Language：Japanese   Publisher：Japanese Society for Food Science and Technology  

<p>Food processing by high hydrostatic pressure (HHP) has several characteristic aspects, including homogeneous and almost spontaneous transmission of pressure; inactivation of viruses and microbes; suppressed deterioration of nutrients, flavors, and pigments; denaturation of food biopolymers such as proteins and starch; enhanced liquid impregnation and air bubble dissolution; and shucking of bivalves and crustaceans. Among these, microbial inactivation has been intensively studied for practical applications in processing agricultural produce with minimal quality loss and reduced risk of pathogenic and/or spoilage microbes, especially bacteria. HHP treatment, as well as other intervention technologies, may inactivate bacteria lethally and sublethally. However, sublethal inactivation of bacteria has not been elucidated sufficiently. This paper reviews bacterial inactivation by HHP with a focus on bacterial injury and recovery. </p>

DOI： 10.3136/nskkk.65.154

Web of Science

CiNii Books

researchmap

Other Link： https://agriknowledge.affrc.go.jp/RN/2010921279

Language：English   Publishing type：Research paper (scientific journal)   Publisher：SOC BIOSCIENCE BIOENGINEERING JAPAN  

Escherichia coli cells were inactivated by high hydrostatic pressure (HHP) at 400-600 MPa and their recovery under various conditions was evaluated by colony counting and flow cytometer (FCM) analyses. The lag time in colony formation and an improved recovery of cells under less oxidative conditions (pyruvate addition to the medium and incubation in anaerobic conditions) were observed for HHP treated cells, which indicated that a significant portion of cells were injured and recovered during incubation after HHP treatment. The lag time for colony formation varied, which suggested a wave of resuscitation and recovered cells may multiply before other injured cells complete resuscitation. The recovery process was monitored by FCM: The FCM profile of cells stained using propidium iodide and SYTO9 indicated that while the majority of cells died just after HHP treatment, the staining pattern of possibly injured cells displayed a specific spectrum that gradually became consistent with that of the dead cell population and a living cell population simultaneously appeared. Pyruvate addition to the medium not only enhanced viability of HHP treated cells, but also reduced the lethal effect of HHP. These observations suggested that the degree of damage by HHP may differ cell-by-cell, and oxidative stress may continue after HHP treatment. Pyruvate addition to the recovery medium enhanced viability of E. coli cells inactivated by HHP treatment in tomato juice as well. (C) 2017, The Society for Biotechnology, Japan. All rights reserved.

DOI： 10.1016/j.jbiosc.2017.01.007

Web of Science

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：TAYLOR & FRANCIS LTD  

High hydrostatic pressure (HHP) affects various cellular processes. Using a sporulation-deficient Bacillus subtilis strain, we characterized the properties of vegetative cells subjected to HHP. When stationary-phase cells were exposed to 250MPa of HHP for 10min at 25 degrees C, approximately 50% of cells were viable, although they exhibited a prolonged growth lag. The HHP-injured cells autolyzed in the presence of NaCl or KCl (at concentrations100mM). Superoxide dismutase slightly protected the viability of HHP-treated cells, whereas vegetative catalases had no effect. Thus, unlike HHP-injured Escherichia coli, oxidative stress only slightly affected vegetative B. subtilis subjected to HHP.

