Model for combined effect of temperature and salt concentration/water activity on the growth rate of <i>Staphylococcus xylosus</i>

McMeekin, TA; Chandler, R. E.; Doe, P. E.; Garland, C. D.; Olley, June; Putro, Sapto P.; Ratkowsky, David A.

doi:10.1111/j.1365-2672.1987.tb02687.x

Cited by 184 publications

(82 citation statements)

References 7 publications

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“…This may indicate that adding NaCl to the growth medium interferes with the efficiency of the substrate conversion into biomass for the latter strain. A linear decrease in the growth rate with a w values below the optimum is usually observed (46,53).…”

Section: Discussionmentioning

confidence: 99%

“…To determine whether the effect of the added NaCl was due solely to a reduction in a w , an additional fermentation was carried out in the presence of 9.9% (wt/vol) glycerol (sterilized separately) in the absence of added salt. Based on extrapolation of data from previous studies (12,46), addition of 9.9% (wt/vol) glycerol to the basal growth medium should result in the same decrease in a w as addition of approximately 4% (wt/vol) NaCl (42).…”

Section: Methodsmentioning

confidence: 99%

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Sodium Chloride Reduces Production of Curvacin A, a Bacteriocin Produced by Lactobacillus curvatus Strain LTH 1174, Originating from Fermented Sausage

Verluyten

Messens

Vuyst

2004

Appl Environ Microbiol

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Lactobacillus curvatus LTH 1174, a strain originating in fermented sausage, produces the antilisterial bacteriocin curvacin A. Its biokinetics of cell growth and bacteriocin production as a function of various concentrations of salt (sodium chloride) were investigated in vitro during laboratory fermentations using modified MRS medium. A model was set up to describe the effects of different NaCl concentrations on microbial behavior. Both cell growth and bacteriocin activity were affected by changes in the salt concentration. Sodium chloride clearly slowed down the growth of L. curvatus LTH 1174, but more importantly, it had a detrimental effect on specific curvacin A production (k B ) and hence on overall bacteriocin activity. Even a low salt concentration (2%, wt/vol) decreased bacteriocin production, while growth was unaffected at this concentration. The inhibitory effect of NaCl was mainly due to its role as an a w -lowering agent. Further, it was clear that salt interfered with bacteriocin induction. Additionally, when 6% (wt/vol) sodium chloride was added, the minimum biomass concentration necessary to start the production of curvacin A (X B ) was 0.90 g (cell dry mass) per liter. Addition of the cell-free culture supernatant or a protein solution as a source of induction factor resulted in a decrease in X B , an increase in k B , and hence an increase in the maximum attainable bacteriocin activity.

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Sodium Chloride Reduces Production of Curvacin A, a Bacteriocin Produced by Lactobacillus curvatus Strain LTH 1174, Originating from Fermented Sausage

Verluyten

Messens

Vuyst

2004

Appl Environ Microbiol

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“…Relatively few models are available in the literature that incorporate the parameter a w or the concentration of a w -lowering solutes. Where this was the case, model 1 was predominantly used (17,23,26,28,31,38). However, many undissociated acid concentration models could be interpreted as a w -lowering solute models and were of equal performance as their original a w models.…”

Section: Discussionmentioning

confidence: 99%

Comparing Nonsynergy Gamma Models and Interaction Models To Predict Growth of Emetic Bacillus cereus for Combinations of pH and Water Activity Values

