Ultra-high Pressure Processing Research Articles

Effect of ultra-high pressure heat-assisted technology combined with L-cysteine on the color of ready-to-eat shrimp during storage

This study used ultra-high pressure processing (HPP) heat-assisted technology combined with L-cysteine (L-cys) to process ready-to-eat (RTE) shrimp. Subsequently, the effects of physical field and chemical modifications on the color of RTE shrimp were studied. The results showed that the RTE shrimp treated with HPP-Heat-L-cys showed better performance in terms of brightness value (65.25) and astaxanthin (AST) content (0.71 μg/g) during storage, maintaining the original color of RTE shrimp effectively. In addition, it was observed that the application of HPP-Heat-L-cys significantly delayed phenol oxidation, lipid oxidation, and Maillard reaction compared with traditional HPP or heat treatments. Specifically, the total phenolic content of RTE shrimp treated with HPP-Heat-L-cys was higher than that of other samples, but the TBARS and browning index were lower. Furthermore, HPP-Heat-L-cys could delay the production of dark products (such as 2-methylanthraquinone, p-benzoquinone, lipofuscin and melanin), ultimately safeguarding the color stability of RTE shrimp during storage.

Localization of an IgE epitope of glycinin A2 peptide chain.

One of the main allergens in soybeans is glycinin, which seriously impacts the normal lives of allergic people. Previous studies have confirmed that thermal processing and thermal processing combined with ultrahigh-pressure processing could significantly reduce the antigenicity of glycinin. The dominant antigen region of acidic peptide chain A2 of G2 subunit was located by phage display experiment. In this paper, overlapping peptides and alanine substitution techniques were used to explore the key amino acids that significantly affect the antigenicity of A2 peptide chain. The purity of peptide 1, peptide 2 and peptide 3 was identified by mass spectrometry and high-performance liquid chromatography, and the results showed that the purity of the synthesized overlapping peptide was more than 90%. SDS-PAGE showed that the peptide was successfully coupled with bovine serum albumin. The antigenicity of the coupling peptide was tested by ELISA and Dot-Blot, and the allergenicity was detected by reacting with the serum of patients with soybean globulin allergy. The results showed that peptide 3 has stronger antigenicity and sensitization. Alanine substitution technology allowed one to perform site-directed mutagenesis on peptide 3. Dot-Blot and ELISA tests showed that D259, E260, E261, Q263 and C266 may be the key amino acids that significantly affect the antigenicity of peptide 3. The research presented is of great significance for correctly guiding the production of safe food and preventing the occurrence of food allergic diseases. © 2023 Society of Chemical Industry.

Effect of ultrahigh pressure processing (UHP) on physicochemical properties, antioxidant activity and anti-inflammatory activity of insoluble dietary fiber from Pholiota nameko.

The aim of this study was to evaluate the effect of ultrahigh pressure processing (UHP) of 200, 300, 400, 500, 600 and 700MPa for 20, 40 and 30min on physicochemical andbioactive propertiesof the insoluble dietary fiber Pholiota nameko (PN-IDF). The results revealed that UHP were capable of decreasing the particle size of PN-IDF and binding phenolic content. Moreover, UHP technique had an improving effect on the bioaccessible phenolic content, the water-holding capacity, the oil-holding capacity and the nitrite ion adsorption capacity. Further, UHP technique presented a promoting effect on the antioxidant activity by scavenging ABTS or DPPH free radicals and increasing reducing power, and the anti-inflammatory activity by inhibiting carrageenan-induced paw edema on PN-IDF. Overall, this study well proved that UHP technology could improve the physicochemical and functional quality of PN-IDF, which could be used as a promising green technique for functional food ingredients processing.

