Use Of High Pressure Processing Research Articles

Recent Advances in Food Processing Using High Hydrostatic Pressure Technology

High hydrostatic pressure is an emerging non-thermal technology that can achieve the same standards of food safety as those of heat pasteurization and meet consumer requirements for fresher tasting, minimally processed foods. Applying high-pressure processing can inactivate pathogenic and spoilage microorganisms and enzymes, as well as modify structures with little or no effects on the nutritional and sensory quality of foods. The U.S. Food and Drug Administration (FDA) and the U.S. Department of Agriculture (USDA) have approved the use of high-pressure processing (HPP), which is a reliable technological alternative to conventional heat pasteurization in food-processing procedures. This paper presents the current applications of HPP in processing fruits, vegetables, meats, seafood, dairy, and egg products; such applications include the combination of pressure and biopreservation to generate specific characteristics in certain products. In addition, this paper describes recent findings on the microbiological, chemical, and molecular aspects of HPP technology used in commercial and research applications.

Comparison of pressure inactivation of caliciviruses and picornaviruses in a model food system

Human enteric viruses are a major cause of foodborne illnesses. The objective of this study was to determine the high pressure processing parameters necessary to inactivate hepatitis A virus (HAV), Aichi virus (AiV), and the human norovirus surrogates, feline calicivirus (FCV) and murine norovirus (MNV) in fresh salsa. Samples were treated at 250, 400 and 500 MPa for 1, 5, and 10 min at 9 °C. AiV was additionally HPP-treated at temperatures of 50, 60, 70, and 80 °C. In salsa, HAV and FCV were inactivated beyond the limit of detection after 1 min at 400 and 250 MPa, respectively. MNV was more pressure resistant than FCV, whereby 400 MPa for 1 min was needed to achieve the same degree of inactivation. AiV titers were not reduced after a 500 MPa treatment. When heat was combined with high pressure unique pressure-assisted heat stabilization was observed associated with AiV only. The manuscript Comparison of Pressure Inactivation of Caliciviruses and Picornaviruses in a Model Food System is focused on the nonthermal processing technology high pressure processing (HPP), which is a highly used technology and one that is readily accepted by consumers. This manuscript discusses the use of HPP for the inactivation of foodborne viruses from two different families on a fresh produce item that may be widely contaminated during preharvest or post-harvest. Viruses are difficult to detect and therefore technologies that can be used to inactivate them without organoleptic changes to the product are advantageous. This manuscript includes consumer acceptance of the treated product. This manuscript will be useful to industry to show the continued important of HPP in ready-to-eat food products, like salsa.

Effects of High Pressure Processing on the Quality of Vacuum Packed Fish Patties

The objective of this study was to evaluate the use of high pressure processing (HPP) as a preservation method of meat products. Vacuum-packaged fish patties were subjected to HPP (300 MPa for 30 min 15°C or 500 Mpa for 10 min at 15°C). Untreated samples represented the control group. The three groups were stored at 4°C for 0–5 weeks. Color parameters, pH, thiobarbituric (TBARS), bacterial growth, and Oxidation-Reduction Potential (ORP) were determined. The results revealed that the 500-MPa treatment inhibited bacterial growth and extended the shelf-life of fish patties to four weeks with insignificant effects on the physicochemical attributes.

High pressure control of protein structure and functionality

Purpose – This article aims to consider the use of high pressure processing in order to gain functional advantages through proteins structure control. High pressure processing has been used to produce high-quality food with extended shelf life and could also be used to modify foods functionality. Design/methodology/approach – The effect of high pressure on protein structure and functionality is looked at and comparisons are made with heat effect in places. β-lactoglobulin and whey proteins are mainly taken as examples. Findings – A controlled partial protein unfolding through mild high pressure processing could lead to a range of intermediate molecular structures. These are distinct from the native and completely unfolded structure and have been referred to as molten globules. The partly unfolded molecular states, hence, are postulated to have increased functionality and could be interesting for the food industry. Originality/value – The opportunity and challenges represented by these theoretical elements are discussed. In particular, the effect of protein concentration and aggregation is emphasised.

