Bacillus cereus spores and Staphylococcus aureus sub. aureus vegetative cells inactivation in human milk by high-pressure processing

Application of pressure homogenization on whole human milk pasteurized by high hydrostatic pressure: Effect on protein aggregates in milk fat globule membrane and skim milk phases

This study explored the impact of homogenization (at pressures of 16, 30, and 45 MPa) on both raw and high hydrostatic pressure (HHP)-treated human milk (HM). It focused on protein compositions and binding forces of soluble and insoluble fractions for both milk fat globule membrane (MFGM) and skim milk. Mild homogenization of HHP-treated milk increased lactoferrin (LF) levels in the insoluble fractions of both MFGM and skim milk, due to insoluble aggregation through hydrophobic interactions. Intense homogenization of HHP-treated milk decreased the LF level in the MFGM fractions due to the LF desorption from the MFGM, which increased LF level in the insoluble skim milk fraction. Homogenized-HHP treated milk showed noticeably higher casein (CN) level at the MFGM compared to homogenized-raw milk, attributed to HHP effect on CN micelles. Overall, the combined use of HHP and shear-homogenization should be avoided as it increased the biological proteins in insoluble fractions.

New alternatives to holder pasteurization in processing donor milk in human milk banks

Infectious and toxicological risks are the main potential hazards that operators of Human Milk Banks (HMBs) encounter and must eliminate. HMBs are trying to implement procedures that allow to manage and sanitize human milk without altering significantly its nutritional and biologically protective components, obtaining a product characterized by a valid balance between safety and biological quality. The history of human milk processing is linked to the origins of HMBs themselves. And although other forms of sterilization were used originally, pasteurization soon became the recognized most effective means for sanitizing milk: all the milk that arrives at the HMB must be pasteurized. Holder pasteurization (HoP) is the most used methodology, and it is performed using low temperature and long time (+62.5°C for 30 min). With HoP some bioactive milk components are lost to varying degrees, but many other precious bioactive compounds are completely or partially preserved. To improve the quality of human milk processed by HMBs, maintaining in the meantime the same microbiological safety offered by HoP, new technologies are under evaluation. At present, High-Temperature Short-Time pasteurization (HTST) and High-Pressure Processing are the most studied methodologies. HTST is already utilized in some HMBs for daily practical activity and for research purposes. They seem to be superior to HoP for a better preservation of some nutritional and biologically protective components. Freeze-drying or lyophilization may have advantages for room temperature storage and transportation. The aim of this study is to evaluate the advancement regarding the processing of DHM with a literature search from 2019 to 2022. The effects of the new technologies on safety and quality of human milk are presented and discussed. The new technologies should assure microbiological safety of the final product at least at the same level as optimized HoP, with an improved preservation of the nutritional and bioactive components of raw human milk.

Breast milk preservation: thermal and non-thermal processes and their effect on microorganism inactivation and the content of bioactive and nutritional compounds

Human Breast Milk (HBM) is widely acknowledged as the best nutritional source for neonates. Data indicates that, in 2019, 83.2% of infants in the United States received breast milk at birth, slightly reducing to 78.6% at 1 month. Despite these encouraging early figures, exclusive breastfeeding rates sharply declined, dropping to 24.9% by 6 months. This decline is particularly pronounced when direct breastfeeding is challenging, such as in Neonatal Intensive Care Units (NICU) and for working mothers. Given this, it is vital to explore alternative breast milk preservation methods. Technologies like Holder Pasteurization (HoP), High-Temperature Short-Time Pasteurization (HTST), High-Pressure Processing (HPP), UV radiation (UV), and Electric Pulses (PEF) have been introduced to conserve HBM. This review aims to enhance the understanding of preservation techniques for HBM, supporting the practice of extended exclusive breastfeeding. It explicitly addresses microbial concerns, focusing on critical pathogens like Staphylococcus aureus, Enterococcus, Escherichia coli, Listeria monocytogenes, and Cytomegalovirus, and explores how various preservation methods can mitigate these risks. Additionally, the review highlights the importance of retaining the functional elements of HBM, particularly its immunological components such as antibodies and enzymes like lysozyme and Bile Salt Stimulated Lipase (BSSL). The goal is to provide a comprehensive overview of the current state of HBM treatment, critically assess existing practices, identify areas needing improvement, and advocate for extended exclusive breastfeeding due to its vital role in ensuring optimal nutrition and overall health in infants.