Effect of ultra-high pressure pretreatment on the phenolic profiles, antioxidative activity and cytoprotective capacity of different phenolic fractions from Que Zui tea

This study aims to explore whether ultra-high pressure (UHP) pre-treatment strengthened the bioaccessibility and bioactivities of the free (QF), esterified (QE) and insoluble-bound phenolics (QIB) from Que Zui tea (QT). The results revealed that the extraction yields, the total phenolic (TPC) and total flavonoid contents (TFC) of three phenolic fractions from QT were markedly increased after ultra-high pressure (UHP) processing (p < 0.05). A total of 19 and 20 compounds were characterized and quantified in non- and UHP-treated QT, respectively, including the content of 6′-O-caffeoylarbutin (11775.68 and 13248.87 μg/g of dry extract) was highest in QF, the content of caffeic acid was highest in QE (2131.58 and 7362.99 μg/g of dry extract) and QIB (9151.89 and 10930.82 μg/g of dry extract). QF, QE and QIB from QT after UHP processing had better antioxidant, ROS scavenging, and anti-apoptosis effects. The possible mechanism of cytoprotective effect was related to Keap1-Nrf2 pathway.

Effects of Ozone Water Combined With Ultra-High Pressure on Quality and Microorganism of Catfish Fillets (Lctalurus punctatus) During Refrigeration.

This study described the quality and microbial influence on ozone water (OW) and ultra-high pressure (UHP) processing alone or in combination with refrigerated catfish fillets. The analysis parameters included total volatile base nitrogen (TVBN), thiobarbituric acid reactive substances (TBARs), chromaticity, microbial enumeration, 16S rRNA gene sequencing, electronic nose (E-nose), and sensory score. The study found that compared with the control (CK), ozone water combined with ultra-high pressure (OCU) delayed the accumulation of TVBN and TBARs. The results of sensory evaluation illustrated that OCU obtained a satisfactory overall sensory acceptability. The counting results suggested that compared to CK, OCU significantly (p < 0.05) delayed the stack of TVC, Enterobacteriaceae, Pseudomonas, lactic acid bacteria (LAB), and hydrogen sulfide-producing bacteria (HSPB) during the storage of catfish fillets. The sequencing results reflected that the dominant were Proteobacteria, Firmicutes, Bacteroidetes, and Actinobacteria at the phylum level, and the dominant were Acinetobacter, Pseudomonas, Lelliottia, Serratia, Shewanella, Yersinia, and Aeromonas at the genus level. The dominant was Acinetobacter in initial storage, while Pseudomonas and Shewanella were in anaphase storage. Based on the TVC and TVBN, the shelf life of catfish fillets was extended by at least 3 days compared to the control. In short, the combination of ozone water and ultra-high-pressure processing is a favorable strategy to control microbial quality and delay lipid oxidation during catfish storage.

Effect of ultra-high pressure treatment on the characteristics of a tea polysaccharide conjugate aqueous solution

Previous studies have shown that ultra-high pressure (UHP) processing technology to extract, prepare, and sterilize tea beverages (tea infusion) significantly increases the extraction rate of tea polyphenols (catechins), free amino acids, caffeine, and other small molecules in green tea, besides sterilizing and inactivating residual oxidases, such as polyphenol oxidase and peroxidase. UHP avoids the deterioration of color and aroma, as high-quality green tea infusions were obtained with nutritional value and flavor quality close to the original tea. However, the effect of UHP on polysaccharides in green tea infusions is unclear. The water-extracted tea polysaccharide conjugates (TPC-W) and alkali-extracted tea polysaccharide conjugates (TPC-A) from low-grade green tea were subjected to a UHP treatment of 100, 300, and 500 MPa for 5, 12, and 25 min. The circular dichroism (CD) spectra results showed that UHP transformed the secondary structure of the TPC-W and TPC-A from compact and ordered α-helices and β-sheets to disordered β-turns and random coils; one component of TPC-A was dissociated into two components. The absolute values of the zeta potential of TPC-W treated with 100, 300, and 500 MPa increased by 2.4–5.6, 5.3–8.0, and 5.5–9.1 mV, while those of TPC-A increased by 0.5–2.8, 3.5–5.5, and 4.8–6.9 mV, respectively. The stability of TPC-W and TPC-A aqueous solutions treated with 300 and 500 MPa was enhanced during storage at 5°C. These findings will contribute to applying UHP for tea beverage processing and in-depth investigations on the physiochemical properties of TPC, particularly the protein moiety.