Combined use of high pressure and salt or sodium nitrite to control the growth of endogenous microflora in raw pork meat

Abstract The interaction of high pressure (up to 500 MPa at 20 °C for 6 min) with sodium chloride (0%–3%) or sodium nitrite (0 mg/kg–100 mg/kg) on the outgrowth of four endogenous flora of pork meat was investigated during storage after a cold-chain break. First, the effect of high pressure was investigated. Next, high-pressure treatments at 350 MPa were combined with the addition of salt or sodium nitrite. Interesting results were observed for the lactic acid bacteria of the salted samples. Whereas salt or 350 MPa processing alone was not sufficient to delay the growth of these bacteria until the end of storage, the combination treatment resulted in low microbial counts (below 2 log CFU/g) at the end of storage. The results of this study suggest the existence of a synergy between salt and high pressure that could result from pressure sensitization of bacterial cells. Industrial Relevance Meat products must contain enough hurdles to inhibit the growth of pathogenic or spoilage microorganisms. The existence of synergy between high pressure and salt or nitrite is promising for the manufacture of meat products. In fact, the use of high-pressure processing could be an approach to limit the addition of salt and nitrite while ensuring extended shelf life, as consumers demand simpler and healthier formulations.

Effect of High-Pressure Post-Packaging Pasteurization on Microbiological Quality of Ready-to-Use Vegetables

This study was designed to estimate the potential use of high-pressure processing as a post-lethality treatment for inactivating Listeria monocytogenes, Staphyloccoccus aureus and Salmonella Typhimurium in vacuum-packed ready-to-use vegetables. The ready-to-use vegetable samples were subjected to 500 MPa for 0, 5, 10, 20 and 30 min. The numbers of L. monocytogenes and S. aureus in bean sprout and spinach treated at 500 MPa still remained at the detectable level of 1.3 log cfu/g. The numbers of S. Typhimurium in balloon flower root, bean sprout, bracken, carrot, cucumber, radish, mushroom and spinach were reduced to below the detection limit after a 10-min pressure holding time. The Weibull model provided a better fit at all survival curves (n < 1) of L. monocytogenes, S. aureus and S. Typhimurium. Therefore, the results provide practical information on using high-pressure processing as an effective post-packaging intervention technology for ensuring microbiological safety of ready-to-use vegetables. Practical Applications High pressure effectively decreased the numbers of Listeria monocytogenes, Staphyloccoccus aureus and Salmonella Typhimurium inoculated in ready-to-use vegetables during the pressure come-up time and holding time. Therefore, high-pressure processing can be used as a post-packaging pasteurization treatment for inactivating foodborne pathogen contaminated in ready-to-use vegetables.

HIGH-PRESSURE DESTRUCTION KINETICS OF SPOILAGE AND PATHOGENIC MICROORGANISMS IN MANGO JUICE

ABSTRACT High-pressure (HP) destruction kinetics of three common spoilage microorganisms, Zygosaccharomyces bailii, Pichia membranaefaciens and Leuconostoc mesenteroides, and two pathogenic microorganisms, Escherichia coli O157:H7 and Listeria monocytogenes Scott A, were evaluated in processed mango juice at pressures ranging between 250 and 550 MPa and a hold time 0–60 min at 20–25C with genera-specific initial counts in the 106 to 108 cfu/mL range. Microbial destruction was evaluated based on (1) an initial kill which is due to a pressure pulse (pulse effect) and (2) a subsequent semi-logarithmic destruction during the pressure hold time. The decimal reduction times were genera-specific and decreased with an increase in pressure. Pressure sensitivity of microbial destruction rate was evaluated by a zP value. L. mesenteroides was found to be most resistant spoilage bacteria; yet its complete destruction was achieved by a 5-min treatment at 400 MPa. Pathogenic E. coli was the most resistant of all the bacterial strains tested. A six-log reduction in E. coli O157:H7 was observed at 400 MPa when treated for 10 min, while at 500 and 550 MPa, there were no survivors after the 1-min treatment. HP processes were established using a 6, 8 and 10D treatment based on E. coli O157:H7, and counts were monitored after treatment and during subsequent storage at 20, 12 and 4C for 28 days. Results showed that these processes were satisfactory because no growth of E. coli O157:H7 was observed during the entire storage time. PRACTICAL APPLICATIONS High-pressure (HP) processing is becoming a full commercial reality, and fruit-based HP processed products are appearing in the marketplace at a rapidly increasing pace. Successful use of HP processing relies on established processes based on scientifically evaluated destruction kinetics of spoilage and pathogenic microorganisms, and adequately verified process safety through microbial challenge studies. This study is based on such an approach for HP processing of mango juice demonstrating the technology to be feasible if the process is properly established. The study provides the scientific kinetic base line data for establishing HP process of mango juice, which is a well-recognized globally important exotic fruit crop.

