Effect of Cheese Water Activity and Carbohydrate Content on the Barotolerance of Listeria monocytogenes Scott A

2006 ◽  
Vol 69 (6) ◽  
pp. 1328-1333 ◽  
Author(s):  
PILAR MORALES ◽  
JAVIER CALZADA ◽  
BUENAVENTURA RODRÍGUEZ ◽  
MÁXIMO de PAZ ◽  
PILAR GAYA ◽  
...  
Keyword(s):  
High Pressure ◽  
Listeria Monocytogenes ◽  
Water Activity ◽  
Dry Matter ◽  
High Pressure Processing ◽  
Carbohydrate Content ◽  
Pressure Treatment ◽  
High Pressure Treatment ◽  
Log Reduction ◽  
Fresh Cheese

High-pressure processing is an appropriate technique for improving the microbiological safety of packaged ready-to-eat foods. The effect of high-pressure treatment on Listeria monocytogenes Scott A inoculated into fresh Hispánico-type cheese and ripe Mahón cheese was investigated. A 3.8-log reduction in the counts of L. monocytogenes Scott A in fresh cheese was recorded after 3 min at 400 MPa and 12°C, whereas 18 min under the same conditions was required to obtain a 1-log reduction in ripe cheese. Dry matter values were 48.96% for fresh cheese and 58.79% for ripe cheese, and water activity (aw) values were 0.983 and 0.922, respectively. In dehydrated fresh cheese (58.20% dry matter) in which 5% NaCl was added to achieve a 0.904 aw value, L. monocytogenes Scott A counts were lowered by only 0.4 log after treatment for 10 min at 400 MPa. On the other hand, in a 60:40 mixture of ripe cheese:distilled water with a 0.976 aw value, the reduction under the same conditions was 3.9 log. Within the aw range of 0.945 to 0.965, L. monocytogenes Scott A barotolerance was significantly higher in fresh cheese than in ripe cheese for equivalent aw values. Carbohydrate content was higher in fresh cheese than in ripe cheese. The addition of lactose at a concentration of 5 mg/g to an 85:15 mixture of ripe cheese:distilled water did not influence L. monocytogenes Scott A barotolerance during treatment for 10 min at 400 MPa. Galactose at a concentration of 5 mg/g had a protective effect during high-pressure treatment, and glucose at a concentration of 5 mg/g favored L. monocytogenes Scott A survival during refrigerated storage of pressurized samples at 8°C for 5 days.

scholarly journals Combined Effect of Microencapsulated Horseradish Juice and High-Pressure Treatment on Pork Quality During Storage

2021 ◽  
Vol 75 (6) ◽  
pp. 463-468
Author(s):  
Sanita Sazonova ◽  
Lolita Tomsone ◽  
Ruta Galoburda ◽  
Ilze Grāmatiņa ◽  
Thierry Talou
Keyword(s):  
High Pressure ◽  
Water Activity ◽  
Meat Products ◽  
Antimicrobial Properties ◽  
High Pressure Processing ◽  
Plate Count ◽  
Meat Sample ◽  
Pressure Treatment ◽  
Pork Meat ◽  
High Pressure Treatment

Abstract High-pressure processing (HPP) is well suited to combine consumer demand for meat products with minimal heat treatment without compromising product safety. In turn, herbs have antioxidant and antimicrobial properties. The aim of this study was to evaluate the application of hurdle technology combining microencapsulated horseradish root and leaf juice with HPP (300 MPa; 15 min) for extending of the raw pork meat shelf life. Water activity (aw), pH, colour, hardness, and micro-biological parameters of meat were evaluated during 21-day storage. Total plate count (TPC) in HPP treated samples was significantly smaller (p < 0.05) compared to untreated samples during storage until the day 14. On day 21, the TPC in processed samples was still slightly lower, however, at this point significance was not established between samples. Water activity dynamics in the HPP-treated microencapsulated pork meat samples differed significantly from other samples. Hardness decreased during storage, but no significant differences were found between samples. The L* values and pH of the meat were not significantly influenced by the added microencapsulated juice, but by high pressure treatment. Treatment with microencapsulated horseradish juice had a positive effect on the TPC and aw of the meat sample.