Integral Use of Red Wine Pomace after Hydrostatic High Pressure: Application of Two Consecutive Cycles of Treatment

The influence of applying hydrostatic high pressure (HHP) to red grape pomace cv. Tempranillo was studied to obtain an ingredient rich in bioactive compounds for the manufacture of food products. Four treatments were investigated: (i) 600 MPa/1 s; (ii) 600 MPa/300 s, and other two treatments with 2 cycles of HHP: (iii) 2 cycles of 600 MPa/1 s; and (iv) 1 first cycle of 400 MPa/1 s and a second cycle 600 MPa/1 s. Treated pomace was stored at different temperatures (4 and 20 °C). The application of two consecutive cycles had no effect on the microorganisms' inactivation compared to only one cycle. Immediately after HHP, the phenolic compounds content was maintained. However, HHP had no influence on the polyphenol oxidase enzyme (PPO), and so the phenolic compounds were significantly reduced during storage. Hence, the shelf-life of red grape pomace was significantly reduced at both temperatures, although phenolic compounds were better preserved under refrigeration than at room temperature.

Characterization of protein aggregates in cream and skimmed human milk after heat and high-pressure pasteurization treatments

Preservation processes applied to ensure microbial safety of human milk (HM) can modify the native structure of proteins and their bioactivities. Consequently, this study evaluated the effect of pasteurization methods (Holder pasteurization, high-temperature short-time (HTST), and high hydrostatic pressure (HHP)) of whole human milk (HM) on protein aggregates in skim milk and cream fractions. For heat-treated whole milk, insoluble protein aggregates at milk fat globule membrane (MFGM) were formed by disulfide and non-covalent bonds, but insoluble skim milk protein aggregates were only stabilized by non-covalent interactions. Contrary to heat treatment, the insolubilization of main proteins at the MFGM of HHP-treated HM was only through non-covalent interactions rather than disulfide bonds. Moreover, only heat treatment induced the insoluble aggregation of ⍺-lactalbumin. Overall, compared to heat treatment, HHP produced a milder effect on protein aggregation, validating the use of this process to better preserve the native state of HM bioactive proteins.

Effect of Single and Two-Cycles of High Hydrostatic Pressure Treatment on the Safety and Quality of Chicken Burgers

The aim of this study was to evaluate the effect of two cycles of high hydrostatic pressure (HHP) treatment on chicken burgers after storage at refrigeration (4 °C) for 15 days, in comparison with the application of a single cycle of high hydrostatic pressure treatment, as well as compared with non-treated burgers. Samples were treated at 400 and 600 MPa and a single or two cycles were applied. The results showed that mesophilic, psychrotrophic molds, yeast, and coliforms were significantly reduced by HHP treatment (p < 0.05), 600 MPa/1 s (2 cycles) leading to the maximum inactivation. Concerning color parameters, a significant increase in lightness/paleness (L*) and a reduction in redness (a*) and yellowness (b*) (p < 0.05) was observed in samples as 600 MPa were applied. Moreover, 600 MPa/1 s (2 cycles) caused the highest differences in the meat color (ΔE processing) of the chicken burgers. No HHP treatment significantly affected the degree of oxidation of samples (p > 0.05). However, 600 MPa/1 s (2 cycles) samples showed the highest values of TBA RS content after 15 days of storage (p < 0.05). Finally, the appearance, odor, taste, and global perception of cooked burgers were similar in all groups (p < 0.05). Therefore, treatments at 600 MPa produced a significant reduction in microbial counts but modified the color; however, the discoloration effect in the cooked burgers was not noticed by panelists.

High-Pressure Processing of Human Milk: A Balance between Microbial Inactivation and Bioactive Protein Preservation

BACKGROUND

Donor human milk banks use Holder pasteurization (HoP; 62.5°C, 30 min) to reduce pathogens in donor human milk, but this process damages some bioactive milk proteins.

OBJECTIVES

We aimed to determine minimal parameters for high-pressure processing (HPP) to achieve >5-log reductions of relevant bacteria in human milk and how these parameters affect an array of bioactive proteins.