Optimization of the Enzymatic Hydrolysis Assisted by Ultra-high Pressure Processing of Alaska Pollock Frame for Improving Flavour

ABSTRACT In order to improve the flavor of aquatic enzymatic hydrolysate, this study determined the effect of ultra-high pressure processing (UHP) coupled with enzymatic hydrolysis on the flavor of Alaska pollock frame (APF) hydrolysates. The optimal conditions for UHP enzymatic hydrolysis were as follows: pressure time was 60 min, pH value was 7.5, and pressure was 150 MPa. The content of soluble peptide, total-free amino acid, and delicious amino acid (DAA) content of atmospheric pressure and UHP hydrolysates were 11.37 vs 16.70 mg/mL, 5 528 vs 6 234 mg/100 g, and 2145 vs 2411 mg/100 g, respectively. The major compounds in the enzymatic hydrolysates of UHP included seven types of ketones (18.31%), 8 types of aldehydes (6.35%), 3 types of alcohols (2.61%), one type of ester (0.38%), and one type of furan (7.89%). The results of electronic tongue (e-tongue) demonstrated good agreement with gas chromatography-mass spectrometry (GC-MS) analysis. In conclusion, UHP enzymatic hydrolysis can be a potential tool to improve the flavor compounds of hydrolysates.

Effect of Ultra-High Pressure Technology on Isomerization and Antioxidant Activity of Lycopene in Solanum Lycopersicum

To evaluate the influence of the Ultra-High Pressure processing (UHP) on the isomerization and antioxidant activity of lycopene in tomatoes (Solanum lycopersicum), High Performance Liquid Chromatography (HPLC) and Ultraviolet-Visible Spectroscopy (UV-Vis) were used to separate and identify the isomer of lycopene. The scavenging activities against DPPH∙and∙OH present samples with and without UHP treatment were tested with ascorbic acid as positive control. Full wavelength scanning figure showed that a characteristic absorption peak was created at 361 nm, which was caused by trans-lycopene isomerizing into cis isomer. HPLC analysis found that five peaks (Rt = 19.082, 13.307, 9.790, 8.123, 7.207 min) were produced after UHP treatment, which were further identified by UV-Vis and four peaks among them showed a strong absorption peak at 361 nm which was in accordance with the UV-Vis spectroscopy of cis-lycopene. The total antioxidant, capable of scavenging hydroxyl radicals·OH and DPPH·radical of lycopene treated by UHP, were all higher than that of control and lycopene without UHP treated. Taken together, UHP treatment played the role in cis-trans conversion of lycopene and could also improve the antioxidant activity of lycopene oleoresin with a dose-dependent fashion.

Application of Ultra-high Pressure Processing Technology

High pressure processing is an innovation for the traditional food processing and preservation method. Since the method of ultra-high pressure processing (HPP) exerts a very little influence on the covalent bond of food, its influence on the nutrition, taste, and texture of food is minimized. However, HPP food is perishable in long distance transportation and sales process. Since food freshness directly affects the final demand in market, how to use the appropriate strategy to manage commodity stocks effectively during the long time and distance in food transportation and match the supply and demand of HPP food to improve the competitiveness of companies are the challenges faced by HPP food companies in upstream and downstream supply chain. This paper describes of the different features of HPP foods compared to that of traditional processed foods, and analyzes the collaboration of HPP foods supply chain members.