Effect of High Hydrostatic Pressure on Salmonella Inoculated into Creamy Peanut Butter with Modified Composition

2014 ◽  
Vol 77 (10) ◽  
pp. 1664-1668 ◽  
Author(s):  
TANYA D'SOUZA ◽  
MUKUND KARWE ◽  
DONALD W. SCHAFFNER
Keyword(s):  
High Pressure ◽  
Hydrostatic Pressure ◽  
Water Activity ◽  
High Hydrostatic Pressure ◽  
Peanut Butter ◽  
High Pressure Processing ◽  
Peanut Oil ◽  
Peanut Flour ◽  
Log Reduction ◽  
High Hydrostatic Pressure Processing

Peanut butter has been associated with several large foodborne salmonellosis outbreaks. This research investigates the potential of high hydrostatic pressure processing (HPP) for inactivation of Salmonella in peanut butter of modified composition, both by modifying its water activity as well by the addition of various amounts of nisin. A cocktail of six Salmonella strains associated with peanut butter and nut-related outbreaks was used for all experiments. Different volumes of sterile distilled water were added to peanut butter to increase water activity, and different volumes of peanut oil were added to decrease water activity. Inactivation in 12% fat, light roast, partially defatted peanut flour, and peanut oil was also quantified. Nisaplin was incorporated into peanut butter at four concentrations corresponding to 2.5, 5.0, 12.5, and 25.0 ppm of pure nisin. All samples were subjected to 600 MPa for 18 min. A steady and statistically significant increase in log reduction was seen as added moisture was increased from 50 to 90%. The color of all peanut butter samples containing added moisture contents darkened after high pressure processing. The addition of peanut oil to further lower the water activity of peanut butter further reduced the effectiveness of HPP. Just over a 1-log reduction was obtained in peanut flour, while inactivation to below detection limits (2 log CFU/g) was observed in peanut oil. Nisin alone without HPP had no effect. Recovery of Salmonella after a combined nisin and HPP treatment did show increased log reduction with longer storage times. The maximum log reduction of Salmonella achieved was 1.7 log CFU/g, which was comparable to that achieved by noncycling pressure treatment alone. High pressure processing alone or with other formulation modification, including added nisin, is not a suitable technology to manage the microbiological safety of Salmonella-contaminated peanut butter.

Inactivation of Yersinia pseudotuberculosis 197 and Francisella tularensis LVS in Beverages by High Pressure Processing

2009 ◽  
Vol 72 (1) ◽  
pp. 165-168 ◽  
Author(s):  
JOSEPH E. SCHLESSER ◽  
BRIAN PARISI
Keyword(s):  
High Pressure ◽  
Francisella Tularensis ◽  
Orange Juice ◽  
Yersinia Pseudotuberculosis ◽  
Hold Time ◽  
Skim Milk ◽  
High Pressure Processing ◽  
Pressure Treatment ◽  
Log Reduction ◽  
Pressure Resistance

In 2003, the U.S. Department of Health and Human Services announced a new research program to develop technologies and strategies to prevent and minimize potential food safety and security threats. The threat of terrorist attacks against the nation's food supplies has created the need to study microorganisms not typically associated with foodborne illness. High-pressure processing has been proposed as a treatment to reduce Yersinia pestis and Francisella tularensis LVS levels in beverages. The objectives of this work were to determine the pressure resistance of Y. pseudotuberculosis 197 (surrogate for Y. pestis) and F. tularensis LVS (vaccine strain). For each bacterium, samples of ultrahigh-temperature pasteurized skim milk and pasteurized reduced-acid orange juice (pH ca. 4.2) were inoculated at a minimum level of 5 log CFU/ml. Ten-milliliter samples of the inoculated product were vacuum sealed in polyester pouches and subjected to pressures of 300 and 500 MPa for holding times ranging from 30 s to 6 min. One set of trials was performed at an initial temperature of 10°C and another at 25°C. Processed samples were immediately plated and enumerated. A pressure treatment of 300 MPa at 25°C for less than 6 min was not sufficient to achieve a 5-log reduction of Y. pseudotuberculosis 197 or F. tularensis LVS in milk. However, a pressure treatment of 500 MPa was effective at hold times as low as 30 s. Overall, F. tularensis LVS demonstrated less pressure resistance than Y. pseudotuberculosis 197. Based on these findings, a high-pressure process designed to inactivate 5 log CFU of Y. pseudotuberculosis 197 per ml and F. tularensis LVS in orange juice or milk should be set at or above 500 MPa with a hold time of 2 min or greater.

scholarly journals Flooding Stress and High-Pressure Treatment Enhance the GABA Content of the Vegetable Soybean (Glycine max Merr.)

