Oyster Preservation by High-Pressure Treatment

The purpose of this study was to analyze the effect of 10-min continuous pressure and pulsed pressure in two 5-min steps (400 MPa at 7°C) on the microbial flora, total volatile bases, pH, and texture of purified and unpurified oysters. High-pressure treatment reduced the number of all the target microorganisms (total viable count, H2S-producing microorganisms, lactic acid bacteria, Brochothrix thermosphacta, and coliforms), in some cases by around 5-log units. The difference between the counts in the control and the pressurized oysters remained stable throughout 41 days of storage at 2°C. No Salmonella spp. were detected in either the control batch or the pressurized batches during this storage period. Deterioration of the oyster was accompanied by increased total volatile bases, mainly in the nonpressurized samples. The pH was practically constant in the pressurized oysters and fell slightly in unpressurized samples. As for mechanical properties, shear strength values were higher in pressurized than in unpressurized oysters. Step-pulse pressurizing (400 MPa at 7°C in two 5-min pulses) produced no apparent advantages over continuous pressurizing based on any of the indices used.

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Changes in selected vitamins, microorganism counts, and sensory quality during storage of pressurised sprouted seed of alfalfa (Medicago sativa L.)

Czech Journal of Food Sciences ◽

10.17221/3398-cjfs ◽

2011 ◽

Vol 23 (No. 6) ◽

pp. 246-250 ◽

Cited By ~ 9

Author(s):

GabrovskáD ◽

I. Paulíčková ◽

E. Mašková ◽

V. Fiedlerová ◽

K. Kocurová ◽

...

Keyword(s):

High Pressure ◽

Vitamin C ◽

Sensory Quality ◽

Pantothenic Acid ◽

Storage Period ◽

Pressure Treatment ◽

High Pressure Treatment ◽

Microbiological Safety ◽

Alfalfa Seed

The aim of this study was to examine the changes of nutritional and sensory quality of sprouted alfalfa seed treated by high pressure, that take place during storage. Along with this, microbiological safety was also observed. Sprouted alfalfa seed in citric acid pickle, packed in transparent laminated bags PA/PE 80, was treated with 500 MPa high pressure for 10 minutes. The processed seed in bags was stored in a refrigerator for 21 days. The bags were sampled in regular intervals to perform analyses. The changes in the contents of vitamin C, riboflavin, niacin, and pantothenic acid were observed during storage. The same samples were also checked for microbiological safety and sensory quality. Vitamin C showed a significant decrease during storage. The content of vitamin C fell markedly after high pressure treatment (by 77%) and further decreased by 10–20% during storage. The values of riboflavin content did not change very much as a consequence of pressurisation or the storage period. The contents of niacin and pantothenic acid kept decreasing until the 3<sup>rd</sup> day of storage by some 60% in total and then remained unchanged. Sensory descriptors indicated quality decrease. High pressure treatment damaged the tissues of sprouted alfalfa seed which subsequently manifested itself particularly in the deterioration of appearance and texture quality. An additional overall impairment of the seed appearance and texture occurred during its storage. Microbiological safety of sprouted alfalfa seed was preserved throughout the storage time.  

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Effect of Low-Temperature, High-Pressure Treatment on the Survival of Escherichia coli O157:H7 and Salmonella in Unpasteurized Fruit Juices

Journal of Food Protection ◽

10.4315/0362-028x-64.8.1122 ◽

2001 ◽

Vol 64 (8) ◽

pp. 1122-1127 ◽

Cited By ~ 48

Author(s):

ALEX YEOW-LIM TEO ◽

SADHANA RAVISHANKAR ◽

CHARLES E. SIZER

Keyword(s):

