High-temperature Short-time Pasteurization Research Articles

Comparative study on microbiological, physicochemical and nutritional properties of whole cow milk by thermal and non-thermal processing technologies

The majority of the bioactive components in milk exhibit sensitivity to heat treatments. This research is the first systematically compare the effects of thermal (low-temperature long time pasteurization, LTLT; high-temperature short time pasteurization, HTST; ultra-high temperature, UHT; microwave-assisted heating; retort sterilization) and non-thermal (ultraviolet-C, UV-C; high hydrostatic pressure processing, HPP; filtered sterilization; high-intensity ultrasound, HIUS) treatments on the physicochemical properties and immune-active serum proteins of whole milk aliquots under the equivalent microbicidal efficacy. LTLT and HTST had little impact on whole milk. HPP at 400 MPa for 5 min was an optimal alternative to pasteurized milk in terms of equivalent microbicidal efficacy, higher nutrient retention (∼6% and 16.2% loss for IgG and lactoferrin) and fewer oxidation products (0.69 nmol/mg protein carbonyls). The serum protein denaturation of 600 MPa HPP-treated milk (79.4% and 31.36% loss for IgG and lactoferrin) was significantly higher than in pasteurized milk, but still lower than in UHT milk (97.16% and 70.85% loss for IgG and lactoferrin). Since photo-oxidation induced by high-dose irradiation was detrimental to the organoleptic properties, relying on UV-C as stand-alone replacement to pasteurization is not advisable. Combined with existing pasteurization methods, UV-C can achieve superior microbial inactivation at mild sterilization temperatures. HIUS, a promising novel tool, should be further optimized regarding the relevant standards to enable it to be used in industrial-scale processing and reproducibility. Compared with traditional thermal treatments, non-thermal strategies offer a significant reduction in the microbial load of raw milk while better preserving bioactive proteins, However, optimizing processing parameters remains essential to strike a balance between microbial inactivation and retention of active substances.

Characterizing Spoilage of Coconut-based Creamers: A Multifaceted Approach to Identify Problematic Bacteria and Their Potential Sources in a New Product Catego

Beverage innovation is a growing trend with a reliance on comanufacturing relationships to launch products quickly. A recent comanufacturing relationship is the utilization of dairy processing facilities to process plant-based beverages using high-temperature short-time (HTST) pasteurization. While the shelflife of HTST bovine milk is well established at 21 days, retailers are expecting new refrigerated beverages to achieve a 60-day shelflife. Little is known about the microbial stability of these new beverages, particularly those with complex formulations. Our objective was to identify bacterial taxa leading to the spoilage of four coconut-based creamers and their potential sources (raw ingredients or packaging). We used a multifaceted approach including plate counting and 16S rRNA metabarcoding to monitor microbial growth in products throughout shelflife (60 d, 4°C), and cold enrichment (7°C, 11 d) of ingredients and packaging. Nearly, all product units (25/26) had elevated microbial loads (>4.3 log CFU/mL) prior to the 60-d target, with early spoilage detected at 21 d. Key spoilage taxa included Pseudomonas, Streptococcus, Aerococcus, Paenibacillus, Sphingomonas, and Oceanobacillus. Pseudomonas were responsible for “early” product spoilage (21–32 d), whereas Oceanobacillus were important in products with very “late” spoilage (60–62 d). All key spoilage taxa were identified in cold enrichments of multiple units of waxboard cartons. Paenibacillus was the dominant bacterium in 47% (10/21) of product units. In addition to carton samples, Paenibacillus was also identified in one raw ingredient (mushroom extract). Metabarcoding identified Listeria sensu stricto as a dominant taxon in three individual product units from three distinct production lots. Listeria was also found in 31% (5/16) of cold enrichments of individual cartons. Taxa responsible for spoilage of plant-based beverages were identified as well as demonstrating packaging as an important contamination source.