DOI： 10.1080/09168451.2017.1292835

Web of Science

PubMed

researchmap

Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：IOP PUBLISHING LTD  

DOI： 10.1088/1742-6596/950/3/032012

Web of Science

researchmap

Language：English   Publisher：日本食品保蔵科学会 ; 1997-  

CiNii Books

researchmap

Language：Japanese  

J-GLOBAL

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：KYUSHU UNIV, FACULTY AGRICULTURAL PUBLICATIONS  

Many previous studies have focused on biofilm formation of microorganisms under steady state, however, in actual environment around food, surroundings of food frequently fluctuate. This study investigated the bacterial biofilm formation and interaction between different strains under constant and fluctuating temperature conditions.
Firstly, biofilm formation in mixed culture of Pseudomonas putida with Salmonella enterica under a constant temperature of 5 degrees C and 30 degrees C was investigated to identify the interactions between the two species. In the result, at 5 degrees C, P putida principally formed biofilm in the mixed culture with S. enterica while S. enterica could neither form biofilm nor grow well. And, an interaction between S. enterica and P putida could not be observed at 5 degrees C. In contrast, at 30 degrees C, the acceleration of biofilm formation was observed under only poor nutrient condition. It can be considered that the bacterial interaction induced by a lack of nutrient accelerated biofilm formation in the mixed culture.
Secondly, the effect of two different patterns of temperature fluctuation on biofilm formation in the mixed culture was studied by investigating the biofilm amount and bacterial count. In consequence, temperature fluctuation inhibited biofilm formation in the mixed culture of S. enterica with P putida. However, salmonella count was promoted in comparison with that at the low constant temperature of 5 degrees C. In summary, the stress due to a lack of nutrient caused the bacterial interaction between S. enterica and R putida and accelerated biafilm formation in the mixed culture while fluctuating temperature had an inhibition effect on biofilm formation. However, considering the salmonella growth through temperature fluctuation, it is important to keep temperature constant during food distribution.

Web of Science

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：KARGER  

In this study, biofilm formation of Pseudomonas panda at a constant temperature of 5 degrees C, 10 degrees C, 20 degrees C or 30 degrees C under rich and poor nutrient conditions was investigated. For all temperature conditions, R putida initially grew and formed biofilm. Subsequently, under the rich nutrient condition, the biofilm detached after it reached maturity at a high temperature, but those at a low temperature remained attached. In contrast, under the poor nutrient condition, biofilm detachment occurred regardless of the temperature condition; thus, lack of nutrients may cause biofilm detachment. Therefore, aside from cleaning blots and strict maintenance of a low temperature during the distribution of agricultural produce, attention must be paid to biofilm detachment as it can lead to an increased risk of bacterial contamination and food poisoning.

DOI： 10.3136/fstr.18.879

Web of Science

researchmap

Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：INT SOC HORTICULTURAL SCIENCE  

The bacterial adherent characteristics of two pathogens (Salmonella enterica, Staphylococcus aureus) on the surface of polystyrene were investigated under a fluctuating temperature regime and different nutrient levels (trypticase soy broth). Bacterial adhesions were evaluated by the optical density value of bacterial cells stained with 0.1% (w/v) of crystal violet solution. Under constant temperature conditions at 5 and 30 degrees C, the adherent potentials of both S. enterica and S. aureus were stable at the end of incubation (5 days). Under a fluctuating temperature regime, the cell adhesion potentials were changed with the period of incubation. The adhesions of both pathogens were considerably increased by rapid temperature elevation from 5 to 30 degrees C, while approximately twice the optical density value of cell adhesion of S. enterica was observed on the polystyrene surface compared with constant conditions. Transferring the sample tube to 5 degrees C after fluctuation from 5 to 30 degrees C led to considerable cell detachment of S. enterica by the end of incubation. It was probable that S. enterica cells used in this study was extremely sensitive to environmental variation, consequently cell adhesion and release could be observed under fluctuating temperature conditions. Meanwhile, stable adhesion of S. aureus cells was observed at 5 degrees C after temperature fluctuations from 5 to 30 degrees C.

Web of Science

researchmap

Language：Japanese  

J-GLOBAL

researchmap

Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：INT SOC HORTICULTURAL SCIENCE  

The adherent characteristics of bacteria isolated from cabbage and cucumber fruits on the inner surface of a polystyrene test tube were investigated under fluctuating temperature conditions. Fluctuation cycles set at 5 degrees C for 24h and 30 degrees C for 24h were repeated until the fifth day. Two levels of nutrient (trypticase soy broth: fresh broth and 5% of fresh broth) conditions were prepared. Bacterial adhesions were evaluated by the OD500 value of bacterial cells stained with 0.1% (w/v) of crystal violet solution. The adhesions of the isolated bacterial group of cucumber fruits gradually increased with incubating days under fluctuating temperature. Approximately two times of OD500 value was observed in the 5% of trypticase soy broth condition compared with that in rich nutrition. The rate of bacterial adhesion under poor nutrient condition for 5 days was almost the same as that observed under steady temperature conditions of 15 and 30 degrees C. Remarkable bacterial adhesions were observed under fluctuating temperature conditions for three days. However, the gradual increases in the OD500 value were obtained under steady temperature conditions for 5 days incubation in case of isolates from cabbage. The adherent potentials of many kinds of bacteria isolated from fresh produces might be stimulated by the temperature fluctuation during incubation. These results indicated that exposure of produce to high temperature during the distribution chain could influence the bacterial adhesions, and lead to biofilm formations on the surface of fresh produces.

