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Skandamis PN, Jeanson S. Colonial vs. planktonic type of growth: mathematical modeling of microbial dynamics on surfaces and in liquid, semi-liquid and solid foods. Front Microbiol 2015; 6:1178. [PMID: 26579087 PMCID: PMC4625091 DOI: 10.3389/fmicb.2015.01178] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 10/12/2015] [Indexed: 01/09/2023] Open
Abstract
Predictive models are mathematical expressions that describe the growth, survival, inactivation, or biochemical processes of foodborne bacteria. During processing of contaminated raw materials and food preparation, bacteria are entrapped into the food residues, potentially transferred to the equipment surfaces (abiotic or inert surfaces) or cross-contaminate other foods (biotic surfaces). Growth of bacterial cells can either occur planktonically in liquid or immobilized as colonies. Colonies are on the surface or confined in the interior (submerged colonies) of structured foods. For low initial levels of bacterial population leading to large colonies, the immobilized growth differs from planktonic growth due to physical constrains and to diffusion limitations within the structured foods. Indeed, cells in colonies experience substrate starvation and/or stresses from the accumulation of toxic metabolites such as lactic acid. Furthermore, the micro-architecture of foods also influences the rate and extent of growth. The micro-architecture is determined by (i) the non-aqueous phase with the distribution and size of oil particles and the pore size of the network when proteins or gelling agent are solidified, and by (ii) the available aqueous phase within which bacteria may swarm or swim. As a consequence, the micro-environment of bacterial cells when they grow in colonies might greatly differs from that when they grow planktonically. The broth-based data used for modeling (lag time and generation time, the growth rate, and population level) are poorly transferable to solid foods. It may lead to an over-estimation or under-estimation of the predicted population compared to the observed population in food. If the growth prediction concerns pathogen bacteria, it is a major importance for the safety of foods to improve the knowledge on immobilized growth. In this review, the different types of models are presented taking into account the stochastic behavior of single cells in the growth of a bacterial population. Finally, the recent advances in the rules controlling different modes of growth, as well as the methodological approaches for monitoring and modeling such growth are detailed.
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Affiliation(s)
- Panagiotis N Skandamis
- Laboratory of Food Quality Control and Hygiene, Department of Food Science and Human Nutrition, University of Athens Athens, Greece
| | - Sophie Jeanson
- Institut National de la Recherche Agronomique, UMR1253 Science and Technology of Milk and Eggs Rennes, France ; AGROCAMPUS OUEST, UMR1253 Science and Technology of Milk and Eggs Rennes, France
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Bragazzi NL, Gasparini R, Amicizia D, Panatto D, Larosa C. Porous Alumina as a Promising Biomaterial for Public Health. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2015; 101:213-29. [PMID: 26572980 DOI: 10.1016/bs.apcsb.2015.08.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Porous aluminum is a nanostructured material characterized by unique properties, such as chemical stability, regular uniformity, dense hexagonal porous lattice with high aspect ratio nanopores, excellent mechanical strength, and biocompatibility. This overview examines how the structure and properties of porous alumina can be exploited in the field of public health. Porous alumina can be employed for fabricating membranes and filters for bioremediation, water ultrafiltration, and microfiltration/nanofiltration, being a promising technique for having clean and fresh water, which is essential for human health. Porous alumina-based nanobiosensor coated with specific antibodies or peptides seem to be a useful tool to detect and remove pathogens both in food and in water, as well as for environmental monitoring. Further, these applications, being low-energy demanding and cost-effective, are particularly valuable in resource-limited settings and contexts, and can be employed as point of use devices in developing countries, where there is an urgent need of hygiene and safety assurance.
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Affiliation(s)
- Nicola Luigi Bragazzi
- Department of Health Sciences (DISSAL), Via Antonio Pastore 1, University of Genoa, Genoa, Italy
| | - Roberto Gasparini
- Department of Health Sciences (DISSAL), Via Antonio Pastore 1, University of Genoa, Genoa, Italy.