Effects of milk extracellular vesicles from bovine, human, and caprine origin on rotavirus infectivity in cultured human intestinal cells

Rotavirus is the leading cause of severe gastroenteritis in neonates representing a global health burden. Milk-derived extracellular vesicles [EVs] have emerged as potential antivirals, offering a promising avenue for intervention. The present study evaluated the antiviral activity of EVs sourced from bovine, human, and caprine milk against the infection of the human Wa and bovine WC3 rotavirus strains. EVs induced an endogenous effect in Caco-2 cells, resulting in a significant reduction of rotaviral infection. The antiviral properties of the milk EVs, were found to be associated with synergistic interactions at pre- and post-attachment stages of the infection. Finally, the effect of milk processing on bovine milk EVs efficacy was assessed. It was found that after high-temperature short-time pasteurization EVs retained their activity, while homogenization resulted in no antiviral effect at all. Overall, our findings demonstrate a significant reduction in rotavirus infection in cultured Caco-2 cells when treated with milk EVs.

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.

High hydrostatic pressure combined with high-temperature short time pasteurization improves the quality characteristics and extends the shelf life of donkey milk

The processing method, which affects the quality and shelf life of dairy products, depends on the processing stability of raw milk. The effects of high-temperature short time pasteurization (HTST) at 75 °C/15 s and HTST plus high hydrostatic pressure (HHP) at 200, 300 and 400 MPa on the physical stability, soluble calcium and phosphorus concentrations, protein conformation and contents, and storage properties including microbiological characteristics, pH and sedimentation rate of donkey milk were investigated. HTST increased the particle size and lowered soluble calcium and phosphorus concentrations of donkey milk (P < 0.05). HTST plus HPP treatment at 200–400 MPa further increased the particle size and random coil, but decreased β-sheet and β-turn contents with the increasing pressure (P < 0.05). However, HTST plus HPP treatment at 400 MPa reduced the stability of the donkey milk. Moreover, HTST plus HPP treatment at 200–300 MPa preserved lysozyme, α-lactalbumin and β-lactoglobulin (P < 0.05). During the storage period, HTST plus HPP treatment at 300 MPa extended the shelf life by 85.71%, exhibiting stable pH and precipitation rate. It reduced the TMC, coliform and Staphylococcus aureus (P < 0.05). Therefore, our findings suggested HTST at 75 °C for 15 s plus HPP treatment at 300 MPa stabilizes the storage properties of donkey milk while maintaining quality characteristics.

Evaluating the UV-C sensitivity of Coxiella burnetii in skim milk using a bench-scale collimated beam system and comparative thermal sensitivity study by high-temperature short-time pasteurization

Evaluating the UV-C sensitivity of Coxiella burnetii in skim milk using a bench-scale collimated beam system and comparative thermal sensitivity study by high-temperature short-time pasteurization

Microbacterium represents an emerging microorganism of concern in microfiltered extended shelf-life milk products