Ultra-high pressure effects on color, volatile organic compounds and antioxidants of wholegrain brown rice (Oryza sativa L.) during storage: A comparative study with high-intensity ultrasound and germination pretreatments

Abstract Wholegrain brown rice (WBR) with significantly enhanced quality attributes has been recently achieved after ultra-high pressure (UHP) processing, but the process-induced changes in physicochemical parameters following subsequent storage for UHP-treated WBR are scarcely documented. So this work was designed to investigate the effects of UHP treatments (0.1–450 MPa/10 min) on chemical composition, microstructure, and the changes in chemical reactions during storage (20 days/30 °C) as indicated by volatile profiling, color development, and antioxidant activities for WBR grains, compared to high-intensity ultrasound (HIU) and germination (GER) pretreatments. Results showed that significant variation in physicochemical properties was caused by both processing approaches and storage duration. Color changes (a*, b*, L*, and ΔE) were slightly noticeable after storage for all WBR samples, and UHP-treated grains represented clearly visible browning reactions. In addition, hierarchically clustered heatmap suggested that volatile fingerprinting could be preliminarily separated according to different pretreatments and storage duration. After immediate treatments, total antioxidant activities presented a decrease by 14–28% for all treated grains compared to the unprocessed samples. Within storage process, GER and HIU samples showed steadily declining trends for antioxidant activities whereas a fluctuation was observed in UHP-treated grains. Besides, samples treated by 350/450 MPa maintained more antioxidants (91–102%) than the control (83–87%), GER (64–76%) and HIU (76–88%) samples at the end of storage. Multivariate analysis revealed a close relationship between color changes and antioxidant activity. These results indicated the necessity of a complete evaluation for possible processing effects on physicochemical and nutritional characteristics of WBR grains within the entire process extending immediate treatments to its prolonged storage and consumption, in order to achieve better quality control using the optimized processing parameters. Industrial relevance The selected emerging techniques including UHP, HIU and GER allow the acquisition of WBR products with improved texture and cooking properties as well as the enrichment of bioactive components. Nevertheless, the processed WBR grains must be subjected to a storage process before consumption. A more comprehensive understanding of the effects of newly-developed techniques on quality characteristics of WBR grains contributes to better control of products quality, particularly extending from immediate effects to the prolonged storage.

Ultrahigh Pressure Processing Produces Alterations in the Metabolite Profiles of Panax ginseng.

Ultrahigh pressure (UHP) treatments are non-thermal processing methods that have customarily been employed to enhance the quality and productivity of plant consumables. We aimed to evaluate the effects of UHP treatments on ginseng samples (white ginseng: WG; UHP-treated WG: UWG; red ginseng: RG; UHP-treated RG: URG; ginseng berries: GB; and UHP-treated GB: UGB) using metabolite profiling based on ultrahigh performance liquid chromatography-linear trap quadrupole-ion trap-tandem mass spectrometry (UHPLC-LTQ-IT-MS/MS) and gas chromatography time-of-flight mass spectrometry (GC-TOF-MS). Multivariate data analyses revealed a clear demarcation among the GB and UGB samples, and the phenotypic evaluations correlated the highest antioxidant activities and the total phenolic and flavonoid compositions with the UGB samples. Overall, eight amino acids, seven organic acids, seven sugars and sugar derivatives, two fatty acids, three notoginsenosides, three malonylginsenosides, and three ginsenosides, were identified as significantly discriminant metabolites between the GB and UGB samples, with relatively higher proportions in the latter. Ideally, these metabolites can be used as quality biomarkers for the assessment of ginseng products and our results indicate that UHP treatment likely led to an elevation in the proportions of total extractable metabolites in ginseng samples.

The importance of ultrahigh pressure processing over the quality of the extracted oil from peony seeds (Paeonia suffruticosa Andr.)