| | - Daniela Amicizia
- Department of Health Sciences (DISSAL), Via Antonio Pastore 1, University of Genoa, Genoa, Italy
| | - Donatella Panatto
- Department of Health Sciences (DISSAL), Via Antonio Pastore 1, University of Genoa, Genoa, Italy
| | - Claudio Larosa
- Department of Surgical Sciences and Integrated Diagnostics, University of Genoa, Genoa, Italy
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Warda AK, den Besten HMW, Sha N, Abee T, Nierop Groot MN. Influence of food matrix on outgrowth heterogeneity of heat damaged Bacillus cereus spores. Int J Food Microbiol 2015; 201:27-34. [PMID: 25727186 DOI: 10.1016/j.ijfoodmicro.2015.02.010] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Revised: 01/20/2015] [Accepted: 02/02/2015] [Indexed: 11/26/2022]
Abstract
Spoilage of heat treated foods can be caused by the presence of surviving spore-formers. It is virtually impossible to prevent contamination at the primary production level as spores are ubiquitous present in the environment and can contaminate raw products. As a result spore inactivation treatments are widely used by food producing industries to reduce the microbial spore loads. However consumers prefer mildly processed products that have less impact on its quality and this trend steers industry towards milder preservation treatments. Such treatments may result in damaged instead of inactivated spores, and these spores may germinate, repair, and grow out, possibly leading to quality and safety issues. The ability to repair and grow out is influenced by the properties of the food matrix. In the current communication we studied the outgrowth from heat damaged Bacillus cereus ATCC 14579 spores on Anopore membrane, which allowed following outgrowth heterogeneity of individual spores on broccoli and rice-based media as well as standard and mildly acidified (pH 5.5) meat-based BHI. Rice, broccoli and BHI pH 5.5 media resulted in delayed outgrowth from untreated spores, and increased heterogeneity compared to BHI pH 7.4, with the most pronounced effect in rice media. Exposure to wet heat for 1 min at 95 °C caused 2 log inactivation and approximately 95% of the spores in the surviving fraction were damaged resulting in substantial delay in outgrowth based on the time required to reach a maximum microcolony size of 256 cells. The delay was most pronounced for heat-treated spores on broccoli medium followed by spores on rice media (both untreated and treated). Interestingly, the increase in outgrowth heterogeneity of heat treated spores on BHI pH 7.4 was more pronounced than on rice, broccoli and BHI pH 5.5 conceivably reflecting that conditions in BHI pH 7.4 better support spore damage repair. This study compares the effects of three main factors, namely heat treatment, pH of BHI and the effect of food matrix highlighting the impact of different (model) food recovery media on outgrowth efficiency and heterogeneity of non-heat-treated and heat-damaged B. cereus spores.
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Affiliation(s)
- Alicja K Warda
- TI Food and Nutrition, Wageningen, The Netherlands; Laboratory of Food Microbiology, Wageningen University, Wageningen, The Netherlands; Food & Biobased Research, Wageningen UR, Wageningen, The Netherlands
| | - Heidy M W den Besten
- Laboratory of Food Microbiology, Wageningen University, Wageningen, The Netherlands
| | - Na Sha
- Laboratory of Food Microbiology, Wageningen University, Wageningen, The Netherlands
| | - Tjakko Abee
- TI Food and Nutrition, Wageningen, The Netherlands; Laboratory of Food Microbiology, Wageningen University, Wageningen, The Netherlands.
| | - Masja N Nierop Groot
- TI Food and Nutrition, Wageningen, The Netherlands; Food & Biobased Research, Wageningen UR, Wageningen, The Netherlands
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Yagur-Kroll S, Schreuder E, Ingham CJ, Heideman R, Rosen R, Belkin S. A miniature porous aluminum oxide-based flow-cell for online water quality monitoring using bacterial sensor cells. Biosens Bioelectron 2015; 64:625-32. [DOI: 10.1016/j.bios.2014.09.076] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Revised: 09/23/2014] [Accepted: 09/25/2014] [Indexed: 10/24/2022]
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Inactivation of Lactobacillus plantarum WCFS1 during spray drying and storage assessed with complementary viability determination methods. Food Res Int 2014; 64:212-217. [DOI: 10.1016/j.foodres.2014.06.029] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Revised: 06/16/2014] [Accepted: 06/17/2014] [Indexed: 11/21/2022]
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van Melis CCJ, den Besten HMW, Nierop Groot MN, Abee T. Quantification of the impact of single and multiple mild stresses on outgrowth heterogeneity of Bacillus cereus spores. Int J Food Microbiol 2014; 177:57-62. [PMID: 24607860 DOI: 10.1016/j.ijfoodmicro.2014.02.015] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Revised: 02/13/2014] [Accepted: 02/17/2014] [Indexed: 11/19/2022]
Abstract
Outgrowth heterogeneity of bacterial spore populations complicates both prediction and efficient control of spore outgrowth. In this study, the impact of mild preservation stresses on outgrowth of Bacillus cereus ATCC 14579 spores was quantified during the first stages of outgrowth. Heterogeneity in outgrowth of heat-treated (90°C for 10 min) and non-heat-treated germinated single spores to the maximum micro-colony stage of 256 cells was assessed by direct imaging on Anopore strips, placed on BHI plates at pH7 and pH5.5, without and with added NaCl or sorbic acid (HSA). At pH7 non-heated and heat-treated germinated spores required 6h to reach the maximum microcolony stage with limited heterogeneity, and these parameters were only slightly affected with both types of spores when incubated at pH7 with added NaCl. Notably, the most pronounced effects were observed during outgrowth of spores at pH5.5 without and with added NaCl or HSA. Non-heat-treated germinated spores showed again efficient outgrowth with limited heterogeneity reaching the maximum microcolony stage after 6h at pH5.5, which increased to 12h and 16 h with added NaCl and HSA, respectively. In contrast, heat-treated spores displayed a strong delay between initial germination and swelling and further outgrowth at pH5.5, resulting in large heterogeneity and low numbers of fastest growers reaching the maximum microcolony stage after 10, 12 and 24h, without and with added NaCl or HSA, respectively. This work shows that Anopore technology provides quantitative information on the impact of combined preservation stresses on outgrowth of single spores, showing that outgrowth of germinated heat-treated spores is significantly affected at pH5.5 with a large fraction of spores arrested in the early outgrowth stage, and with outgrowing cells showing large heterogeneity with only a small fraction committed to relatively fast outgrowth.