Growing interest in the manufacture of extended shelf-life (ESL) milk, which is typically achieved by a high temperature treatment called ultra-pasteurization (UP), is driven by distribution challenges, efforts to reduce food waste, and more. Even though high temperature, short time (HTST) pasteurized milk has a substantially shorter shelf-life than UP milk, HTST milk is preferred in the United States because consumers tend to perceive UP milk as less desirable due to the "cooked" flavor associated with high-temperature processing. While ESL beyond 21 d may be possible for HTST, the survival and outgrowth of psychrotolerant aerobic spore-forming bacteria can still be a limitation to extending shelf-life of HTST milk. Microfiltration (MF) is effective for reducing vegetative microorganisms and spores in raw milk, but it is unclear what the effects of membrane pore size, storage temperature, and milk type (i.e., skim vs whole) are on the microbial shelf-life of milk processed by both MF and HTST pasteurization. To investigate these factors, raw skim milk was MF using different pore sizes (0.8 μm or 1.2 μm), and then MF skim milk and standardized whole milk [MF skim with heat-treated (85°C for 20 s) cream] were HTST pasteurized at 75°C for 20 s. Subsequently, milk was stored at 3, 6.5, or 10°C and total bacteria counts were measured for up to 63 d. An ANOVA indicated that mean bacterial concentrations between storage temperatures were significantly different from each other, with mean maximum observed concentrations of 3.67, 5.33, and 8.08 log10 cfu/mL for storage temperatures 3, 6.5, and 10°C, respectively. Additionally, a smaller difference in mean maximum bacterial concentrations throughout shelf-life was identified between pore sizes (<1 log cfu/mL), but no significant difference was attributed to milk type. An unexpected outcome of this study was the identification of Microbacterium as a major contributor to the bacterial population in MF ESL milk. Microbacterium is a psychrotolerant, thermoduric gram-positive, non-spore forming rod with a small cell size (∼0.9 μm length and ∼0.3 μm width), which was able to permeate the membranes used in this study, survive HTST pasteurization, and then grow at refrigeration temperatures. While spores continue to be a key concern for the manufacture of MF, ESL milk, our study demonstrates the importance of other psychrotolerant, thermoduric bacteria such as Microbacterium to these products.

Use of HPLC-MS to Determine the Loss of Metabolites in Apple Juices under Different Storage Conditions.

The focus of this experiment was to compare the color and metabolic profile of apple juice from the red-fleshed cultivar 'Baya Marisa' with the white-fleshed cultivar 'Golden Delicious'. The changes in the phenolic compounds, organic acids, and sugar content during high-temperature short-time pasteurization and after one year of storage under different storage conditions were analyzed. A total of 26 individual phenolic compounds were identified and quantified. The total analyzed phenolics content (TAPC) decreased after pasteurization of the juices of both cultivars. The TAPC of fresh 'Baya Marisa' juice after pasteurization increased or remained the same compared to one-year stored 'Baya Marisa' juice, depending on the storage method. The sucrose content of the apple juice of both cultivars remained the same after pasteurization; interestingly, it decreased significantly after one year of storage, while the fructose and glucose content remained the same after pasteurization and increased significantly after one year of storage for both cultivars.

Effect of Direct Steam Injection and Instantaneous Ultra-High-Temperature (DSI-IUHT) Sterilization on the Physicochemical Quality and Volatile Flavor Components of Milk.

The effects of variations in the heat treatment process of milk on its quality and flavor are inevitable. This study investigated the effect of direct steam injection and instantaneous ultra-high-temperature (DSI-IUHT, 143 °C, 1-2 s) sterilization on the physicochemical properties, whey protein denaturation (WPD) rate, and volatile compounds (VCs) of milk. The experiment compared raw milk as a control with high-temperature short-time (HTST, 75 °C 15 s and 85 °C 15 s) pasteurization and indirect ultra-high-temperature (IND-UHT, 143 °C, 3-4 s) sterilization. The results showed no significant differences (p > 0.05) in physical stability between milk samples with different heat treatments. The DSI-IUHT and IND-UHT milks presented smaller particle sizes (p < 0.05) and more concentrated distributions than the HTST milk. The apparent viscosity of the DSI-IUHT milk was significantly higher than the other samples (p < 0.05) and is consistent with the microrheological results. The WPD of DSI-IUHT milk was 27.52% lower than that of IND-UHT milk. Solid-phase microextraction (SPME) and solvent-assisted flavor evaporation (SAFE) were combined with the WPD rates to analyze the VCs, which were positively correlated with ketones, acids, and esters and negatively associated with alcohols, heterocycles, sulfur, and aldehydes. The DSI-IUHT samples exhibited a higher similarity to raw and HTST milk than the IND-UHT samples. In summary, DSI-IUHT was more successful in preserving the milk's quality due to its milder sterilization conditions compared to IND-UHT. This study provides excellent reference data for the application of DSI-IUHT treatment in milk processing.