METHODS

Pooled raw human milk inoculated with relevant pathogens (Enterococcus faecium, Staphylococcus aureus, Listeria monocytogenes, Cronobacter sakazakii) or microbial quality indicators (Bacillus subtilis and Paenibacillus spp. spores) at 7 log CFU/mL was processed at 300-500 MPa at 16-19°C (due to adiabatic heating) for 1-9 min. Surviving microbes were enumerated using standard plate counting methods. For raw milk, and HPP-treated and HoP-treated milk, the immunoreactivity of an array of bioactive proteins was assessed via ELISA and the activity of bile salt-stimulated lipase (BSSL) was determined via a colorimetric substrate assay.

RESULTS

Treatment at 500 MPa for 9 min resulted in >5-log reductions of all vegetative bacteria, but <1-log reduction in B. subtilis and Paenibacillus spores. HoP decreased immunoglobulin A (IgA), immunoglobulin M (IgM), immunoglobulin G, lactoferrin, elastase and polymeric immunoglobulin receptor (PIGR) concentrations, and BSSL activity. The treatment at 500 MPa for 9 min preserved more IgA, IgM, elastase, lactoferrin, PIGR, and BSSL than HoP. HoP and HPP treatments up to 500 MPa for 9 min caused no losses in osteopontin, lysozyme, α-lactalbumin and vascular endothelial growth factor.

CONCLUSION

Compared with HoP, HPP at 500 MPa for 9 min provides >5-log reduction of tested vegetative neonatal pathogens with improved retention of IgA, IgM, lactoferrin, elastase, PIGR, and BSSL in human milk.

New Insights into the Application of High-Pressure Processing and Storage Time and Temperature to Sliced Iberian Chorizo

Producing dry-cured meats with relatively high a_w and pH allows companies to cut costs to the detriment of microbial control. The purpose of this study was to evaluate for the first time the effect of High Processing Pressure (HPP) and storage temperature on the microbial counts, instrumental color, oxidation and sensory characteristics of sliced Iberian chorizo with high a_w and pH. First, 600 MPa was applied for 480 s to sliced chorizo with a_w: 0.88 and pH: 6.01, and the treated and untreated samples were stored at 4 or 20 °C for 90 or 180 days. HPP, storage time and storage at 20 °C were successful at decreasing the microbial counts that were initially high. HPP and the storage temperature had a limited detrimental effect, whereas the storage time had a marked adverse effect on oxidation and some sensory traits. Despite the high a_w and pH, no safety issues arose initially or during the storage at 4 or 20 °C. In conclusion, for chorizo with high a_w and pH favoring high microbial counts, HPP may be an effective hurdle without a noticeable detrimental effect, and the economically convenient storage at 20 °C might be beneficial despite causing moderate quality loss.

Transcriptome analysis reveals the molecular mechanism of cinnamaldehyde against Bacillus cereus spores in ready-to-eat beef

The purpose of this study was to investigate the antibacterial effect and mechanism of cinnamaldehyde on Bacillus cereus spores in ready-to-eat beef. The colour difference and texture of the ready-to-eat beef supplemented with cinnamaldehyde did not differ greatly from the colour and texture of the blank beef. However, cinnamaldehyde has an effective antibacterial effect on the total number of bacterial colonies and B. cereus spores in ready-to-eat beef. Transmission electron microscopy (TEM) analysis revealed that the cell membrane of B. cereus was disrupted by cinnamaldehyde, leading to leakage of intracellular components. Transcriptome sequencing (RNA-seq) indicated that the B. cereus spore resistance regulation system (sigB, sigW, rsbW, rsbV, yfkM and yflT) and phosphoenolpyruvate phosphotransferase system (PTS) (ptsH, ptsI and ptsG) respond positively to cinnamaldehyde in an adverse environment. Intracellular disorders due to damage to the cell membrane involve some transporters (copA, opuBA and opuD) and some oxidative stress systems (ywrO, scdA and katE) in the regulation of the body. However, downregulation of K⁺ transport channels (kdpD and kdpB), osmotic pressure regulation (opuE) and some oxidative stress (norR and srrA)-related genes may accelerate spore apoptosis. In addition, cinnamaldehyde also effectively inhibits the spore germination-related genes (smc, mreB and gerE). This study provides new insights into the molecular mechanism of the antibacterial effect of cinnamaldehyde on B. cereus spores in ready-to-eat beef.

