A fuzzy logic-based model for the multistage high-pressure inactivation of ssp. MG 1363

Kilimann, K.V.; Hartmann, C.; Delgado, Antonio; Vogel, Rudi F.; Gänzle, Michael G.

doi:10.1016/j.ijfoodmicro.2004.05.010

Cited by 33 publications

(19 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Suppression of F 1 F 0 -ATPase by HPP has been observed in Lactobacillus plantarum (Wouters et al, 1998) and the genes downregulated in this study encode subunits (c, e and c chains) that perform the integral proton translocation step that has been observed to be inhibited in Enterococcus hirae under mild HPP treatments (Marquis & Bender, 1987). No previous specific molecular-based study has shown that HPP diminishes catabolic gene expression; however, physiological studies have demonstrated that metabolic activity clearly declines (Abe et al, 1999;Ulmer et al, 2000;Kilimann et al, 2005) and cell maintenance energy requirements increase (Bothun et al, 2004). Cell maintenance energy essentially includes any energy consumption that is required to maintain an energized cell membrane, repair cellular components, transport substances in and out of the cell and support cell functions such as motility.…”

Section: Effects Of Hpp On Translation-apparatus-related Genesmentioning

confidence: 99%

“…It was concluded that although cell viability was lost, HPP-treated cells were sublethally injured and were potentially capable of recovery back to culturability (Ritz et al, 2006). Physiological studies have also demonstrated that increasing HPP pressure levels results in metabolic indicators (for example the activity of the LmrP membrane transporter) exhibiting an accelerated decline (Kilimann et al, 2005). Over the last several years a number of studies have shown L. monocytogenes and other bacteria such as E. coli seem to be capable of recovering culturability following HPP exposure Bull et al, 2005;Jantzen et al, 2006;Ritz et al, 2006).…”

mentioning

confidence: 99%

See 1 more Smart Citation

Differential gene expression of Listeria monocytogenes during high hydrostatic pressure processing

2008

View full text Add to dashboard Cite

High hydrostatic pressure processing (HPP) is currently being used as a treatment for certain foods to control the presence of food-borne pathogens, such as Listeria monocytogenes. Genomic microarray analysis was performed to determine the effects of HPP on L. monocytogenes in order to understand how it responds to mechanical stress injury. Reverse transcriptase PCR analysis of tufA and rpoC indicated that the reduction of mRNA expression in HPP-treated cells was dependent on intensity and time of the treatment. Treatments of 400 and 600 MPa for 5 min on cells in the exponential growth phase, though leading to partial or complete cellular inactivation, still resulted in measurable relative differential gene expression. Gene set enrichment analysis indicated that HPP induced increased expression of genes associated with DNA repair mechanisms, transcription and translation protein complexes, the septal ring, the general protein translocase system, flagella assemblage and chemotaxis, and lipid and peptidoglycan biosynthetic pathways. On the other hand, HPP appears to suppress a wide range of energy production and conversion, carbohydrate metabolism and virulence-associated genes accompanied by strong suppression of the SigB and PrfA regulons. HPP also affected genes controlled by the pleotrophic regulator CodY. HPP-induced cellular damage appears to lead to increased expression of genes linked to sections of the cell previously shown in bacteria to be damaged or altered during HPP exposure and suppression of gene expression associated with cellular growth processes and virulence.Listeria monocytogenes is a Gram-positive, non-sporulating, rod-shaped, facultative anaerobe that is a member of the phylum Firmicutes and causes the disease listeriosis. Listeriosis is an uncommon but very serious condition that has a high mortality rate amongst susceptible individuals and is acquired orally through the consumption of food (Khelef et al., 2006). Due to its environmentally robust and persistent nature, the control and elimination of L. monocytogenes currently remains a challenge and a priority for the food industry (Bell & Kyriakides, 2005), especially considering the increasing consumer demand for convenience foods that often have varied and minimal conventional post-lethality processing treatments. This concern has led to various technologydriven innovations in food processing, including the application of thermal and non-thermal high hydrostatic pressure processing (HPP) to inactivate and kill pathogenic bacteria present in food or in raw ingredients (Toepfl et al., 2006). High pressure damages cellular membranes, resulting in leakage of cell contents; oligomeric proteins and protein complexes also undergo dissociation (Gross & Jaenicke, 1994). In combination these cellular injuries lead to cell inactivation and death. Protein and nucleic acid complexes in the cell with critical functions, e.g. ribosomes and the translation apparatus (Niven et al., 1999) and septal rings (Kawarai et al., 2004) are particularly vulnerable...