Polyphenol Release and Antioxidant Activity of the Encapsulated Antioxidant Crude Extract from Cold Brew Spent Coffee Grounds under Simulated Food Processes and an In Vitro Static Gastrointestinal Model

An ionic gelation technique based on an alginate-calcium-based encapsulation process was prepared as the delivery matrix for antioxidant crude extracts from cold brew spent coffee grounds (350 mg/mL). All the encapsulated samples were treated with different simulated food processes, namely pH 3, pH 7, low-temperature long-time (LTLT) pasteurization, and high-temperature short-time (HTST) pasteurization, to evaluate the stability of the encapsulated matrices. The results showed that alginate (2%, w/v)/maltodextrin (2%, w/v) (CM), and alginate (2%, w/v)/inulin (5%, w/v) (CI) could enhance encapsulation efficiency (89.76 and 85.78%, respectively) and provide lower swelling behavior after being treated using the simulated food processes. Both CM and CI could control the release of antioxidants during the gastric phase (2.28-3.98 and 2.52-4.00%, respectively) and gradual release in the intestinal phase (6.80-11.78 and 4.16-12.72%, respectively) compared to pure alginate (CA). In addition, pasteurization treatment at pH 7.0 produced the highest accumulated release of total phenolic content (TPC) and antioxidant activity (DPPH) after digestion in the in vitro gastrointestinal system compared to the other simulated food processes. The thermal process resulted in a greater release of compounds from the encapsulated matrix during the gastric phase. On the other hand, the treatment with pH 3.0 resulted in the lowest accumulated release of TPC and DPPH (5.08 and 5.12%, respectively), which indicated phytochemical protection.

Processors' understanding of process quality: a qualitative interview study with employees of organic dairies in Germany and Switzerland

PurposeOrganic food processing must include organic principles to be authentic. This qualitative study aims to understand the processors' understanding of organic food processing quality.Design/methodology/approachThis study is based on semi-structured expert interviews with eight employees of six purely or partly organic dairies from Germany and Switzerland. Interview themes are (1) quality of organic milk processing in general, (2) assessment of specific processing techniques, (3) product quality of organic milk and (4) flow of information between producer and consumer. The interviews have been audio-recorded, transcribed verbatim and thematically analysed.Findings(1) Experts prefer minimal processing; some prefer artisanal processing, whilst others stress the advantages of mechanisation. (2) High temperature short time (HTST) pasteurisation and mechanical processing techniques are accepted; ultra-high-temperature (UHT) milk processing is partly rejected. (3) Traditional taste and valuable ingredients should be present in the final product. Natural variances are judged positively. (4) Consumers' low level of food technology literacy is challenging for communication.Research limitations/implicationsThe results cannot be generalised due to the qualitative study design. Further studies, e.g. qualitative case analyses and studies with a quantitative design, are necessary to deepen the results.Practical implicationsThe paper shows which processing technologies experts consider suitable or unsuitable for organic milk. The paper also identifies opportunities to bridge the perceived gap between processors' and consumers' demands.Originality/valueThe study shows the challenges of processors in expressing the processors' understanding of process quality.

Thermosonication as a pretreatment of raw milk for Minas frescal cheese production

Minas frescal cheese is extremely popular in Brazil, with high perishability and acceptability. Among emerging technologies, ultrasound stands out for its satisfactory results regarding microbiological safety and technological and sensory aspects. The combined mild temperature application, called thermosonication, can generate even more promising results. In this study, a high-intensity ultrasound system combined with thermal heating (TS, thermosonication) was applied for the treatment of raw milk to produce Minas Frescal cheese. US energy was delivered to raw milk samples using a probe operating at a 20kHz of frequency and nominal power of 160, 400, and 640W. The TS system was compared with conventional pasteurization (HTST, high-temperature short-time pasteurization) at 72 to 75°C and 15s. Soft cheeses were prepared with different samples: (a) raw milk (control), b)conventionally pasteurized milk (HTST), and c) TS treat milk in different nominal power (TS160, TS400, and TS640). The produced cheeses were evaluated for microbiological behavior, rheology, color parameters, and bioactive compounds. TS treatment in milk resulted in higher microbial inactivation and stability during storage, improved color parameters (higher lightness (L*), and whiteness index (WI). TS treatment also showed a higher generation of bioactive compounds (higher antioxidant, and inhibitory activities of α-amylase, α-glucosidase, and angiotensin-converting enzymes) than HTST. The impact of TS on rheological properties was similar to HTST, resulting in more brittle and less firm products than the cheese produced with raw milk. The positive effects were more prominent using a nominal power of 400W (TS400). Therefore, TS proved to be a promising process for processing milk for Minas Frescal cheese production.