Novel listerial genetic loci conferring enhanced barotolerance in Escherichia coli

To identify Listeria monocytogenes genes with a role in high-pressure (HP) resistance. A L. monocytogenes genomic library constructed in an Escherichia coli background was screened for loci conferring increased HP resistance. Pressure treatments at 400 megapascals for 5 min in Luria-Bertani (LB) agar were used to screen for increased resistance to pressure. Colonies arising on the treated agar plates were isolated, the plasmid extracted and the inserts sequenced to identify the genetic loci conferring HP resistance. Seven different genetic regions were identified, which encoded proteins similar to an inorganic polyphosphate/ATP-NAD kinase, the septation ring formation regulator EzrA, flagellar motor proteins MotA and MotB, proteins similar to the quorum sensing Agr system from Staphylococcus (AgrA, AgrC and AgrD), proteins similar to a transcription regulator (RpiR family) and a fructose phosphotransferase system, proteins of unknown function, and a Fur regulator. Of the seven loci confirmed, three (EzrA, MotA/B and the Agr system) maintained significantly reproducible HP tolerance when expressed in a different E. coli background. Novel genetic loci from the L. monocytogenes genome confer increased HP resistance when heterologously expressed in an E. coli background. Molecular and functional approaches to the screening of genetic elements linked to HP resistance provide greater insights into microbial inactivation and/or survival mechanisms when using HP as a means of controlling/eliminating bacterial growth. This information will ultimately have significant implications for the use of HP processing in the food industry, in terms of both food quality and safety.

Modeling time to inactivation of Listeria monocytogenes in response to high pressure, sodium chloride, and sodium lactate.

A mathematical model was developed to predict time to inactivation (TTI) by high pressure processing of Listeria monocytogenes in a broth system (pH 6.3) as a function of pressure (450 to 700 MPa), inoculum level (2 to 6 log CFU/ml), sodium chloride (1 or 2%), and sodium lactate (0 or 2.5%) from a 4°C initial temperature. Ten L. monocytogenes isolates from various sources, including processed meats, were evaluated for pressure resistance. The five most resistant strains were used as a cocktail to determine TTI and for model validation. Complete inactivation of L. monocytogenes in all treatments was demonstrated with an enrichment method. The TTI increased with increasing inoculum level and decreasing pressure magnitude, from 1.5 min at 700 MPa and 2 log CFU/ml, to 15 min at 450 MPa and 6 log CFU/ml. Neither NaCl nor sodium lactate significantly influenced TTI. The model was validated with ready-to-eat, uncured, Australian retail poultry products, and with product specially made at a U.S. Department of Agriculture, Food Safety and Inspection Service (FSIS)-inspected pilot plant in the United States. Data from the 210 individual product samples used for validation indicate that the model gives "fail-safe" predictions (58% with response as expected, 39% with no survivors where survivors expected, and only 3% with survivors where none were expected). This model can help manufacturers of refrigerated ready-to-eat meats establish effective processing criteria for the use of high pressure processing as a postlethality treatment for L. monocytogenes in accordance with FSIS regulations.