Escherichia Coli ◽

High Pressure ◽

Low Temperature ◽

Apple Juice ◽

Fruit Juices ◽

Escherichia Coli O157 ◽

Pressure Treatment ◽

Salmonella Spp ◽

High Pressure Treatment ◽

E Coli

The destructive effect of high pressure (615 MPa) combined with low temperature (15°C) on various strains of Escherichia coli O157:H7 and various serovars of Salmonella in grapefruit, orange, apple, and carrot juices was investigated. The three-strain cocktail of E. coli O157:H7 (SEA13B88, ATCC 43895, and 932) was found to be most sensitive in grapefruit juice (8.34-log reduction) and least in apple juice (0.41-log reductions) when pressurized at 615 MPa for 2 min at 15°C. Correspondingly, no injured survivor was detected in grapefruit and carrot juices under similar treatment conditions. No Salmonella spp. were detected in a 2-min pressure treatment (615 MPa, 15°C) of grapefruit and orange fruit juices. Except for Enteritidis, all four serovars tested in the present study have viability loss of between 3.92- and 5.07-log reductions when pressurized in apple juice at 615 MPa for 2 min at 15°C. No injured cells were recovered from grapefruit and orange juices, whereas the same treatment demonstrated reduction in numbers of Salmonella serovars Agona and Muenchen in apple juices and to a lesser extent with Typhimurium, Agona, and Muenchen in carrot juice. The present study demonstrated that low-temperature, high-pressure treatment has the potential to inactivate E. coli O157:H7 strains and different Salmonella spp. in different fruit juices.

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Effect of high pressure treatment on properties of acid coagulated milk gel during manufacturing ofchhana– an Indian soft cottage cheese

Food Manufacturing Efficiency ◽

10.1616/1750-2683.0041 ◽

2009 ◽

Vol 2 (3) ◽

pp. 21-30

Author(s):

Jatindra K. Sahu

Keyword(s):

High Pressure ◽

Cottage Cheese ◽

Pressure Treatment ◽

High Pressure Treatment

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Comparison of Ricotta cheese made by high pressure treatment with that produced by heat treatment of sweet whey

Sciences des Aliments ◽

10.3166/sda.22.601-615 ◽

2002 ◽

Vol 22 (5) ◽

pp. 601-615 ◽

Cited By ~ 5

Author(s):

Souhail Besbes ◽

Christophe Blecker ◽

Hamadi Attia ◽

Carine Massaux ◽

Claude Deroanne

Keyword(s):

Heat Treatment ◽

High Pressure ◽

Pressure Treatment ◽

High Pressure Treatment ◽

Sweet Whey

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Effect of food processing on the antioxidant activity of flavones from Polygonatum odoratum (Mill.) Druce

Open Life Sciences ◽

10.1515/biol-2021-0010 ◽

2021 ◽

Vol 16 (1) ◽

pp. 92-101

Author(s):

Guanghui Xia ◽

Xinhua Li ◽

Zhen Zhang ◽

Yuhang Jiang

Keyword(s):

Antioxidant Activity ◽

High Pressure ◽

Food Processing ◽

Yeast Fermentation ◽

Pressure Treatment ◽

Processing Methods ◽

High Pressure Treatment ◽

Effect Of Food ◽

The Stability

Abstract Polygonatum odoratum (Mill.) Druce (POD) is a natural plant widely used for food and medicine, thanks to its rich content of a strong antioxidant agent called homoisoflavones. However, food processing methods could affect the stability of POD flavones, resulting in changes to their antioxidant activity. This study attempts to evaluate the antioxidant activity of POD flavones subject to different processing methods and determines which method could preserve the antioxidant activity of POD flavones. Therefore, flavones were extracted from POD samples, which had been treated separately with one of the four processing methods: extrusion, baking, high-pressure treatment, and yeast fermentation. After that, the antioxidant activity of the flavones was subject to in vivo tests in zebrafish embryos. The results show that yeast fermentation had the least disruption to the antioxidant activity of POD flavones, making it the most suitable food processing method for POD. By contrast, extrusion and high-pressure treatment both slightly weakened the antioxidant activity of the flavones and should be avoided in food processing. The research results provide a reference for the development and utilization of POD and the protection of its biological activity.

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