A novel heat treatment protocol for human milk.

Human milk (HM) is the recommended nutrition for premature infants, but it may require processing to ensure microbial safety. The current standard is Holder pasteurisation (HoP), i.e. heating milk at 62.5 ± 0.5°C for 30 min, which eliminates bacteria but destroys heat labile bioactive HM components. We aimed to test an alternative thermal method, high-temperature short-time (HTST) pasteurisation using a modified Holder pasteurisation platform as this method has shown to preserve proteins in experimental HM flow pasteurisers. We analysed the ability of this batch process to eliminate bacterial species and to retain alkaline phosphatase, secretory immunoglobulin A and lactoferrin in HM. HTST at 81°C/5 s was as effective as HoP in bacterial count reduction while the retention of bioactive components was only improved at 62°C/5 s as compared to 72°C/5 s and HoP. HTST is a promising alternative to HoP but an optimal temperature-time combination needs to be determined for each technical platform separately.

Lactobacillus rhamnosus GR-1 attenuates foodborne Bacillus cereus-induced NLRP3 inflammasome activity in bovine mammary epithelial cells by protecting intercellular tight junctions

BackgroundBacillus cereus is an important pathogen that causes human food poisoning, specifically diarrhea and vomiting. B. cereus can also induce mastitis in dairy cows and has a strong survival ability in milk, as it cannot be inactivated by high-temperature short-time pasteurization. Therefore, B. cereus can enter the market through pasteurized milk and other dairy products, imposing enormous hidden dangers on food safety and human health.ResultsIn this study, B. cereus 2101 (BC) was isolated from milk samples of cows with mastitis. BC grew rapidly with strong hemolysis, making it difficult to prevent mastitis and ensure food security. MAC-T cells were treated with BC and/or Lactobacillus rhamnosus GR-1 (LGR-1). Pretreatment with LGR-1 protected the integrity of tight junctions and the expression of zonula occludens-1 (ZO-1) and occludin destroyed by BC. Furthermore, LGR-1 pretreatment reduced the expression of NOD-like receptor family member pyrin domain-containing protein 3 (NLRP3), caspase recruitment and activation domain (ASC), Caspase-1 p20, gasdermin D (GSDMD) p30, inflammatory factors (interleukin (IL)-1β and IL-18), and cell death induced by BC. Moreover, LGR-1 pretreatment reduced NLRP3 inflammasome activity and increased expressions of ZO-1 and occludin induced by lipopolysaccharides (LPS) + ATP stimulation. MAC-T cells were transfected with NLRP3 siRNA or MCC950 and/or treated with BC and/or LGR-1. NLRP3-siRNA transfection and MCC950 attenuated BC-induced NLRP3 inflammasome activity. Expression of inflammatory cytokines and cell death suggested that the inflammatory pathway might play an important role in the induction of the NLRP3 inflammasome by BC and the protection of LGR-1.ConclusionsThese results suggest that LGR-1 might be a probiotic alternative to antibiotics and could be administered to prevent mastitis in dairy cows, thus ensuring food security.