Web of Science

researchmap

Language：Japanese   Publisher：公益社団法人 日本食品科学工学会  

&lt;p&gt;Food processing by high hydrostatic pressure (HHP) has several characteristic aspects, including homogeneous and almost spontaneous transmission of pressure; inactivation of viruses and microbes; suppressed deterioration of nutrients, flavors, and pigments; denaturation of food biopolymers such as proteins and starch; enhanced liquid impregnation and air bubble dissolution; and shucking of bivalves and crustaceans. Among these, microbial inactivation has been intensively studied for practical applications in processing agricultural produce with minimal quality loss and reduced risk of pathogenic and/or spoilage microbes, especially bacteria. HHP treatment, as well as other intervention technologies, may inactivate bacteria lethally and sublethally. However, sublethal inactivation of bacteria has not been elucidated sufficiently. This paper reviews bacterial inactivation by HHP with a focus on bacterial injury and recovery. &lt;/p&gt;

researchmap

Language：Japanese   Publisher：愛媛大学農学部  

researchmap

Language：Japanese  

J-GLOBAL

researchmap

Language：Japanese  

J-GLOBAL

researchmap

Language：Japanese  

CiNii Books

J-GLOBAL

researchmap

researchmap

researchmap

Language：Japanese  

J-GLOBAL

researchmap

Language：Japanese  

J-GLOBAL

researchmap

Language：Japanese  

J-GLOBAL

researchmap

Language：Japanese  

J-GLOBAL

researchmap

Language：Japanese  

J-GLOBAL

researchmap

researchmap

researchmap

Language：Japanese  

J-GLOBAL

researchmap

Language：Japanese  

J-GLOBAL

researchmap

Language：Japanese   Publisher：缶詰技術研究会  

CiNii Books

J-GLOBAL

researchmap

Language：Japanese  

J-GLOBAL

researchmap

Language：Japanese  

CiNii Books

J-GLOBAL

researchmap

Language：Japanese  

J-GLOBAL

researchmap

Language：Japanese  

J-GLOBAL

researchmap

Language：Japanese  

J-GLOBAL

researchmap

Language：Japanese  

J-GLOBAL

researchmap

J-GLOBAL

researchmap

Language：Japanese  

researchmap

Language：Japanese  

researchmap

Language：Japanese  

researchmap

Language：Japanese  

researchmap

Language：Japanese  

researchmap

Language：Japanese  

researchmap

Language：Japanese  

researchmap

Language：Japanese  

researchmap

Language：Japanese  

researchmap

Language：Japanese  

researchmap

Language：Japanese  

researchmap

Language：Japanese  

researchmap

Language：Japanese  

researchmap

Language：Japanese  

researchmap

Language：Japanese  

researchmap

Language：Japanese  

researchmap

Language：Japanese  

researchmap

Language：Japanese  

researchmap

Language：Japanese  

researchmap

Language：Japanese  

researchmap

Language：Japanese  

researchmap

Language：Japanese  

researchmap

Language：Japanese  

researchmap

Language：Japanese  

researchmap

Language：Japanese  

researchmap

Language：Japanese  

researchmap

Language：Japanese  

researchmap

Language：Japanese  

researchmap

Language：Japanese  

researchmap

Language：Japanese  

researchmap

Language：Japanese  

researchmap

Language：Japanese  

researchmap

Language：Japanese  

researchmap

Language：Japanese  

researchmap

Language：Japanese  

researchmap

Language：Japanese  

researchmap

Language：Japanese  

researchmap

Language：Japanese  

researchmap

Language：Japanese  

researchmap