Current progress of emerging technologies in human and animals' milk processing: Retention of immune-active components and microbial safety

Human milk and commercial dairy products play a vital role in humans, as they can provide almost all essential nutrients and immune-active components for the development of children. However, how to retain more native immune-active components of milk during processing remains a big question for the dairy industry. Nonthermal technologies for milk processing are gaining increasing interest in both academic and industrial fields, as it is known that thermal processing may negatively affect the quality of milk products. Thermosensitive components, such as lactoferrin, immunoglobulins (Igs), growth factors, and hormones, are highly important for the healthy development of newborns. In addition to product quality, thermal processing also causes environmental problems, such as high energy consumption and greenhouse gas (GHG) emissions. This review summarizes the recent advances of UV-C, ultrasonication (US), high-pressure processing (HPP), and other emerging technologies for milk processing from the perspective of immune-active components retention and microbial safety, focusing on human, bovine, goat, camel, sheep, and donkey milk. Also, the detailed application, including the instrumental design, technical parameters, and obtained results, are discussed. Finally, future prospects and current limitations of nonthermal techniques as applied in milk processing are discussed. This review thereby describes the current state-of-the-art in nonthermal milk processing techniques and will inspire the development of such techniques for in-practice applications in milk processing.

Inactivating Food Microbes by High-Pressure Processing and Combined Nonthermal and Thermal Treatment: A Review

High-pressure processing (HPP) is a mild technology alternative to thermal pasteurization and sterilization of different food products. HPP has emerged to provide enormous benefits to consumers, i.e., mildly processed food and additive-free food. It effectively retains bioactive compounds and extends the shelf life of food commodities by inactivating bacteria, yeast, mold, and virus. The limitation of HPP in inactivating spores can be overcome by using other thermal and nonthermal processing sequentially or simultaneously with HPP. This review summarizes the applications of HPP in the fruits and vegetables, dairy, meat, fish, and poultry sector. It also emphasizes microbial food safety and the effectiveness of HPP in the load reduction of microorganisms. Comprehensive information about the synergistic effect of HPP with different techniques and their effectiveness in ensuring food safety is reported. The summarized data would be handy to interested researchers and industry personnel.

Antibody-conjugated liposomes loaded with indocyanine green for oral targeted photoacoustic imaging-guided sonodynamic therapy of Helicobacter pylori infection

Helicobacter pylori is a causative factor of various gastrointestinal tract diseases. As clinical antibiotic-based therapy for H. pylori infection might induce bacterial drug resistance, the in vivo eradication of H. pylori remains a huge challenge. In the present study, monoclonal antibody-conjugated liposomes loaded with indocyanine green (ICG) (HpAb-LiP-ICG) were successfully developed for targeted photoacoustic (PA) imaging-guided sonodynamic therapy (SDT) of H. pylori infection in vivo. HpAb-LiP-ICG showed high stability and favorable biocompatibility in acidic environment (pH 1.5) and was used for treating H. pylori-infected mice through oral administration. PA imaging showed that HpAb-LiP-ICG could precisely recognize and target H. pylori in the stomach. Following the targeting of HpAb-LiP-ICG to H. pylori, ICG was activated to generate singlet oxygen (¹O₂) for eliminating H. pylori under ultrasound (US) irradiation. Pathological analysis revealed that the HpAb-LiP-ICG-mediated SDT eradicated H. pylori without unintended toxicity to normal tissues. In conclusion, the HpAb-LiP-ICG-mediated SDT might shed new light on treating H. pylori infection, indicating the clinical translational prospects of this therapy in near future. STATEMENT OF SIGNIFICANCE: Traditional antibiotic-based therapy for Helicobacter pylori infections suffers from the risk of drug resistance. To meet this challenge, a monoclonal antibody-conjugated nanoliposome loaded with indocyanine green (ICG) (HpAb-LiP-ICG) was successfully developed, and efficient eradication of H. pylori was achieved in vivo by visual sonodynamic therapy (SDT). HpAb-LiP-ICG exhibited biocompatibility, targeting, and stability in the acidic microenvironment. Under ultrasound (US) irradiation in vitro, the HpAb-LiP-ICG nanoliposomes accumulated on the surface of H. pylori were activated to produce adequate singlet oxygen (¹O₂) to eliminate H. pylori. Gastric mucous tissues infected with H. pylori recovered to the normal state after HpAb-LiP-ICG-mediated SDT without side effects, thus highlighting the clinical translational prospects of the prepared HpAb-LiP-ICG nanoliposome in near future.