The influence of extraction pressure on peony seeds (Paeonia suffruticosa Andr.) oil yield and quality was investigated using GC–MS, and the results indicated that the extraction of peony seeds oil under atmospheric pressure had the lowest oil yield and led to the absence of 9,12,15-octadecatrienoic acid in the oil. Ultrahigh pressure (UHP) of 350, 400, 450, 500 and 550MPa was used in this study and the analysis demonstrated that all the extracted peony seeds oils using UHP technology had the common compounds including hexadecanoic acid, 9,12-octadecadienoic acid, 9,12,15-octadecatrienoic acid, and octadecanoic acid, but their proportions in the extracted oils greatly differed. Although the oil yield was the highest, the extraction at a lower pressure of 350MPa achieved the greatest saturated fatty acids content of 49.49% and also the highest fatty acids number of 11, which might be due to the activated enzymes during the extraction. In contrast, the unsaturated fatty acids content in the extracted oil was up to be the highest of 87.57% when the extraction pressure of 500MPa was used, and its corresponding fat acidity was found to the lowest level of 3.5mg 100g−1 among all the extracted oils. This study suggests that the both oil yield and, in particular the oil quality are greatly sensitive to the extraction pressure.

Effect of onion (Allium cepa) ultra-high pressure processing and hot water extracts on the serum cholesterol level in high cholesterol-fed rats

Effects of high pressure-processed onion extracts (OHP) on high cholesterol diet (HCD)-fed rats were investigated using 5 groups of normal diet, HCD, HCD with OHP (medium-dose (OHP-1) or high-dose (OHP-2)), and HCD with onion hot water extract (OHW) as a control for 6 weeks. OHP increased serum AST, total cholesterol, and HDL and LDL cholesterol levels. The LDL cholesterol level was 7.76 mg/dL in the normal diet group and 155.06 mg/dL in the HCD-fed group. Treatment with 8.1 g/kg/day OHP reduced LDL levels to 82.38 mg/ dL. Total hepatic lipid and cholesterol levels were reduced in HCD-fed and OHP treated rats, compared with HCD- fed rats. Fecal lipid and cholesterol levels were significantly (tonal lipid, p<0.05; cholesterol, p<0.05) increased in HCD-fed rats, compared with controls, and OHP treatment increased lipid and cholesterol excretion. OHP prevented hyperlipidemia by improving lipid metabolism via decreased liver lipid contents and increased fecal lipid excretion.

Research on the Sealing Structure of Prestressed Wire-Wound Ultra-High Pressure Vessel

As an emerging industry, ultra-high biological processing technology enjoys great potential and vast development prospects. Design and manufacture of the pressure equipment has always been a core problem because of ultra-high pressure processing environment. The finite element analysis software ANSYS is used to analyses the working stress distribution and deformation of a combined self-sealing structure according to an ultra-high pressure vessel. The sealing situation is evaluated and the dangerous position of axial seal is calculated which has a certain guiding significance on optimal structure design of container end seal in the future.

Effect of ultra high-pressure processing on microorganisms and ginsenosides of Panax ginseng

To study the feasibility of the application of ultra high-pressure processing (UHPP) as an anticorrosion and anti-mould method by comparing the total numbers of bacteria and mould colonies and the content of ginsenosides before and after UHPP. The total numbers of bacteria and moulds colony were determined by microbiological test method. The contents of 12 ginsenosides were determined by HPLC. Under the three selected conditions, the total number of bacterial colony decreased significantly, while the mould was not detected in UHPP samples; and the contents of 12 ginsenosides were increased significantly in methanol extracts and water extracts. UHPP not only shows anticorrosion and anti-mould effects, but also enhances the leaching rate of ginsenosides. It is a highly effective, safe and environmental friendly anticorrosion and anti-mould technique for Ranax ginseng worth in-depth study.