Minimal Effects of High‐Pressure Treatment on Salmonella enterica Serovar Typhimurium Inoculated into Peanut Butter and Peanut Products

About 1.2 billion pounds of peanut butter are consumed annually in the United States. In 2008 to 2009, an outbreak involving Salmonella Typhimurium in peanut butter led to a recall of over 3900 products by over 200 companies. More than 700 people became sick, 100 were hospitalized, and 9 people died from this outbreak. This study examines the efficacy of high-pressure processing (HPP) to decrease S. Typhimurium American Type Culture Collection (ATCC) 53647 inoculated into peanut butter and model systems. The viability of S. Typhimurium in peanut butter stored at room temperature was investigated. A culture of S. Typhimurium (6.88 log CFU/g) was inoculated into peanut butter. Following 28 d at 20 °C there was a 1.23-log reduction. Approximately 10(6) to 10(7) CFU/g S. Typhimurium were inoculated into 4 brands of peanut butter, 3 natural peanut butters and peanut flour slurries at 2, 5, and 10% peanut flour protein in peanut oil and in distilled water. All were treated at 600 MPa for 5 min at 45 °C. While significant differences were found between natural peanut butter and peanut protein mixtures, the reduction was <1.0 log. The peanut flour/oil mixtures had a 1.7, 1.6, and 1.0-log reduction from HPP (2, 5, and 10% protein, respectively) whereas peanut flour/water mixtures had a 6.7-log reduction for all protein levels. Oil had a protective effect indicating HPP may not help the microbial safety of water-in-oil food emulsions including peanut butter. Practical Application: There have been multiple outbreaks of foodborne illness involving peanut butter products. This study looks at the potential use of high-pressure processing to reduce the bacteria that may be in peanut butter.

High Pressure Processing of Meat, Meat Products and Seafood

High pressure processing (HPP) allows the decontamination of foods with minimal impact on their nutritional and sensory features. The use of HPP to reduce microbial loads has shown great potential in the meat, poultry and seafood industry. HPP has proven to be a promising technology, and industrial HPP applications have grown rapidly, especially in the stabilization of ready-to-eat meats and cured products, satisfying the demands of regulatory agencies such as the United States Department of Agriculture-Food Safety and Inspection Services (USDA-FSIS). HPP has been investigated for a wide range of operations including non-thermal decontamination of acid foods, combined pressure–heating treatments to inactivate pathogenic bacteria, pressure-supported freezing and -thawing, texturization and the removal of meat from shellfish and crustaceans. Research has also been conducted on the impact of the technology on quality features. Processing-dependent changes in muscle foods include changes in colour, texture and water-holding capacity, with endogenous enzymes playing a major role in the phenomena. This review summarizes the current approaches to the use of high hydrostatic pressure processing, focusing mainly on meat, meat products and seafood. Recent findings on the microbiological, chemical and molecular aspects of HPP technology, along with commercial and research applications, are also described.

Use of high pressure to reduce cook loss and improve texture of low-salt beef sausage batters

Abstract Methods were investigated to reduce the salt content of beef-containing smallgoods as high-salt intake has been identified as a public health risk for most individuals. Raw meat batters were manufactured from retail beef mince (4–7% fat) using various NaCl concentrations (0–2%), and were packed into casings and subjected to high pressure processing (up to 400 MPa for 2 min at 10 °C). Following pressure treatment, samples were cooked to an internal temperature of 72 °C and cooled. Cooked products were assessed for cooking loss, colour and physical consistency by texture profile analysis. Flavour and overall acceptability were assessed by sensory panels. High pressure processing (HPP) was found to produce a dramatic improvement in the moisture retention of the cooked products. Control (unpressurised) sausages containing 2% NaCl had a similar cook loss (9.3%) to pressure-treated sausages containing just 1% NaCl, whereas unpressurised samples with 1% NaCl had a cook loss of 24.9%. The hardness and gumminess of pressure-treated samples was higher compared to untreated samples, at all salt concentrations. The greatest differences in texture with pressure treatment were seen in the 1% NaCl samples. Pressure treatment generally caused no changes in the colour of either the raw or cooked product; however there was a slight increase in “whiteness” with pressure treatment. Sensory panels reported a greater acceptability in both appearance and texture of pressure-treated sausages of lower salt content compared with non-pressure-treated samples. Examination of extracted proteins using SDS-PAGE and of muscle proteins by thermal analysis indicated that pressure contributed to enhanced binding through protein solubilisation and gelation through partial protein unfolding. The application of high pressure to beef sausages with low-salt content resulted in reduced cooking losses and improved texture. Industrial relevance Enhanced meat binding through extraction of salt-soluble proteins is an essential step in the formulation of meat products such as sausages and emulsion-type products. The ability to reduce salt and achieve high binding and water retention through use of HPP is important in being able to produce healthier foods.