show abstract

Section: Effects Of Hpp On Translation-apparatus-related Genesmentioning

confidence: 99%

mentioning

confidence: 99%

Differential gene expression of Listeria monocytogenes during high hydrostatic pressure processing

2008

View full text Add to dashboard Cite

show abstract

“…The effects of pressure on L. lactis in dependence on temperatures, pH values and baroprotective additives are reported in detail by Molina-Höppner (2002), Kilimann et al (2004a,b) and Kilimann et al (2005). In the frame of current work, these data sets are gathered in one data set in order to carry out a kinetic modelling in the required parameter space (temperature, pressure, holding time and additive concentration).…”

Section: Resultsmentioning

confidence: 99%

“…The obtained inactivation model for L. lactis allows the prediction of nearly all types of inactivation such as the shoulder type (no inactivation), the linear with preceding shoulder type, the sigmoid type (shoulder-linear tailing), the linear with tailing type and the purely linear type (Cheftel, 1995;Lee et al, 2001;Mafart et al, 2002;Xiong et al, 1999). Furthermore, compared to a rule and data-based model (Kilimann et al, 2004a(Kilimann et al, , 2005, this equation-based model is more suitable for a coupling with HP-CFD (see below).…”

Section: Microbial Modellingmentioning

confidence: 99%

Experimental and numerical study of heterogeneous pressure‐temperature‐induced lethal and sublethal injury of Lactococcus Lactis in a medium scale high‐pressure autoclave

Kilimann

Kitsubun

Delgado

et al. 2006

Biotech & Bioengineering

View full text Add to dashboard Cite

The present contribution is dedicated to experimental and theoretical assessment of microbiological process heterogeneities of the high-pressure (HP) inactivation of Lactococcus lactis ssp. cremoris MG 1363. The inactivation kinetics are determined in dependence of pressure, process time, temperature and absence or presence of co-solutes in the buffer system namely 4 M sodium chloride and 1.5 M sucrose. The kinetic analysis is carried out in a 0.1-L autoclave in order to minimise thermal and convective effects. Upon these data, a deterministic inactivation model is formulated with the logistic equation. Its independent variables represent the counts of viable cells (viable but injured) and of the stress-resistant cells (viable and not injured). This model is then coupled to a thermo-fluiddynamical simulation method, high-pressure computer fluid dynamics technique (HP-CFD), which yields spatiotemporal temperature and flow fields occurring during the HP application inside any considered autoclave. Besides the thermo-fluiddynamic quantities, the coupled model predicts also the spatiotemporal distribution of both viable (VC) and stress-resistant cell counts (SRC). In order to assess the process non-uniformity of the microbial inactivation in a 3.3-L autoclave experimentally, microbial samples are placed at two distinct locations and are exposed to various process conditions. It can be shown with both, experimental and theoretical models that thermal heterogeneities induce process non-uniformities of more than one decimal power in the counts of the viable cells at the end of the treatment.

show abstract

“…Recent findings show that pressure affects primarily functions of the cell membrane through inactivation of membrane-bound proteins and pressure-induced phase transitions of the lipid bilayer (e.g. Kilimann, Hartmann, Delgado, Vogel, & Gänzle, 2005;Ulmer et al, 2002).…”

Section: Introductionmentioning

confidence: 99%

Mechanical stresses in cellular structures under high hydrostatic pressure

Hartmann

Mathmann

Delgado

2006

Innovative Food Science & Emerging Technologies

View full text Add to dashboard Cite

A fuzzy logic-based model for the multistage high-pressure inactivation of ssp. MG 1363

Cited by 33 publications

References 27 publications

Differential gene expression of Listeria monocytogenes during high hydrostatic pressure processing

Differential gene expression of Listeria monocytogenes during high hydrostatic pressure processing

Experimental and numerical study of heterogeneous pressure‐temperature‐induced lethal and sublethal injury of Lactococcus Lactis in a medium scale high‐pressure autoclave

Mechanical stresses in cellular structures under high hydrostatic pressure

Contact Info

Product

Resources

About