Improving the microbial and nutritional quality of skim milk using microfiltration combined with thermal and nonthermal techniques

The effectiveness of microfiltration (MF), alone or combined with high temperature short time (HTST) pasteurisation, ultraviolet-C (UV-C), and ultrasonication (US) in improving the microbial and nutritional quality of skim milk was evaluated in comparison with commercial ultra-pasteurisation (UP). Compared with untreated skim milk, MF combined with UV-C and US retained more bioactive proteins, which made these techniques superior to MF combined with HTST. Almost no bioactive proteins survived after UP. MF alone reduced the bacterial load by 2.5 log; however, MF combined with HTST (MH), UV-C (MUV), or US (MUS) can reduce the bacterial load to an undetectable level and extend the microbial shelf-life of skim milk to 40 days. In addition, MUV and MUS did not induce significant protein oxidation. Even though the skim milk after MUV or MUS showed only minor microbial growth, the shelf-life was limited by proteolysis through plasmin activity.

Inactivation Kinetics of Coxiella burnetii During High-Temperature Short-Time Pasteurization of Milk.

The Gram-negative, obligate intracellular bacterium Coxiella burnetii is the causative organism of the zoonosis Q fever and is known for its resistance toward various intra- and extracellular stressors. Infected ruminants such as cattle, sheep, and goats can shed the pathogen in their milk. Pasteurization of raw milk was introduced for the inactivation of C. burnetii and other milk-borne pathogens. Legal regulations for the pasteurization of milk are mostly based on recommendations of the Codex Alimentarius. As described there, C. burnetii is considered as the most heat-resistant non-spore-forming bacterial pathogen in milk and has to be reduced by at least 5 log10-steps during the pasteurization process. However, the corresponding inactivation data for C. burnetii originate from experiments performed more than 60 years ago. Recent scientific findings and the technological progress of modern pasteurization equipment indicate that C. burnetii is potentially more effectively inactivated during pasteurization than demanded in the Codex Alimentarius. In the present study, ultra-high heat-treated milk was inoculated with different C. burnetii field isolates and subsequently heat-treated in a pilot-plant pasteurizer. Kinetic inactivation data in terms of D- and z-values were determined and used for the calculation of heat-dependent log reduction. With regard to the mandatory 5 log10-step reduction of the pathogen, the efficacy of the established heat treatment regime was confirmed, and, in addition, a reduction of the pasteurization temperature seems feasible.

Rheological properties of fermented milk from heated and high pressure-treated camel milk and bovine milk

Gelation of camel milk is a challenge to the industrial utilization. This study investigated the impact of low-temperature long-time (LTLT) and high-temperature short-time (HTST) pasteurization, ultra-high temperature (UHT) treatment, and high-pressure processing (HPP), at 300 and 600 MPa, on the rheological properties of the fermented milk. Both camel and bovine milk were fermented by Lactiplantibacillus plantarum and Ligilactobacillus salivarius. Both milk treated at 300 and 600 MPa showed the highest Lb. plantarum and Lb. salivarius numbers, with ∼9 log.HTST and UHT-treatment increased particle size in bovine milk but decreased it in camel milk. HPP-treatment decreased particle size in both camel and bovine milk. All fermented milk showed shear-thinning behavior, regardless of milk type, processing, culture type and storage time. For both camel and bovine milk, fermented UHT-treated milk had the highest viscosity followed by fermented HPP-treated milk. Lowest viscosities were observed for fermented LTLT-treated and HTST-treated milk. Small deformation rheology showed consistently lower tan δ values for fermented HPP-treated camel milk than for fermented heated camel milk, with the latter only giving tan δ < 1 at elevated frequencies. UHT- and HPP-treatment of milk can enhance the rheological properties of fermented camel milk compared with other heat treatments.