Consumer perception of the use of high-pressure processing and pulsed electric field technologies in food production

The success of new food processing technologies is highly dependent on consumers’ acceptance. The purpose of this paper is to study consumers’ perceptions of two new processing technologies and food products produced by means of these novel technologies. To accomplish this, a qualitative study on consumer attitudes towards high-pressure processing (HPP) and pulsed electric field (PEF) processing of food was carried out. In all 97 adults between 20 and 71 years of age participated in 12 focus groups conducted in Slovenia, Hungary, Serbia, Slovakia, Norway and Denmark using a common guideline. Participants were introduced to the HPP and PEF technologies and then to the effect of the two new technologies on two specific product categories: juice and baby food. The transcribed data was content analysed and the coded data was transformed into diagrams using UCINET 5 and NETDRAW. The results show that consumers perceived the main advantages of HPP and PEF products to be the products’ naturalness, improved taste and their high nutritional value, whereas the main disadvantage was the lack of information about the PEF and HPP products. The results of the participants’ evaluation of the PEF and HPP processes showed that environmental friendliness and the more natural products were seen as the main advantages, while they were concerned about body and health, the higher price of the products, the lack of information about the technologies and a general scepticism. The study also shows that North European participants were a bit more sceptical towards PEF and HPP products than the East European participants.

Texture changes of processed fruits and vegetables: potential use of high-pressure processing

In processed fruits and vegetables, changes in texture are strongly related to transformations in cell wall polymers due to enzymatic and non-enzymatic reactions. A major challenge is how to use recent advances in processing technologies and to adjust raw materials, ingredients and processes to improve texture of processed plant based foods. This review focuses on the plant cell wall structure and the processing dependent changes in plant cell walls with focus on enzymatic and non-enzymatic degradation of pectin. Stability as well as catalytic activity of two major plant endogenous pectin degrading enzymes, namely pectinmethylesterase and polygalacturonase, towards elevated pressure and temperature is reviewed. Finally, the effect of processing on texture of plant based foods and different approaches to improve the texture of processed plant based foods (i.e. preheating, phenolics, washing/dipping/infusion pretreatments, high-pressure pretreatments and genetic modification) are discussed.

High pressure treatment on the tofu fatty acids and acylglycerols content

Abstract Three batches of tofu were purchased from the local market. The samples were packaged under vacuum, and half of them subjected to a pressure in a range of 100 to 350 MPa at ambient temperature (22 °C) for 15 min, the rest were considered as control. The soy fat was extracted with hexane and the characterisation of fatty acids composition as methyl esters (FAME) and their diacyl–triacylglycerols (DAG, TAG) were analysed by Gas chromatography (GC). The tofu fat is low in saturated fatty acids (SFA, ∼ 16%) and high in polyunsaturated fatty acids (PUFA, ∼ 64%). The DAG content was lower than 10% and the highest value obtained for TAG was for the CN54 (∼ 60%), followed for the CN52 (∼ 28%) and CN50 (∼ 4%). No significant changes on the profile fat pattern have been found after the high pressure treatment in the assayed conditions. The ratios of PUFA/SFA and n-6/n-3 are 4 and 7 respectively. Tofu can be subjected to HP of 350 MPa without significant changes in its fat pattern. Industrial relevance Tofu is becoming an increasingly important international product outside its traditional markets. The use of high pressure processing for preservation purposes is a potential to retain or increase the nutritional value of foods of high relevance. This paper concentrates on the impact of high pressure on polyunsaturated acid and di-triacylglycerols. Interestingly no significant changes due to high pressure treatment could be observed marking this an attractive processing option.