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Affiliation(s)
- C C J van Melis
- Top Institute Food and Nutrition, Nieuwe Kanaal 9A, 6709 PA, Wageningen, The Netherlands; Food Microbiology Laboratory, Wageningen University, Bornse Weilanden 9, 6708 WG, Wageningen, The Netherlands
| | - H M W den Besten
- Food Microbiology Laboratory, Wageningen University, Bornse Weilanden 9, 6708 WG, Wageningen, The Netherlands
| | - M N Nierop Groot
- Top Institute Food and Nutrition, Nieuwe Kanaal 9A, 6709 PA, Wageningen, The Netherlands; Food and Biobased Research, Wageningen University & Research Centre, Bornse Weilanden 9, 6708 WG, Wageningen, The Netherlands
| | - T Abee
- Top Institute Food and Nutrition, Nieuwe Kanaal 9A, 6709 PA, Wageningen, The Netherlands; Food Microbiology Laboratory, Wageningen University, Bornse Weilanden 9, 6708 WG, Wageningen, The Netherlands.
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Oxygen relieves the CO2 and acetate dependency of Lactobacillus johnsonii NCC 533. PLoS One 2013; 8:e57235. [PMID: 23468944 PMCID: PMC3582564 DOI: 10.1371/journal.pone.0057235] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2012] [Accepted: 01/18/2013] [Indexed: 11/19/2022] Open
Abstract
Oxygen relieves the CO2 and acetate dependency of Lactobacillus johnsonii NCC 533. The probiotic Lactobacillus johnsonii NCC 533 is relatively sensitive to oxidative stress; the presence of oxygen causes a lower biomass yield due to early growth stagnation. We show however that oxygen can also be beneficial to this organism as it relieves the requirement for acetate and CO2 during growth. Both on agar- and liquid-media, anaerobic growth of L. johnsonii NCC 533 requires CO2 supplementation of the gas phase. Switching off the CO2 supply induces growth arrest and cell death. The presence of molecular oxygen overcomes the CO2 dependency. Analogously, L. johnsonii NCC 533 strictly requires media with acetate to sustain anaerobic growth, although supplementation at a level that is 100-fold lower (120 microM) than the concentration in regular growth medium for lactobacilli already suffices for normal growth. Analogous to the CO2 requirement, oxygen supply relieves this acetate-dependency for growth. The L. johnsonii NCC 533 genome indicates that this organism lacks genes coding for pyruvate formate lyase (PFL) and pyruvate dehydrogenase (PDH), both CO2 and acetyl-CoA producing systems. Therefore, C1- and C2- compound production is predicted to largely depend on pyruvate oxidase activity (POX). This proposed role of POX in C2/C1-generation is corroborated by the observation that in a POX deficient mutant of L. johnsonii NCC 533, oxygen is not able to overcome acetate dependency nor does it relieve the CO2 dependency.
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Impact of sorbic acid on germination and outgrowth heterogeneity of Bacillus cereus ATCC 14579 spores. Appl Environ Microbiol 2012; 78:8477-80. [PMID: 23001664 DOI: 10.1128/aem.02361-12] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Population heterogeneity complicates the predictability of the outgrowth kinetics of individual spores. Flow cytometry sorting and monitoring of the germination and outgrowth of single dormant spores allowed the quantification of acid-induced spore population heterogeneity at pH 5.5 and in the presence of sorbic acid. This showed that germination efficiency was not a good predictor for heterogeneity in final outgrowth.
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Ingham CJ, ter Maat J, de Vos WM. Where bio meets nano: the many uses for nanoporous aluminum oxide in biotechnology. Biotechnol Adv 2011; 30:1089-99. [PMID: 21856400 DOI: 10.1016/j.biotechadv.2011.08.005] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2011] [Revised: 07/28/2011] [Accepted: 08/03/2011] [Indexed: 01/17/2023]
Abstract
Porous aluminum oxide (PAO) is a ceramic formed by an anodization process of pure aluminum that enables the controllable assembly of exceptionally dense and regular nanopores in a planar membrane. As a consequence, PAO has a high porosity, nanopores with high aspect ratio, biocompatibility and the potential for high sensitivity imaging and diverse surface modifications. These properties have made this unusual material attractive to a disparate set of applications. This review examines how the structure and properties of PAO connect with its present and potential uses within research and biotechnology. The role of PAO is covered in areas including microbiology, mammalian cell culture, sensitive detection methods, microarrays and other molecular assays, and in creating new nanostructures with further uses within biology.
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