Treated Cow Milk Quality Analysis in High-Temperature Short Time (HTST) Thermal Treatment using F-Value and Methylene Blue Reduction Test (MBRT)

This study was conducted to evaluate raw and pasteurized cow milk regarding physical properties, microbiological quality, and lethality value ofMycobacterium Paratuberculosis(MAP)at different temperature and time combinations of the pasteurization process.Cow milk samples were pasteurized at high-temperature (70°C, 75°C, and 81°C) and short-time (15s and 25s) high temperature and short time (HTST) combinations. Raw and pasteurized (HTST) cow milk was analyzed, while commercial cow milk that undergo proses (HTST) was used as control. High-temperature short time (HTST) pasteurization showed a significant effect on the colour of raw and pasteurized cow milk (p&lt;0.05) at every temperature. In addition, cow milk also indicated an increase in lightness and yellowness after HTST pasteurization.The microbiological quality of raw, pasteurized, and commercial cow milk is evaluated using the Methylene Blue Reduction (MBRT) test, a common, rapid, simple, and inexpensive method for microbiological quality evaluation.The MBRT on raw milk samples revealed that it was of poor quality. On the other hand, all pasteurized samples were good quality, and the commercial sample was excellent.Based on the evaluated F-values, the most suitable temperature and time combinationsin this study was 70°C and 25s.

Simulated dynamic digestion reveals different peptide releases from human milk processed by means of holder or high temperature-short time pasteurization

High Temperature-Short Time (HTST) pasteurization was proposed as an alternative to Holder pasteurization (HOP) to increase the retention of specific human milk (HM) bioactive proteins. The present study explored whether HTST and HOP differently affect peptide release during simulated preterm infant gastrointestinal digestion. Raw (RHM), HOP- and HTST- pasteurized HM were digested using an in vitro dynamic system, and the identified peptides were analyzed by mass spectrometry and multivariate statistics. Before digestion, 158 peptides were identified in either RHM, HTST- or HOP- HM, mostly (84.4%) originating from β-casein (CASB). During gastric digestion, HOP-HM presented a greater number and more abundant specific CASB peptides. A delayed release of peptides was observed in RHM during the intestinal phase, with respect to both pasteurized HM. Although limited to gastric digestion, the HM peptidomic profile differed according to the pasteurization type, and the pattern of the HTST peptides showed a greater similarity with RHM.

Effects of pasteurization, microfiltration, and ultraviolet-c treatments on microorganisms and bioactive proteins in bovine skim milk

Effects of high-temperature short-time (HTST) pasteurization, microfiltration (MF) with 1.4/0.8 μm pore diameters, and ultraviolet-c (UV-C) irradiation with a coiled tube reactor on reducing microorganisms and somatic cells, and retaining bioactive proteins/enzymes along with protein oxidation in skim milk were studied. Bacteria were reduced by 2.3 log using HTST and UV-C, and 3.0 log using MF. Coliforms were not detected after all treatments. Spores were unaffected by HTST, reduced by 0.3 log using UV-C, and not detected after MF. Somatic cells remained unaffected by HTST and UV-C, and were undetectable after MF. Bioactive xanthine oxidase (XO), immunoglobulin G (IgG), lactoperoxidase (LPO), lactoferrin (LF), IgM, and IgA were retained at 87, 78, 69, 57, 48, and 41% using HTST, and 100% using UV-C and MF-1.4, while MF-0.8 retained fully the IgG and LPO, and 93, 92, 91, and 86% of IgA, XO, LF, and IgM. Native serum proteins were retained at 89% using HTST, 95% using UV-C, and 100% using MF. Carbonyls were increased by 26% using UV-C, and sulfhydryls were reduced by 14% using HTST, while both were unaffected using MF. Flux for MF-1.4 was higher and remained steady after an initial decrease of 12%, while flux for MF-0.8 decreased progressively by 45% until end of processing, resulting in complete and 89% passages of casein micelles using MF-1.4 and MF-0.8. MF-1.4 and UV-C could be proposed as nonthermal technologies alternatives or as hurdle-technologies to HTST for reducing microorganisms while retaining bioactive proteins/enzymes in skim milk, without inducing significant oxidative effects.