Effects of High-Pressure Processing, UV-C Irradiation and Thermoultrasonication on Donor Human Milk Safety and Quality

Holder pasteurization (HoP) is the current recommended treatment for donor human milk. Although this method inactivates microbial contaminants, it also negatively affects various milk components. High-pressure processing (HPP, 400, 500, and 600 MPa), ultraviolet-C irradiation (UV-C, 2,430, 3,645, and 4,863 J/L) and thermoultrasonication (TUS, 1,080 and 1,620 kJ/L) were investigated as alternatives to thermal pasteurization (HoP). We assessed the effects of these methods on microbiological safety, and on concentration and functionality of immunoglobulin A, lactoferrin, lysozyme and bile salt-stimulated lipase, with LC-MS/MS-based proteomics and activity assays. HoP, HPP, TUS, and UV-C at 4863 J/L, achieved >5-log10 microbial reduction. Native protein levels and functionality showed the highest reduction following HoP, while no significant reduction was found after less intense HPP and all UV-C treatments. Immunoglobulin A, lactoferrin, and lysozyme contents were also preserved after low intensity TUS, but bile salt-stimulated lipase activity was significantly reduced. This study demonstrated that HPP and UV-C may be considered as suitable alternatives to HoP, since they were able to ensure sufficient microbial inactivation while at the same time better preserving the bioactive components of donor human milk. In summary, our results provide valuable insights regarding the evaluation and selection of suitable processing methods for donor human milk treatment, which may replace HoP in the future.

The efficacy and safety of high-pressure processing of food

High-pressure processing (HPP) is a non-thermal treatment in which, for microbial inactivation, foods are subjected to isostatic pressures (P) of 400-600 MPa with common holding times (t) from 1.5 to 6 min. The main factors that influence the efficacy (log10 reduction of vegetative microorganisms) of HPP when applied to foodstuffs are intrinsic (e.g. water activity and pH), extrinsic (P and t) and microorganism-related (type, taxonomic unit, strain and physiological state). It was concluded that HPP of food will not present any additional microbial or chemical food safety concerns when compared to other routinely applied treatments (e.g. pasteurisation). Pathogen reductions in milk/colostrum caused by the current HPP conditions applied by the industry are lower than those achieved by the legal requirements for thermal pasteurisation. However, HPP minimum requirements (P/t combinations) could be identified to achieve specific log10 reductions of relevant hazards based on performance criteria (PC) proposed by international standard agencies (5-8 log10 reductions). The most stringent HPP conditions used industrially (600 MPa, 6 min) would achieve the above-mentioned PC, except for Staphylococcus aureus. Alkaline phosphatase (ALP), the endogenous milk enzyme that is widely used to verify adequate thermal pasteurisation of cows' milk, is relatively pressure resistant and its use would be limited to that of an overprocessing indicator. Current data are not robust enough to support the proposal of an appropriate indicator to verify the efficacy of HPP under the current HPP conditions applied by the industry. Minimum HPP requirements to reduce Listeria monocytogenes levels by specific log10 reductions could be identified when HPP is applied to ready-to-eat (RTE) cooked meat products, but not for other types of RTE foods. These identified minimum requirements would result in the inactivation of other relevant pathogens (Salmonella and Escherichia coli) in these RTE foods to a similar or higher extent.