Effects of High-Pressure Processing on the Safety, Quality, and Shelf Life of Ready-to-Eat Meats

Ready-to-eat (RTE) meats (low-fat pastrami, Strassburg beef, export sausage, and Cajun beef) were pressure treated at 600 MPa, 20°C, for 180 s to evaluate the feasibility of using high-pressure processing (HPP) for the safe shelf-life extension of these products. After processing, samples were stored at 4°C for 98 days during which time microbiological enumeration and enrichments were performed. Additionally, sensory analyses were undertaken to determine consumer acceptability and purchase intent over the duration of storage. Counts of aerobic and anaerobic mesophiles, lactic acid bacteria, Listeria spp., staphylococci, Brochothrix thermosphacta, coliforms, and yeasts and molds revealed that there were undetectable or low levels for all types of microorganisms throughout storage. Comparison of consumer hedonic ratings for unprocessed and processed meats revealed no difference in consumer acceptability, and no deterioration in the sensory quality was evident for any of the products tested during the study. Additionally, inoculated pack studies were conducted to determine if HPP could be used as a postlethality treatment to reduce or eliminate Listeria monocytogenes and thus assess the potential use of HPP in a hazard analysis critical control point plan for production of RTE meats. Inoculated samples (initial level of 104 CFU/g) were pressure treated (600 MPa, 20°C, for 180 s) and stored at 4°C, and survival of L. monocytogenes was monitored for 91 days. L. monocytogenes was not detected by plating methods until day 91, but selective enrichments showed sporadic recovery in three of the four products examined. The results show that HPP at 600 MPa, 20°C, for 180 s can extend the refrigerated shelf life of RTE meats and reduce L. monocytogenes numbers by more than 4 log CFU/g in inoculated product.

The Use of High-pressure Processing in the Production of Queso Fresco Cheese

: Three varieties of Queso Fresco cheese were produced: a control cheese made from raw milk, cheese made from pressure-treated milk, and cheese treated with high pressure after production. Sensory attributes, texture profile analysis, and composition were compared following 1 and 8 d of storage time. High-pressure treatment of cheese (400 MPa, 20 min, 20 °C) did not impart major textural and compositional changes; however, cheese made from pressure-treated milk contained more moisture and was less firm, less crumbly, and more sticky than the control and decreased in firmness during storage. High-pressure processing treatment of cheese can provide an alternative method for producing Queso Fresco-style cheese with acceptable textural attributes.

Use of High‐pressure Processing for Oyster Shucking and Shelf‐life Extension

ABSTRACT: Whole Pacific oysters (Crassostrea gigas) were processed using high‐pressure processing (HPP) treatment from 207 to 310 MPa at 0, 1, and 2 min and stored at &lt; 4 °C and evaluated over 27 d. The pH of HPP samples decreased slightly from 6.3 to 5.8 during storage while the control (hand‐shucked oysters) dropped to pH 4.1. Moisture content of the controls decreased slightly while HPP samples increased slightly. Pressure treatment did not significantly inhibit lipase activity during the shelf‐life study. HPP reduced initial microbial load by 2 to 3 logs and counts remained at a reduced level through the storage study. Descriptive evaluation showed that HPP‐treated oysters received higher quality scores than controls during the storage trial.

Survival of Escherichia coli O157:H7 during Storage in Pressure-Treated Orange Juice

The effect of a high-pressure treatment on the survival of a pressure-resistant strain of Escherichia coli O157:H7 (NCTC 12079) in orange juice during storage at 3°C was investigated over the pH range of 3.4 to 5.0. The pH of shelf-stable orange juice was adjusted to 3.4, 3.6, 3.9, 4.5, and 5.0 and inoculated with 108 CFU ml−1 of E. coli O157:H7. The orange juice was then pressure treated at 400 MPa for 1 min at 10°C or was held at ambient pressure (as a control). Surviving E. coli O157: H7 cells were enumerated at 1-day intervals during a storage period of 25 days at 3°C. Survival of E. coli O157:H7 during storage was dependent on the pH of the orange juice. The application of high pressure prior to storage significantly increased the susceptibility of E. coli O157:H7 to high acidity. For example, after pressure treatment, the time required for a 5-log decrease in cell numbers was reduced from 13 to 3 days at pH 3.4, from 16 to 6 days at pH 3.6, and from >25 to 8 days at pH 3.9. It is evident that the use of high-pressure processing of orange juice in order to increase the juice's shelf-life and to inactivate pathogens has the added advantage that it sensitizes E. coli O157:H7 to the high acid conditions found in orange juice, which results in the survival of significantly fewer E. coli O157:H7 during subsequent refrigerated storage.