Application of Ultra High Pressure (UHP) in Starch Chemistry

Ultra high pressure (UHP) processing is an attractive non-thermal technique for food treatment and preservation at room temperature, with the potential to achieve interesting functional effects. The majority of UHP process applications in food systems have focused on shelf-life extension associated with non-thermal sterilization and a reduction or increase in enzymatic activity. Only a few studies have investigated modifications of structural characteristics and/or protein functionalities. Despite the rapid expansion of UHP applications in food systems, limited information is available on the effects of UHP on the structural and physicochemical properties of starch and/or its chemical derivatives included in most processed foods as major ingredients or minor additives. Starch and its chemical derivatives are responsible for textural and physical properties of food systems, impacting their end-use quality and/or shelf-life. This article reviews UHP processes for native (unmodified) starch granules and their effects on the physicochemical properties of UHP-treated starch. Furthermore, functional roles of UHP in acid-hydrolysis, hydroxypropylation, acetylation, and cross-linking reactions of starch granules, as well as the physicochemical properties of UHP-assisted starch chemical derivatives, are discussed.

초고압 처리에 의한 이유식 가공 및 특성

반고형 형태의 이유식 제조에 가장 적합한 물성을 부여하는 점증제를 선정하기 위해 쌀가루, 변성전분 1 및 변성전분 2를 4%를 첨가하거나 0.3% 펙틴을 첨가한 이유식을 550 MPa 압력에서 3분 동안 초고압 처리하여 점도를 측정하고 관능평가를 실시한 결과, 쌀가루를 첨가한 바나나와 사과 이유식 모두 색, 흐름성 및 질감에서 가장 선호도가 높았을 뿐 아니라 시판 이유식과 가장 유사한 점도를 보여 반고형 상태의 이유식 제조에 쌀가루가 점증제로 적합하였다. 점증제로 선정된 쌀가루를 4%, 6% 및 8% 첨가하여 제조한 이유식을 450 MPa과 550 MPa의 압력 조건에서 1, 3, 5분 처리한 결과, 쌀가루 첨가 비율이 높아질수록 점도와 색도의 밝기는 증가하였고, pH와 당도에서 유의적인 차이는 없었다. 또한 초고압 처리 조건에서 압력의 변화와 처리시간의 증가에 따른 유의적인 차이를 보이지 않는다. 즉 초고압 처리가 이유식의 물성에 영향을 크게 미치지 않으므로 경제성 및 점증제의 호화 정도를 고려하여 이유식 제조를 위한 초고압 처리 조건은 550 MPa, 3 min이 가장 적당한 처리 조건으로 판단되었다. In the manufacture of baby food in the form of semi-solid to give the most suitable rheological properties to select thickener, 4% of rice flour, modified starch 1 and modified starch or 0.3% pectin added to baby food. After 3 minutes at a pressure 550 MPa high pressure processing(HPP), sensory evaluation conducted to measure the viscosity results, the addition of rice flour, baby food bananas and apples all the color, texture, flow properties and high affinity for most commercial baby food as well as the most likely to show the viscosity of semi-solid state in the manufacture of baby food there were rice flower most suitable. The baby food that 4%, 6% and 8% of rice flower added as thickener were high pressure processing at 450 MPa and 550 MPa pressure and 1, 3 and 5 min conditions. In results, the higher added percentage of rice flower, the viscosity and lightness were increased, pH and sugar content were not significantly different from. In addition, ultra-high pressure processing conditions and the processing time for a change in pressure due to the increase is not significantly different. Because of high-pressure processing does not significantly affect the physical properties of the baby food, consideration of the economy and gelatinization degree, high-voltage processing conditions for the manufacture of baby food 550 MPa, 3 min was considered the most suitable processing conditions.