Bacillus cereus as a Major Cause of Discarded Pasteurized Human Banked Milk: A Single Human Milk Bank Experience

A systematic study, performed from 2017–2020 looked at the rate of positive post-pasteurization B. cereus findings, the quantity of B. cereus in pasteurized banked human milk (PBM), and the rate of B. cereus toxicogenic isolates from PBM. During the study period, 6815.71 L (30,943 tested bottles) of PBM were tested, with an average amount per year of 1703.93 L (7736 tested bottles). The PBM discard rate per year due to bacterial contamination varied between 8.7–10.0% and contamination with B. cereus was the most frequent reason. The total number of B. cereus positive tests was 2739 and the proportion of its positivity from all positive tests was between 56.7–66.6%. The prevalence of B. cereus positive tests rose significantly in the summer months. The production of enterotoxin was found in 3 of the 20 tested samples (15.0%). The B. cereus CFU-quantities in the PBM were below 10 CFU/mL in 80% of cases (16 of 20 samples tested). The quantitative data can be used in the risk assessment of cold storage of PBM at temperatures above zero and manipulation of PBM prior to its administration.

Applications of novel processing technologies to enhance the safety and bioactivity of milk

Bioactive compounds in food can have high impacts on human health, such as antioxidant, antithrombotic, antitumor, and anti-inflammatory activities. However, many of them are sensitive to thermal treatments incurred during processing, which can reduce their availability and activity. Milk, including ovine, caprine, bovine, and human is a rich source of bioactive compounds, including immunoglobulins, vitamins, and amino acids. However, processing by various novel thermal and non-thermal technologies has different levels of impacts on these compounds, according to the studies reported in the literature, predominantly in the last 10 years. The reported effect of these technologies either covers microbial inactivation or the bioactive composition; however, there is a lack of comprehensive compilation of studies that compare the effect of these technologies on bioactive compounds in milk (especially, caprine and ovine) to microbial inactivation at similar settings. This research gap makes it challenging to conclude on the specific processing parameters that could be optimized to achieve targets of microbial safety and nutritional quality at the same time. This review covers the effect of a wide range of thermal and non-thermal processing technologies including high-pressure processing, pressure-assisted thermal sterilization, pulsed-electric field treatment, cold plasma, microwave-assisted thermal sterilization, ultra-high-pressure homogenization, ultrasonication, irradiation on the bioactive compounds as well as on microbial inactivation in milk. Although a combination of more than one technology could improve the reduction of bacterial contaminants to meet the required food safety standards and retain bioactive compounds, there is still scope for research on these hurdle approaches to simultaneously achieve food safety and bioactivity targets.

Revisiting Non-Thermal Food Processing and Preservation Methods-Action Mechanisms, Pros and Cons: A Technological Update (2016-2021)

The push for non-thermal food processing methods has emerged due to the challenges associated with thermal food processing methods, for instance, high operational costs and alteration of food nutrient components. Non-thermal food processing involves methods where the food materials receive microbiological inactivation without or with little direct application of heat. Besides being well established in scientific literature, research into non-thermal food processing technologies are constantly on the rise as applied to a wide range of food products. Due to such remarkable progress by scientists and researchers, there is need for continuous synthesis of relevant scientific literature for the benefit of all actors in the agro-food value chain, most importantly the food processors, and to supplement existing information. This review, therefore, aimed to provide a technological update on some selected non-thermal food processing methods specifically focused on their operational mechanisms, their effectiveness in preserving various kinds of foods, as revealed by their pros (merits) and cons (demerits). Specifically, pulsed electric field, pulsed light, ultraviolet radiation, high-pressure processing, non-thermal (cold) plasma, ozone treatment, ionizing radiation, and ultrasound were considered. What defines these techniques, their ability to exhibit limited changes in the sensory attributes of food, retain the food nutrient contents, ensure food safety, extend shelf-life, and being eco-friendly were highlighted. Rationalizing the process mechanisms about these specific non-thermal technologies alongside consumer education can help raise awareness prior to any design considerations, improvement of cost-effectiveness, and scaling-up their capacity for industrial-level applications.