Agriculture ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 175 ◽  
Author(s):  
Man-Shin Shiu ◽  
Yuan-Tay Shyu ◽  
Sz-Jie Wu
Keyword(s):  
High Pressure ◽  
Glycine Max ◽  
High Pressure Processing ◽  
Acid Decarboxylase ◽  
Pressure Treatment ◽  
Vegetable Soybean ◽  
High Pressure Treatment ◽  
Flooding Stress ◽  
Semialdehyde Dehydrogenase ◽  
Gaba Content

γ-aminobutyric acid (GABA) is the chief inhibitory neurotransmitter in the central nervous system and of substantial physiological significance to mammals. The GABA content of plants is generally low; however, it increases significantly when plants encounter stress. The present study investigates the effects of flooding stress and high-pressure processing on GABA content enrichment in the vegetable soybean (Glycine max Merr.) cultivar Kaohsiung No. 9 and potential mechanisms. Results indicate that flooding stress increased the GABA content of vegetable soybean kernels, with the possible mechanism involving the upregulation of glutamic acid decarboxylase 5 (GAD5) and aminoaldehyde dehydrogenase (AMADH) and downregulation of succinate semialdehyde dehydrogenase (SSADH). High-pressure treatment increased the GABA content through increased GAD activity. A specific combination of flooding stress, high-pressure treatment, and storage treatment enhanced vegetable soybean GABA content up to 696.6 ± 65.7 mg/100 g. Flooding treatment prior to harvesting did not cause differences in consumption quality. These results show that flooding stress and high pressure treatment can increase GABA content and enhance the functional value of the vegetable soybean cultivar Kaohsiung No. 9.

Effect of High-Pressure Treatment on the Survival of Listeria monocytogenes Scott A in Sliced Vacuum-Packaged Iberian and Serrano Cured Hams

2006 ◽  
Vol 69 (10) ◽  
pp. 2539-2543 ◽  
Author(s):  
PILAR MORALES ◽  
JAVIER CALZADA ◽  
MANUEL NUÑEZ
Keyword(s):  
High Pressure ◽  
Listeria Monocytogenes ◽  
Detrimental Effect ◽  
Vacuum Packaging ◽  
Sensory Characteristics ◽  
Pressure Treatment ◽  
High Pressure Treatment ◽  
Microbiological Safety ◽  
Holding Period ◽  
And Control

High-pressure treatment is useful for increasing the microbiological safety of ready-to-eat foods. With dry-cured hams, this treatment can be applied to the finished product after slicing and vacuum packaging. The effect of high-pressure treatment on the survival of inoculated Listeria monocytogenes Scott A and on the sensory characteristics of two Spanish dry-cured hams, Iberian and Serrano, was investigated. Ham slices were inoculated with L. monocytogenes at 6 × 106 CFU/g and held at 4°C for 20 h before high-pressure treatment. During this holding period, the population of the pathogen declined by 0.44 and 0.51 log CFU/g in Iberian and Serrano hams, respectively. Treatment at 450 MPa for 10 min at 12°C reduced L. monocytogenes populations by 1.50 and 1.16 log CFU/g in Iberian and Serrano hams, respectively. During the first week of storage at4or 8°C, L. monocytogenes populations declined by an average 0.89 log CFU/g in pressurized Iberian ham and 2.09 log CFU/g in pressurized Serrano ham. After 60 days at 4 or 8°C, the respective populations in pressurized and control hams were 3.24 and 4.70 log CFU/g for Iberian ham and 2.73 and 5.07 log CFU/g for Serrano ham. The color parameters L* and a* were not influenced by high-pressure treatment, and parameter b* was increased only in Iberian ham. Sensory characteristics of hams were not affected by high-pressure treatment. Treatment of Iberian and Serrano hams at 450 MPa for 10 min significantly reduced the population of L. monocytogenes Scott A without a detrimental effect on the sensory characteristics of the hams.