Biesta-Peters

Reij

Zwietering

et al. 2011

Appl Environ Microbiol

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This research aims to test the absence (gamma hypothesis) or occurrence of synergy between two growth-limiting factors, i.e., pH and water activity (a w ), using a systematic approach for model selection. In this approach, preset criteria were used to evaluate the performance of models. Such a systematic approach is required to be confident in the correctness of the individual components of the combined (synergy) models. With Bacillus cereus F4810/72 as the test organism, estimated growth boundaries for the a w -lowering solutes NaCl, KCl, and glucose were 1.13 M, 1.13 M, and 1.68 M, respectively. The accompanying a w values were 0.954, 0.956, and 0.961, respectively, indicating that equal a w values result in similar effects on growth. Out of the 12 models evaluated using the preset criteria, the model of J. H. T. Luong (Biotechnol. Bioeng. 27:280-285, 1985) was the best model to describe the effect of a w on growth. This a w model and the previously selected pH model were combined into a gamma model and into two synergy models. None of the three models was able to describe the combined pH and a w conditions sufficiently well to satisfy the preset criteria. The best matches between predicted and experimental data were obtained with the No combination of models that was able to predict the impact of both individual and combined hurdles correctly could be found. Consequently, in this case we could not prove the existence of synergy nor falsify the gamma hypothesis.The microorganism Bacillus cereus is associated with food spoilage as well as food poisoning (1, 34). The spores formed by B. cereus generally will resist treatments used to prolong the shelf life of food. Viable spores present in a food product may germinate, and the vegetative cells can subsequently grow if conditions are favorable, leading to spoilage of the food product (9, 14, 18). Several growth-limiting factors, collectively referred to as hurdles, can be used to ensure food stability and safety. Examples of such hurdles are low pH, low water activity (a w ), and low temperature (12). Combining hurdles to achieve food stability and safety, known as hurdle technology, can be used to achieve an overall level of protection in food while minimizing detrimental impacts on food quality (19).Improved quantification of the combined impact of hurdles on growth of microorganisms is an ongoing endeavor, but there are different views of how antimicrobial factors combine. One view is that there are interactive effects between hurdles. When combinations of hurdles are used, they might give significantly greater protection than expected on the basis of the application of the individual hurdles, so called synergy (19). The other view follows the gamma hypothesis (39) in which there is no synergy, but inhibitory environmental factors combine in a multiplicative manner to produce the observed overall microbial inhibition. Evidently, it is important in the selection of hurdles to know whether either the gamma hypothesis is valid or synergy occurs between factors. A...

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“…This species has also been identified as the most abundant species of Staphylococcus in other raw-cured meat products made from whole pieces (Von Reinbaben and Seipp, 1986;Molina et al, 1989;Carrascosa and Cornejo, 1991;Cornejo and Carrascosa, 1991;Rodríguez et al, 1994) and in fermented sausages (Seager et al, 1986;Coppola et al, 2000;Cocolin et al, 2001;Papamanoli et al, 2002;Rantsiou et al, 2005;Martín et al, 2006;García Fontán et al, 2007b;Martín et al, 2007). This species is, in fact, one of the most resistant to unfavourable environmental conditions (McMeekin et al, 1987;Chandler and McMeekin, 1989). Staphylococcus xylosus is also one of the most genetically variable microbial species, which may lead to the existence of diverse biotypes with different phenotypic characteristics (Kloos, 1980); this phenomenon may be due to the capacity of this species to adapt to different environmental conditions (Rodríguez Jovita, 1997).…”

Section: Species Isolated Throughout the Manufacturing Processmentioning

confidence: 99%

Study of the Micrococcaceae and Staphylococcaceae throughout the Manufacture of Dry-Cured Lacón (a Spanish Traditional Meat Product) Made without or with Additives

Lorenzo¹,

Fontán²,

Gómez³

et al. 2012

JFR

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Micrococcaceae and Staphylococcaceae were enumerated (on SPC agar + 7.5% NaCl) in samples from the surface and the interior of pieces of dry-cured lacón (a Spanish traditional meat product), at different stages of the manufacturing process, and from six different batches (three made without and three with additives -glucose, sodium nitrite, sodium nitrate, sodium ascorbate, and sodium citrate-). The use of additives did not affect the counts or evolution of this microbial group.For four batches (two without and two with additives), a total of 335 strains were isolated and identified by classical methods.Staphylococcus xylosus was the most abundant and constant species throughout manufacture of the batches made without and with additives. Other species of staphylococci were isolated, including: Staph. equorum, Staph. sciuri, Staph. gallinarum, Staph. cohnii, Staph. intermedius, Staph. capitis, Staph. epidermidis, Staph. simulans and Staph. warneri

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Model for combined effect of temperature and salt concentration/water activity on the growth rate of Staphylococcus xylosus

Cited by 184 publications

References 7 publications

Sodium Chloride Reduces Production of Curvacin A, a Bacteriocin Produced by Lactobacillus curvatus Strain LTH 1174, Originating from Fermented Sausage

Sodium Chloride Reduces Production of Curvacin A, a Bacteriocin Produced by Lactobacillus curvatus Strain LTH 1174, Originating from Fermented Sausage

Comparing Nonsynergy Gamma Models and Interaction Models To Predict Growth of Emetic Bacillus cereus for Combinations of pH and Water Activity Values

Study of the Micrococcaceae and Staphylococcaceae throughout the Manufacture of Dry-Cured Lacón (a Spanish Traditional Meat Product) Made without or with Additives

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