Time filter

Source Type

Sokolowska B.,Prof Waclaw Dabrowski Institute Of Agriculture And Food Biotechnology | Skapska S.,Prof Waclaw Dabrowski Institute Of Agriculture And Food Biotechnology | Fonberg-Broczek M.,Polish Academy of Sciences | Niezgoda J.,Prof Waclaw Dabrowski Institute Of Agriculture And Food Biotechnology | And 3 more authors.
Polish Journal of Microbiology | Year: 2015

Given the importance of spoilage caused by Alicyclobacillus acidoterrestris for the fruit juice industry, the objective of this work was to study the germination and inactivation of A. acidoterrestris spores induced by moderate hydrostatic pressure. Hydrostatic pressure treatment can induce the germination and inactivation of A. acidoterrestris spores. At low pH, spore germination of up to 3.59-3.75 log and inactivation of 1.85-2.04 log was observed in a low pressure window (200-300 MPa) applied at 50 °C for 20 min. Neutral pH suppressed inactivation, the number of spores inactivated at pH 7.0 was only 0.24-1.06 log. The pressurization temperature significantly affected spore germination and inactivation. The degree of germination in apple juice after pressurization for 30 min with 200 MPa at 20 °C was 2.04 log, with only 0.61 log of spores being inactivated, while at 70 °C spore germination was 5.94 log and inactivation 4.72 log. This temperature strongly stimulated germination and inactivation under higher (500 MPa) than lower (200 MPa) pressure. When the oscillatory mode was used, the degree of germination and inactivation was slightly higher than at continuous mode. The degree of germination and inactivation was inversely proportional to the soluble solids content and was lowest in concentrated apple juice.


Porebska I.,Prof Waclaw Dabrowski Institute Of Agriculture And Food Biotechnology | Rutkowska M.,Polish Academy of Sciences | Sokolowska B.,Prof Waclaw Dabrowski Institute Of Agriculture And Food Biotechnology
High Pressure Research | Year: 2015

Alicyclobacillus acidoterrestris is a spore-forming bacterium, causing spoilage of juices. The spores of these bacteria have the ability to survive in the typical conditions used for thermal pasteurization. Therefore, the use of other techniques such as high hydrostatic pressure is considered for their inactivation. The effect of hydrostatic pressure of 200-500 MPa, at temperatures 4-50°C for 15 min, on the dynamics of germination of A. acidoterrestris spores in apple juice and pH 4 buffer was studied. To estimate the share of germinated spores, the method of determining the optical density at a wavelength of 660 nm (OD660) was used. Parameters of hydrostatic pressure treatment used in this work affected the dynamics of germination of A. acidoterrestris spores in apple juice, and the temperature had the greatest effect. The results indicate that nutrients present in apple juice can promote the germination of A. acidoterrestris spores. © 2015 Taylor and Francis.


Sokolowska B.,Prof Waclaw Dabrowski Institute Of Agriculture And Food Biotechnology | Skapska S.,Prof Waclaw Dabrowski Institute Of Agriculture And Food Biotechnology | Niezgoda J.,Prof Waclaw Dabrowski Institute Of Agriculture And Food Biotechnology | Rutkowska M.,Polish Academy of Sciences | And 2 more authors.
High Pressure Research | Year: 2014

Cells exposed to different physical and chemical treatments, including high hydrostatic pressure (HHP), suffer from injuries that could be reversible in food materials when stored. Escherichia coli and Listeria innocua cells suspended in phosphate-buffered saline (PBS) (model suspensions), and acidified beetroot juice were subjected to a pressure of 400 MPa at a temperature of 20°C for up to 10 min. The difference between the viable and non-injured cells was used to estimate the number of injured survivors.The reduction in E. coli cell number was 3.4-4.1 log after 10 min pressurization in model suspensions and 6.2 log in beetroot juice. Sublethally injured cells in PBS accounted for up to 2.7 log after 10 min HHP treatment and 0.8 log in beetroot juice. The reduction in L. innocua cell number after 10 min pressure treatment reached from 3.8 to 4.8 log, depending on the initial concentration in model suspensions. Among the surviving L. innocua cells, even up to 100% were injured. L. innocua cells were completely inactivated after 1 min HHP treatment in beetroot juice. © 2014 © 2014 Taylor & Francis.


Sokolowska B.,Prof Waclaw Dabrowski Institute Of Agriculture And Food Biotechnology | Skapska S.,Prof Waclaw Dabrowski Institute Of Agriculture And Food Biotechnology | Fonberg-Broczek M.,Polish Academy of Sciences | Niezgoda J.,Prof Waclaw Dabrowski Institute Of Agriculture And Food Biotechnology | And 3 more authors.
High Pressure Research | Year: 2013

Alicyclobacillus acidoterrestris, a thermoacidophilic and spore-forming bacterium, survives the typical pasteurization process and can cause the spoilage of juices, producing compounds associated with disinfectant-like odour (guaiacol, 2,6 - dibromophenol, 2,6 - dichlorophenol). Therefore, the use of other more effective techniques such as high hydrostatic pressure (HHP) is considered for preserving juices. The aim of this study was to search for factors affecting the resistance of A. acidoterrestris spores to HHP. The baroprotective effect of increased solute concentration in apple juice on A. acidoterrestris spores during high pressure processing was observed. During the 45 min pressurization (200 MPa, 50°C) of the spores in concentrated apple juice (71.1°Bx), no significant changes were observed in their number. However, in the juices with a soluble solids content of 35.7, 23.6 and 11.2°Bx, the reduction in spores was 1.3-2.4 log, 2.6-3.3 log and 2.8-4.0 log, respectively. No clear effect of age of spores on the survival under high pressure conditions was found. Spores surviving pressurization and subjected to subsequent HHP treatment showed increased resistance to pressure, by even as much as 2.0 log. © 2013 Copyright Taylor and Francis Group, LLC.

Loading Prof Waclaw Dabrowski Institute Of Agriculture And Food Biotechnology collaborators
Loading Prof Waclaw Dabrowski Institute Of Agriculture And Food Biotechnology collaborators