Effect of the substrate's microstructure on the growth of Listeria monocytogenes

Aspridou, Zafiro; Moschakis, Thomas; Βiliaderis, Costas G.; Koutsoumanis, Kostas

doi:10.1016/j.foodres.2014.07.031

Cited by 31 publications

(45 citation statements)

References 49 publications

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“…This seems to corroborate the results found by rheological measurements, which indicated some changes on the structure of the omelette treated at 100ºC. Aspridou et al (2014) studied the effect of the microstructure of the medium on the growth of Listeria monocytogenes. They reported that the growth of the pathogen was faster in the liquid than in the gelled systems.…”

Section: Development Of Staphylococcus During Storagesupporting

confidence: 87%

Survival and development of Staphylococcus in egg products

Sánchez

Neira

Laca

et al. 2019

LWT

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In this work, Staphylococcus has been employed to simulate a contamination of different egg foodstuffs. Liquid (egg white, egg yolk and whole egg) and also solid (Spanish potato omelette) products have been employed as model foods. The effect of different parameters, i.e. oxygen availability, cooking temperature and storage temperature, on microorganism survival and development has been evaluated. In addition, the structure of solid foods has been analysed by means of rheological measurements. Results showed that Staphylococcus behaviour in liquid media was strongly influenced by the oxygen concentration, which is determinant for the specific growth rates (μ). In solid foods, the increase of cooking temperature to 100ºC reduced the microbial viability by one order of magnitude with respect to the raw foodstuff. Additionally, it was observed that the structure of the omelette, which depended on the cooking temperature, was a key parameter regarding the μ values. Therefore, to avoid the risk of food poisoning by Staphylococcus proliferation, in the case of egg products cooked only for few minutes, the cooking temperature should be higher than 100ºC and *Manuscript Click here to view linked References 2 the subsequent storage should be at refrigeration temperatures that increase the lag phase and decrease the growth rate.

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Section: Development Of Staphylococcus During Storagesupporting

confidence: 87%

Survival and development of Staphylococcus in egg products

Sánchez

Neira

Laca

et al. 2019

LWT

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“…In general, these differences between the growth morphologies are limited for most temperatures and planktonic cells and colonies present similar maximum specific growth rates. This is in contrast with most literature addressing the growth dynamics of planktonic cultures and surface and/or immersed colonies, where the main observation with respect to the maximum specific growth rate is the following: μ planktonic ≥ μ immersed ≥ μ surface (see, e.g., Aspridou et al, 2014;Brocklehurst et al, 1997;Meldrum et al, 2003;Theys et al, 2008). In the work of Brocklehurst et al (1997) and Meldrum et al (2003), this effect was observed for S. Typhimurium and L. monocytogenes, for different concentrations of salt, sucrose (or a w ) or several pH values.…”

Section: Maximum Specific Growth Ratementioning

confidence: 72%

“…Theys et al (2008) observed that the addition of 1% and 5% (w/v) gelatin resulted in a significant reduction of the growth rate of S. Typhimurium at 20.0°C for a certain pH and a w range, including those values used for S. Typhimurium in this study. Aspridou et al (2014) studied the growth dynamics of L. monocytogenes in liquid substrates and gels of sodium alginate and gelatin at different temperatures. Growth in gels proved to be slower than for the liquid systems with a most pronounced effect at low temperatures, indicating a more significant effect of the microstructure at these low temperatures.…”

Section: Maximum Specific Growth Ratementioning

confidence: 99%

“…On the other hand, some research groups have focused more on obtaining fundamental knowledge about food (microstructure) and colony dynamics in food model systems (Antwi et al, 2006;Aspridou et al, 2014;Boons et al, 2014;Mertens et al, 2012;Noriega et al, 2010b;Stecchini et al, 1998Stecchini et al, , 2004Theys et al, 2008), the effect of solid structure for both growth kinetics (Lebert et al, 1998;Skandamis et al, 2007;Stecchini et al, 1998) and the probability of growth of certain pathogens, such as Listeria monocytogenes (Koutsoumanis et al, 2004). The difference in growth behavior compared to a liquid system suggests that growth in solid systems may not be well predicted by models derived from liquid systems (Brocklehurst et al, 1997).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Effect of cell immobilization on the growth dynamics of Salmonella Typhimurium and Escherichia coli at suboptimal temperatures

Smet

Derlinden

Mertens

et al. 2015

International Journal of Food Microbiology

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Predictive microbiology has recently acknowledged the impact of the solid(like) food structure on microbial behavior. The presence of this solid(like) structure causes microorganisms to grow as colonies and no longer planktonically as in liquid. In this paper, the growth dynamics of Salmonella Typhimurium and Escherichia coli were studied as a function of temperature, considering different growth morphologies, i.e., (i) planktonic cells, (ii) immersed colonies and (iii) surface colonies. For all three growth morphologies, both microorganisms were grown in petri dishes. While E. coli was grown under optimal pH and water activity (aw), for S. Typhimurium pH and aw were adapted to 5.5 and 0.990. In order to mimic a solid(like) environment, 5% (w/v) gelatin was added. All petri dishes were incubated under static conditions at temperatures in the range [8.0°C-22.0°C]. Cell density was determined via viable plate counting. This work demonstrates that the growth morphology (planktonic vs. colony) has a negligible effect on the growth dynamics as a function of temperature. The observation of almost equal growth rates for planktonic cultures and colonies is in contrast to literature where, mostly, a difference is observed, i.e., μplanktonic cells≥μimmersed colonies≥μsurface colonies. This difference might be due to shaking of the liquid culture in these studies, which results in a nutrient and oxygen rich environment, in contrast to the diffusion-limited gel system. Experiments also indicate that lag phases for solid(like) systems are similar to those for the planktonic cultures, as can be found in literature for similar growth conditions. Considering the maximum cell density, no clear trend was deducted for either of the microorganisms. This study indicates that the growth parameters in the suboptimal temperature range do not depend on the growth morphology. For the considered experimental conditions, models previously developed for liquid environments can be used for solid(like) systems.

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“…If bacteria are growing in structured aqueous phase, e.g., due to addition of thickeners, or gelling (structure-inducing) agents, such as gelatin, pectins, starch, gums, etc., microbial cells are immobilized within the gelled regions and constrained to grow as submerged colonies in three dimensions. Their growth rates as colonies tend to be lower than that of planktonically growing cells (Wilson et al, 2002 ; Theys et al, 2008 ; Boons et al, 2013a , b , 2014 ; Aspridou et al, 2014 ). This can be further enhanced by increasing the fat concentration on the expense of water phase, thereby increasing the size of oil droplets with concomitant trend of reversal of oil-in-water emulsion.…”

Section: Model Types and Classificationmentioning

confidence: 99%

Colonial vs. planktonic type of growth: mathematical modeling of microbial dynamics on surfaces and in liquid, semi-liquid and solid foods

Skandamis

Jeanson

2015

Front. Microbiol.

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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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Effect of the substrate's microstructure on the growth of Listeria monocytogenes

Cited by 31 publications

References 49 publications

Survival and development of Staphylococcus in egg products

Survival and development of Staphylococcus in egg products

Effect of cell immobilization on the growth dynamics of Salmonella Typhimurium and Escherichia coli at suboptimal temperatures

Colonial vs. planktonic type of growth: mathematical modeling of microbial dynamics on surfaces and in liquid, semi-liquid and solid foods

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