Hydrostatic pressure treatment of food: microbiology

Knorr, Dietrich

doi:10.1007/978-1-4615-2105-1_8

Cited by 117 publications

(83 citation statements)

References 39 publications

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“…it was assumed that pressure caused inactivation of spores by first initiating germination and then inactivating germinated forms. the spore germination could be induced by hydrostatic pressure of 100-300 MPa and resultant vegetative cells are sensitive to environmental conditions (33,34).…”

Section: High Pressure Processing and Microbial Inactivationmentioning

confidence: 99%

High Pressure Processing for Foods Preserving

Yordanov

Angelova

2010

Biotechnology & Biotechnological Equipment

123

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Section: High Pressure Processing and Microbial Inactivationmentioning

confidence: 99%

High Pressure Processing for Foods Preserving

Yordanov

Angelova

2010

Biotechnology & Biotechnological Equipment

123

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“…The extent of HHP microbial inactivation depends on treatment variables such as pressure, time and temperature of exposure, composition of the food, and type of micro-organisms involved (Hoover et al 1989;Cheftel 1995;Knorr 1995;Palou et al 1997). Fungal spores (conidia) are easily inactivated at pressures of 300 (Aspergillus oryzae) or 400 MPa (Rhizopus javanicus) at ambient temperatures (Cheftel 1995).…”

Section: Introductionmentioning

confidence: 99%

Effect of oscillatory high hydrostatic pressure treatments on Byssochlamys nivea ascospores suspended in fruit juice concentrates

Palou

López‐Malo

Barbosa‐Cánovas

et al. 1998

Lett Appl Microbiol

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and oscillatory (one, three or five cycles at 689 MPa with holding times of 1 s) high hydrostatic pressure treatments on the viability of Byssochlamys nivea ascospores suspended in apple and cranberry juice concentrates adjusted by dilution to water activities (a w ) of 0·98 and 0·94 was evaluated at 21 and 60°C. Inactivation of the initial spore inocula was achieved after three or five cycles of oscillatory pressurization at 60°C when the a w was 0·98 in both fruit juices. With a w 0·94, the initial inocula were reduced by less than 1 log-cycle after five pressure cycles. Inactivation was not observed within 25 min with continuous pressurization at 60°C. In treatments at 21°C, no effect on spore viability was observed with continuous or oscillatory treatments.

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“…Baroprotective effects of sodium chloride or sugars have been observed in studies with Escherichia coli, Saccharomyces cerevisiae, Zygosaccharomyces spp., and Rhodoturula rubra (14,17,24,25,36). The influence of salts or sugars on the water activity (a w ) of foods or suspension media does not explain the marked baroprotective effects of these solutes (21,29), and it has been suggested that specific interactions between sugars and biological macromolecules contribute to their baroprotective effects (11).…”

mentioning

confidence: 99%

Protective Effect of Sucrose and Sodium Chloride for Lactococcus lactis during Sublethal and Lethal High-Pressure Treatments

Molina-Höppner

Doster

Vogel

et al. 2004

Appl Environ Microbiol

172

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The bactericidal effect of hydrostatic pressure is reduced when bacteria are suspended in media with high osmolarity. To elucidate mechanisms responsible for the baroprotective effect of ionic and nonionic solutes, Lactococcus lactis was treated with pressures ranging from 200 to 600 MPa in a low-osmolarity buffer or with buffer containing 0.5 M sucrose or 4 M NaCl. Pressure-treated cells were characterized in order to determine viability, the transmembrane difference in pH (⌬pH), and multiple-drug-resistance (MDR) transport activity. Furthermore, pressure effects on the intracellular pH and the fluidity of the membrane were determined during pressure treatment. In the presence of external sucrose and NaCl, high intracellular levels of sucrose and lactose, respectively, were accumulated by L. lactis; 4 M NaCl and, to a lesser extent, 0.5 M sucrose provided protection against pressure-induced cell death. The transmembrane ⌬pH was reversibly dissipated during pressure treatment in any buffer system. Sucrose but not NaCl prevented the irreversible inactivation of enzymes involved in pH homeostasis and MDR transport activity. In the presence 0.5 M sucrose or 4 M NaCl, the fluidity of the cytoplasmic membrane was maintained even at low temperatures and high pressure. These results indicate that disaccharides protect microorganisms against pressure-induced inactivation of vital cellular components. The protective effect of ionic solutes relies on the intracellular accumulation of compatible solutes as a response to the osmotic stress. Thus, ionic solutes provide only asymmetric protection, and baroprotection with ionic solutes requires higher concentrations of the osmolytes than of disaccharides.The accumulation of compatible solutes, such as betaines, proline, and sugars, is a widespread response of microorganisms to elevated environmental osmotic pressures (41). According to a recent definition, a compatible solute is a "cytoplasmic cosolvent (solute) whose levels can be modulated over a broad range without disrupting cellular function" (24, 43). Compatible solutes contribute to the osmotic balance with the extracellular environment, enhance the stability of enzymes, and preserve the integrity of biological membranes (41). The composition of the osmolytes that are accumulated depends on the type of osmotic shock (i.e., ionic stress versus nonionic stress) and the presence of specific compatible solutes in the medium. In addition to their role as osmotic balancers, compatible solutes provide protection against high temperature, freeze-thaw treatment, and drying (41, 43).When the osmotic pressure of the medium is increased, the tolerance of microorganisms to high hydrostatic pressure is enhanced. Baroprotective effects of sodium chloride or sugars have been observed in studies with Escherichia coli, Saccharomyces cerevisiae, Zygosaccharomyces spp., and Rhodoturula rubra (14,17,24,25,36). The influence of salts or sugars on the water activity (a w ) of foods or suspension media does not explain the marked baroprotectiv...

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Hydrostatic pressure treatment of food: microbiology

Cited by 117 publications

References 39 publications

High Pressure Processing for Foods Preserving

High Pressure Processing for Foods Preserving

Effect of oscillatory high hydrostatic pressure treatments on Byssochlamys nivea ascospores suspended in fruit juice concentrates

Protective Effect of Sucrose and Sodium Chloride for Lactococcus lactis during Sublethal and Lethal High-Pressure Treatments

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