Effects of High Pressure, Subzero Temperature, and pH on Survival of Listeria monocytogenes in Buffer and Smoked Salmon

2008 ◽  
Vol 71 (8) ◽  
pp. 1612-1618 ◽  
Author(s):  
M. RITZ ◽  
F. JUGIAU ◽  
M. FEDERIGHI ◽  
N. CHAPLEAU ◽  
M. de LAMBALLERIE
Keyword(s):  
High Pressure ◽  
Listeria Monocytogenes ◽  
Differential Resistance ◽  
High Pressure Processing ◽  
Food Preservation ◽  
Subzero Temperature ◽  
Freezing Process ◽  
Pressure Treatment ◽  
Bacterial Cells ◽  
Smoked Salmon

High pressure processing is a novel food preservation technology, applied for over 15 years in the food industry to inactivate spoilage and pathogenic microorganisms. Many studies have shown the differential resistance of bacterial cells to high pressure. Listeria monocytogenes is a bacterium able to grow at refrigerated temperature and to survive for a long time in minimally processed foods such as raw smoked fish. The freezing process does not cause significant decline of L. monocytogenes. The phase diagram of water under pressure permits a pressure treatment under subzero temperature, without the disadvantages of freezing for food quality. The aim of this study was to estimate if combined effects of pressure and subzero temperature could increase the destruction of L. monocytogenes in buffer and in smoked salmon. We investigated effects of high pressure processing (100, 150, and 200 MPa) combined with subzero temperatures (−10, −14, and −18°C) and pH (7.0 and 4.5). Results showed that the most effective high-pressure treatment to inactivate L. monocytogenes was 200 MPa, −18°C, and pH 4.5. The relevance of pressure holding time and the synergistic effect of pressure coupled with the subzero temperature to inactivate bacteria are highlighted. Modifications of physical properties (color and texture) were a lightening of color and an increase of toughness, which might be accepted by consumers, since safety is increased.

Pressure Death and Tailing Behavior of Listeria monocytogenes Strains Having Different Barotolerances

2003 ◽  
Vol 66 (11) ◽  
pp. 2057-2061 ◽  
Author(s):  
ABDULLATIF TAY ◽  
THOMAS H. SHELLHAMMER ◽  
AHMED E. YOUSEF ◽  
GRADY W. CHISM
Keyword(s):  
High Pressure ◽  
Listeria Monocytogenes ◽  
High Pressure Processing ◽  
Pressure Treatment ◽  
Probable Number ◽  
Potential Target ◽  
Pressure Sensitive ◽  
Wide Range ◽  
Pressure Resistance ◽  
Kinetics Of

The objectives of this study were to investigate the variability among Listeria monocytogenes strains in response to high-pressure processing, identify the most resistant strain as a potential target of pressure processing, and compare the inactivation kinetics of pressure-resistant and pressure-sensitive strains under a wide range (350 to 800 MPa) of pressure treatments. The pressure resistance of Listeria innocua and nine strains of L. monocytogenes was compared at 400 or 500 MPa and 30°C. Significant variability among strains was observed. The decrease in log CFU/ml during the pressure treatment was from 1.4 to 4.3 at 400 MPa and from 3.9 to &gt;8 at 500 MPa. L. monocytogenes OSY-8578 exhibited the greatest pressure resistance, Scott A showed the greatest pressure sensitivity, and L. innocua had intermediate resistance. On the basis of these findings, L. monocytogenes OSY-8578 is a potential target strain for high-pressure processing efficacy studies. The death kinetics of L. monocytogenes Scott A and OSY-8578 were investigated at 350 and 800 MPa. Survivors at 350 MPa were enumerated by direct plating, and survivors at 800 MPa were enumerated by the most-probable-number technique. Both pressure-resistant and pressure-sensitive strains exhibited non–first-order death behavior, and excessive pressure treatment did not eliminate the tailing phenomenon.

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