Physicochemical properties and bioactivity of brown seaweed fucoidan prepared by ultra high pressure-assisted enzyme treatment

The effects of ultra-high pressure (UHP, 100 MPa, 40, 24 h) processing and enzyme treatment on the physicochemical properties and anticoagulant activity of fucoidan obtained from Undaria pinnatifida sporophyll (UPS) were investigated. Crude UPS fucoidan (FUPS) with an average MW of 877 kDa was slightly depolymerized by UHPassisted Tunicase treatment, yielding fucoidan with a lower MW (600–800 kDa). UHP-enzyme treatment decreased the sulfate, fucose and galactose contents of FUPS but increased its glucose content. From FT-IR spectrum, UHP-enzyme treatment was found not to cause a structural change on S=O and C-O-S. After UHP-enzyme treatment, the sulfate content and average MW of FUPS decreased with the increase of Tunicase concentration. It was found that among the UHP-enzyme-treated fucoidans, FUPS-T0.3-U (Tunicase 0.3% treatment+UHP treatment) possessed the highest anticoagulant activity. FUPS-T0.3-U appeared to inhibit blood coagulation via intrinsic pathway. With the increase of sulfate content in FUPS, activated partial thromboplastin time (APTT) and thrombin time (TT) showed a tendency of increase. APTT and TT had the highest values in FUPS-T0.3-U in which the sulfate concentration was 24%, but on the contrary decreased at a sulfate concentration of above 24%. This result indicates that there is an optimum sulfate concentration for the anticoagulant activity of fucoidan. Consequently, UHP-assisted enzymatic treatment was found to be helpful for the improvement of anticoagulant activities of fucoidan.

Impact Analysis of Ultrahigh Pressure Treatment Pesticide Residues in Vegetables on near Infrared Spectroscopy Detection

In order to simplify the process of detecting pesticide residues in vegetables, reducing detection time to find a more efficient detection method, ultrahigh pressure processing technique was applied to NIR detection experiments on dimethoate residues in Chinese cabbage, the spectral data was pre-processed and optimized and a spectrum model was established. The results show that: ultrahigh-pressure extraction process did not affect the absorption of near infrared spectroscopy of extraction reagent acetone. A PLS model on near-infrared spectroscopy of samples within the range of 4100-11000cm-1 was established, obtaining a correlation coefficient R of 87.14%, Rank of 9 and RMSECV of 0.139. Residual concentration of 10-4-10-5 has a small relative error, the prediction is better. Further processing and selection of samples will expand the range of predicted concentration.

Screening for Listeria monocytogenes surrogate strains applicable to food processing by ultrahigh pressure and pulsed electric field.

Ultrahigh pressure (UHP) and pulsed electric field (PEF) are emerging processing technologies developed to enhance the safety while maintaining the fresh-like quality of food. For each food and process combination, a pathogen of concern (i.e., target pathogen) must be determined, and a low-risk microorganism that serves as the pathogen surrogate for process validation must be identified. The objective of this study was to identify a surrogate for Listeria monocytogenes for UHP and PEF process validation. Potential surrogates tested include four Lactobacillus spp., a Pediococcus sp., and a Listeria innocua strain. These were compared with nine L. monocytogenes strains, with regard to sensitivity to UHP and PEF processing. For UHP treatment, the strains were suspended in citrate-phosphate buffer (pH 7.0 or 4.5), sweet whey, or acidified whey and pressure processed at 500 MPa for 1 min. For PEF treatment, the strains were suspended in NaCl solution, acid whey, or sweet whey and processed at 25 kV/cm. The lethality of UHP or PEF treatment varied considerably, depending on medium types and pH and the treated strain. Treating the tested microorganisms with UHP inactivated 0.3 to 6.9 log CFU/ml for L. monocytogenes strains and 0.0 to 4.7 log CFU/ml for the potential surrogates. When PEF was employed, populations of tested microorganisms decreased < 1.0 to 5.3 log CFU/ml. L. monocytogenes V7 and OSY-8578 were among the most resistant strains to UHP and PEF treatments, and thus are candidate target strains. Lactobacillus plantarum ATCC 8014 demonstrated similar or greater resistance compared with the target organisms; therefore, the bacterium is proposed as a surrogate of L. monocytogenes for both processes under the conditions specified in the food matrices tested in this study.