Pasteurization Temperature Research Articles

Effect of Pasteurization and Storage Temperatures on the Quality of Carrot Juices

Effect of Pasteurization and Storage Temperatures on the Quality of Carrot Juices

Protein Stability in Pasteurized Cow and Goat Milk using Protein Gel Electrophoresis

Milk is a nutritious beverage that contains whey, casein, and milk fat globule membrane (MFGM) proteins. Pasteurization kills pathogenic microorganisms in milk, making it safe to drink. A high heat load during processing can affect the protein quality of milk. In this study, protein gel electrophoresis (Native and SDS-PAGE) was used to view the protein profiles of retail cow and goat milk samples pasteurized at different temperatures (145, 165, or 280 °F) compared to commercially spray dried milk (356–482 °F). SDS-PAGE provided better resolution of the milk proteins compared to Native-PAGE. There were clear species differences in the MFGM proteins. This could be used to spot adulteration of goat milk with cow milk, however none of the samples showed signs of adulteration. There were no overt patterns of protein degradation with increasing pasteurization temperature. However drying reduced band intensity, especially MFGM and whey proteins in the goat milk sample. Whereas most samples came from different herds where genetics and environmental conditions varied, two of the goat milk samples were from the same herd, one fresh and one spray dried. It was evident from these two samples that spray drying can alter proteins in goat milk. Even so, if fresh milk is unavailable or unaffordable, dry milk remains a valuable protein source.

Lighter as flame control and temperature control in milk pasteurization system

Milk pasteurization involves heating milk at a specific temperature below its boiling point as a method to keep the resulting dairy product retaining the shape and taste characteristics of fresh milk. In several experiments, the use of fuzzy control systems has been tested to regulate the temperature in the milk pasteurization process and to time the ignition of the stove flame. However, this fuzzy approach still causes the system to give an unstable response and irregular stove flame. In order to study milk pasteurization, the Low Temperature Long Time (LTLT) method is used which is implemented automatically through a PID control system. This method serves to maintain nutritional quality by keeping the pasteurization temperature at a setpoint of 62°C. This control involves the use of servo actuators and electric lighters that are automatically regulated with the help of flame sensors. The flame sensor detects the presence of flame and ensures that the flame remains lit throughout the pasteurization process. At the end of the process, the flame sensor plays a role in breaking the flame by setting a certain threshold. This sensor operates within 10 CM of the flame source and will produce an analog output with a maximum value of 4000 when the flame is lit. When the flame is extinguished, the analog output of the sensor will reach a value of 4095. Testing of the milk pasteurization automation system is given a value for each PID resulting from the value of Kp = 31.8, Ki = 115.6, Kd = 4.4 and obtained a rise time value of 0.39 minutes, 0.61%, settling min of 60.88, and settling max of 62.38.

Mathematical modeling and optimization of pasteurization for the internal pressure and physical quality of canned beer

Globally, beer is the most popular alcoholic beverage. To accomplish microbial stabilization and extend the shelf life of beer, it is typically subjected to in-package pasteurization using a tunnel pasteurizer. However, high internal pressure can cause can bulging during pasteurization, leading to significant product loss. In this study, an empirical mathematical model was constructed to describe the effects of can thickness (0.245–0.270 mm), fill volume (320–338 mL), carbon dioxide content (5.70–6.10 g/L), and pasteurization temperature (59–66 °C) on the internal pressure inside canned beer. A laboratory-scale pasteurization setup was used to pasteurize samples based on the worst-case scenario of commercial pasteurization. The mathematical model (R2 = 0.90) showed that all parameters significantly influenced the internal pressure of pasteurized canned beer (p < 0.05). Additionally, the physical, chemical, and biological properties of pasteurized canned beer were assessed. All values fell within an acceptable range of industrial standards. A simplified 2nd-order polynomial equation (R2 = 0.90) was created and verified for industrial use. The data are well represented by the simplified model, which suggests that it could be used for optimization of product- and process parameters to reduce the occurrence of can bulging in commercial pasteurization of canned beer.

Implications of Pulsed Electric Field Pre-Treatment on Goat Milk Pasteurization.