High Hydrostatic Pressure Treatment Ensures the Microbiological Safety of Human Milk Including Bacillus cereus and Preservation of Bioactive Proteins Including Lipase and Immuno-Proteins: A Narrative Review

Breast milk is the nutritional reference for the child and especially for the preterm infant. Breast milk is better than donated breast milk (DHM), but if breast milk is not available, DHM is distributed by the Human Milk Bank (HMB). Raw Human Milk is better than HMB milk, but it may contain dangerous germs, so it is usually milk pasteurized by a Holder treatment (62.5 °C 30 min). However, Holder does not destroy all germs, and in particular, in 7% to 14%, the spores of Bacillus cereus are found, and it also destroys the microbiota, lipase BSSL and immune proteins. Another technique, High-Temperature Short Time (HTST 72 °C, 5–15 s), has been tried, which is imperfect, does not destroy Bacillus cereus, but degrades the lipase and partially the immune proteins. Therefore, techniques that do not treat by temperature have been proposed. For more than 25 years, high hydrostatic pressure has been tried with pressures from 100 to 800 MPa. Pressures above 400 MPa can alter the immune proteins without destroying the Bacillus cereus. We propose a High Hydrostatic Pressure (HHP) with four pressure cycles ranging from 50–150 MPa to promote Bacillus cereus germination and a 350 MPa Pressure that destroys 10⁶ Bacillus cereus and retains 80–100% of lipase, lysozyme, lactoferrin and 64% of IgAs. Other HHP techniques are being tested. We propose a literature review of these techniques.

Non-thermal Technologies for Food Processing

Food is subjected to various thermal treatments during processes to enhance its shelf-life. But these thermal treatments may result in deterioration of the nutritional and sensory qualities of food. With the change in the lifestyle of people around the globe, their food needs have changed as well. Today's consumer demand is for clean and safe food without compromising the nutritional and sensory qualities of food. This directed the attention of food professionals toward the development of non-thermal technologies that are green, safe, and environment-friendly. In non-thermal processing, food is processed at near room temperature, so there is no damage to food because heat-sensitive nutritious materials are intact in the food, contrary to thermal processing of food. These non-thermal technologies can be utilized for treating all kinds of food like fruits, vegetables, pulses, spices, meat, fish, etc. Non-thermal technologies have emerged largely in the last few decades in food sector.

Aspects of high hydrostatic pressure food processing: Perspectives on technology and food safety

The last two decades saw a steady increase of high hydrostatic pressure (HHP) used for treatment of foods. Although the science of biomaterials exposed to high pressure started more than a century ago, there still seem to be a number of unanswered questions regarding safety of foods processed using HHP. This review gives an overview on historical development and fundamental aspects of HHP, as well as on potential risks associated with HHP food applications based on available literature. Beside the combination of pressure and temperature, as major factors impacting inactivation of vegetative bacterial cells, bacterial endospores, viruses, and parasites, factors, such as food matrix, water content, presence of dissolved substances, and pH value, also have significant influence on their inactivation by pressure. As a result, pressure treatment of foods should be considered for specific food groups and in accordance with their specific chemical and physical properties. The pressure necessary for inactivation of viruses is in many instances slightly lower than that for vegetative bacterial cells; however, data for food relevant human virus types are missing due to the lack of methods for determining their infectivity. Parasites can be inactivated by comparatively lower pressure than vegetative bacterial cells. The degrees to which chemical reactions progress under pressure treatments are different to those of conventional thermal processes, for example, HHP leads to lower amounts of acrylamide and furan. Additionally, the formation of new unknown or unexpected substances has not yet been observed. To date, no safety-relevant chemical changes have been described for foods treated by HHP. Based on existing sensitization to non-HHP-treated food, the allergenic potential of HHP-treated food is more likely to be equivalent to untreated food. Initial findings on changes in packaging materials under HHP have not yet been adequately supported by scientific data.

Immunological components and antioxidant activity in human milk processed by different high pressure-thermal treatments at low initial temperature and flash holding times

The effect of high pressure thermal (HPT) processing on the immunoglobulin (IgM, IgA and IgG), and cytokine content (IL-6, IL-8, IL-10, and TNF-α), and antioxidant activity of human milk was analyzed after the application of different treatments between 200, and 800 MPa at low initial temperatures (between -15, and 50 °C) and for 1 s (flash treatments). Low pressures intensities did not induce changes in Igs while at 800 MPa, all combinations reduced the control levels. IL-6 and IL-10 were not affected by any of the treatments applied while IL-8 and TNF-α were reduced at treatments which combined temperatures at 50 °C. In general antioxidant activity was not affected at the processing conditions chosen. The flash HPT treatment applied at 600 MPa and at 0 °C could be the best choice to preserve immunological parameters and the antioxidant activity of human milk.