being substituted by more mechanistically inspired ones at mesoscopic (colony) and microscopic (cell) levels. Therefore, non-invasive and in situ monitoring is mandatory for a deeper insight into bacterial colony dynamics. Several methodologies that enable high-throughput data collection have been developed, such as microscopy-based techniques coupled with image analysis and OD-based measurements in microplate readers. This research paper provides an overview of non-invasive in situ techniques to monitor bacterial colonies in solid (model) food and emphasizes their advantages and inconveniences in terms of accuracy, performance and output information.
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Affiliation(s)
- María M. Lobete
- Flemish Cluster Predictive Microbiology in Foods, Leuven, Belgium
- Chemical and Biochemical Process Technology and Control, Department of Chemical Engineering, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Estefania Noriega Fernandez
- Flemish Cluster Predictive Microbiology in Foods, Leuven, Belgium
- Chemical and Biochemical Process Technology and Control, Department of Chemical Engineering, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Jan F. M. Van Impe
- Flemish Cluster Predictive Microbiology in Foods, Leuven, Belgium
- Chemical and Biochemical Process Technology and Control, Department of Chemical Engineering, Katholieke Universiteit Leuven, Leuven, Belgium
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16
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Predictive Microbiology. Food Microbiol 2014. [DOI: 10.1128/9781555818463.ch40] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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17
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Khanipour E, Flint SH, McCarthy OJ, Golding M, Palmer J, Tamplin M. Evaluation of the effects of sodium chloride, potassium sorbate, nisin and lysozyme on the probability of growth ofClostridium sporogenes. Int J Food Sci Technol 2013. [DOI: 10.1111/ijfs.12446] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Elham Khanipour
- Institute of Food; Nutrition and Human Health; Massey University; Private Bag 11 222 Palmerston North New Zealand
| | - Steve H. Flint
- Institute of Food; Nutrition and Human Health; Massey University; Private Bag 11 222 Palmerston North New Zealand
| | - Owen J. McCarthy
- Institute of Food; Nutrition and Human Health; Massey University; Private Bag 11 222 Palmerston North New Zealand
| | - Matt Golding
- Institute of Food; Nutrition and Human Health; Massey University; Private Bag 11 222 Palmerston North New Zealand
| | - Jon Palmer
- Institute of Food; Nutrition and Human Health; Massey University; Private Bag 11 222 Palmerston North New Zealand
| | - Mark Tamplin
- Food Safety Centre; Tasmanian Institute of Agriculture; Private Bag 54 Hobart Tas 7001 Australia
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18
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The effect of colony formation on the heat inactivation dynamics of Escherichia coli K12 and Salmonella typhimurium. Food Res Int 2013. [DOI: 10.1016/j.foodres.2013.09.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Boons K, Van Derlinden E, Mertens L, Peeters V, Van Impe JF. Effect of immobilization and salt concentration on the growth dynamics of Escherichia coli K12 and Salmonella typhimurium. J Food Sci 2013; 78:M567-74. [PMID: 23464757 DOI: 10.1111/1750-3841.12067] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Accepted: 01/06/2013] [Indexed: 11/29/2022]
Abstract
Up to now, it is generally observed that (i) the microbial growth domain is confined by structure-induced stress, or (ii) a solid(-like) environment can enhance microbial survival/growth. In most studies in solid(-like) systems, structure is induced by the addition of gelatin. The aim of this study was to evaluate the effect of other structure-inducing components on the growth dynamics. Both single and binary gel systems are used. Growth is studied when simultaneously exposed to salt stress. Experiments are performed in spectrophotometer tubes, filled with 1 mL of liquid, or structured inoculated brain heart infusion. Four different (combinations of) gelling agents are tested, that is, gelatin, xanthan gum, a 50% combination of xanthan gum and gelatin, and a 50% combination of carrageenan and gelatin. Experiments determine the growth behavior of both Escherichia coli (0% to 0.5% and 1%, 2%, 3%, 4%, and 5% NaCl) and Salmonella Typhimurium (0%, 1%, 2%, 3%, 4%, and 5% NaCl) at 23.5 and 27 °C. By means of plate counting, the growth dynamics are determined. At the studied conditions, growth of E. coli and Salmonella Typhimurium seems independent of the type of structure-inducing component. However, at higher concentrations of salt (>2%), lag phases are typically shorter in solid(-like) systems than in liquid media. For the conditions tested, the effect of a structured environment on growth rate and maximal cell density can be neglected.
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Affiliation(s)
- Kathleen Boons
- Chemical and Biochemical Process Technology and Control (BioTeC), KU Leuven W. de Croylaan 46, B-3001 Leuven, Belgium
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Behavior of Escherichia coli in a heterogeneous gelatin-dextran mixture. Appl Environ Microbiol 2013; 79:3126-8. [PMID: 23435888 DOI: 10.1128/aem.03782-12] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In a gelatin-dextran mixture, changing the (relative and/or absolute) concentration of the components leads to the formation of different microstructures. Confocal laser scanning microscopy illustrated that the nature of the microstructure determines the location and morphology of Escherichia coli colonies. Observations indicate that bacterial growth preferentially occurs in the dextran phase, regardless of the microstructure.
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Mertens L, Van Derlinden E, Van Impe JF. Comparing experimental design schemes in predictive food microbiology: Optimal parameter estimation of secondary models. J FOOD ENG 2012. [DOI: 10.1016/j.jfoodeng.2012.03.018] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Mertens L, Van Derlinden E, Van Impe JF. A novel method for high-throughput data collection in predictive microbiology: optical density monitoring of colony growth as a function of time. Food Microbiol 2012; 32:196-201. [PMID: 22850393 DOI: 10.1016/j.fm.2012.04.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2011] [Revised: 03/05/2012] [Accepted: 04/03/2012] [Indexed: 11/26/2022]
Abstract
Recently, the focus of predictive food microbiology has shifted towards more mechanistically-inspired modelling. Together with this trend, the need for methods that allow rapid data collection at the (intra)cellular level, as well as the intermediate subpopulation/colony level, has emerged. Although several experimental techniques are currently available to study colony dynamics in/on solid media, their widespread implementation as high-throughput methods remains a challenge. In this research, a novel method is presented to study colony growth based on optical density measurements performed in microtiter plates. An area scan procedure was applied to monitor individual Escherichia coli colonies in 48-well plates at 30 °C. Based on a fixed threshold value to separate the object (colony) from the background, the colony area was determined as a function of time. With this technique, expansion of the colony in radial direction could be monitored. Practical limitations (i.e., maximum achievable resolution and colony size) of the proposed method were investigated. A comparison was made with existing methods at the level of hardware requirements, data acquisition and data processing. Overall, the novel optical density method proved to be a flexible, high-throughput tool for monitoring (the mechanisms of) microbial colony growth in solid(like) systems.
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Affiliation(s)
- Laurence Mertens
- CPMF(2) - Flemish Cluster Predictive Microbiology in Foods, Belgium
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