Goat milk is an interesting product from a nutritional and health standpoint, although its physico-chemical composition presents some technological challenges, mainly for being less stable than cow's milk at high temperatures. As pasteurization and ultra-high temperature processing are universally employed to ensure milk quality and safety, non-thermal methods, such as pulsed electric fields (PEFs), reduce the microbial load and eliminate pathogens, representing an interesting alternative for processing this product. This study demonstrates how the combined use of a PEF with short thermal processing and moderate temperature can be effective and energy-efficient in goat milk processing. A combination of thermal treatment at 63 °C after a low-intensity PEF (50 µs pulses, 3 Hz, and 10 kV·cm-1) caused the same reduction effect on the population of Listeria monocytogenes (goat's raw milk artificially spiked), as compared to a thermal treatment at 72 °C without a PEF. However, z values are significantly higher when PEF is used as a pre-treatment, suggesting that it may induce heat resistance in the survival population of L. monocytogenes. The sensitivity of L. monocytogenes to high temperatures is less pronounced in goat's milk than cow's milk, with a more pronounced impact of a PEF on lethality when combined with lower temperatures in goat's milk. The effect of a PEF on Escherichia coli viability was even more pronounced. It was also observed that thermal treatment energy needs with a PEF as a pre-treatment can be reduced by at least 50% of the total energy requirements.

Effects of ultra-high pressure, thermal pasteurization, and ultra-high temperature sterilization on color and nutritional components of freshly-squeezed lettuce juice

The aim of this study was to evaluate the effects of ultra-high pressure (UHP, 600 MPa/2 min), thermal pasteurization (TP, 95 °C/1 min) and ultra-high temperature (UHT, 115 °C/5 s) sterilization on the color, sensory evaluation, microorganisms, physicochemical characteristics and nutritional components of freshly-squeezed lettuce juice (FLJ). Results showed that three sterilization methods demonstrated desirable inactivation effects on total aerobic bacteria, yeast and mold, and there were no significant changes in the main nutritional components, including ash, protein, carbohydrate and total dietary fiber. However, UHT and TP significantly affected the color of FLJ from bright green to light brown and made chlorophyll, β-carotene and vitamins (VE, VC, VK1, VB6, VB12, and folic acid) contents markedly decreased. By contrast, UHP maintained the original color, fresh-like sensory qualities, vitamins, and carotene of FLJ to the greatest extent. Our results provide a promising application of UHP in the large-scale processing of FLJ.

Enhancement of foaming properties and storage stability of pasteurized liquid egg white through ultrasound modification

Due to the high heat sensitivity of liquid egg white (LEW), there were a loss of foaming properties during pasteurization. At the same time, the temperature of pasteurization was limited by this property and did not limit the growth of microorganisms very well. Therefore, the article hoped to improve the foaming characteristics of pasteurized liquid egg white (PLEW) and to increase the stability during storage by using water-bath ultrasound. It was found that the foaming capacity of the pasteurization only group increased from 270% to 326% under optimal sonication conditions (60 Hz, 400 W, 15 min). The increase in protein solubility and decrease in particle size following ultrasound suggested that ultrasound had a deaggregation effect. The fact that surface tension was reduced suggested that sonication could provide more soluble proteins and a more flexible conformation for PLEW. Both free sulfhydryl and surface hydrophobicity were enhanced, which might be related to the disruption of protein molecular forces by the cavitation effect of ultrasound. The results of spectral analysis again revealed that the essence of ultrasound to improve the foaming properties of PLEW lied in changing the conformation of the protein molecule. Furthermore, the results also demonstrated that the ultrasound-treated LEW showed better foaming properties, minimal changes in viscosity, lower total volatile basic nitrogen content, and a longer shelf life (40 d) during storage. The quality of the ultrasound-treated group remained the most stable. Therefore, ultrasound has great potential for improving the foaming ability and stability of PLEW.

Quality evaluation and shelf life analysis of fruit juice cocktail containing Mango (Mangifera indica) and Pineapple (Ananascomosus)

The development of the innovative flavored juices by coalescing two or more distinct types of fruits is encouraged by the tremendous expansion of the juice industry. Fruit juice cocktails frequently contain high nutritional content as well as organoleptic features such as color, flavor, taste, and overall attractiveness of various fruits. The use of different heat treatments and storage temperatures on single juice has previously been extensively researched, however, only a limited study has been performed on a juice cocktail. Therefore, the effect of pasteurization temperature (60 °C and 90 °C) and storage temperature (4 °C and 25 °C) on physicochemical, microbial, and sensory properties of pineapple-mango juice cocktail was investigated. Standard procedures were used to determine physicochemical, microbiological, and sensory characteristics. The results of the study demonstrated a slight increase in TSS, acidity, and cloud stability during storage, while a gradual decrease in vitamin C, pH, total sugars, and Lovibond color. The S4 sample that was pasteurized at 60 °C for 20 min and maintained at 4°C storage temperature retained more vitamin C, acidity, and total sugar than the other samples. According to the microbiological data, the total viable count in the fruit juice cocktail samples varied from 3.42 × 102 to 8.5 × 107, and after two months of storage, the bacterial load in sample S4 increased from 3.52 × 102 to 5.5 × 103. The sensory evaluations revealed that all of the samples were widely accepted, with sample S4 having the greatest overall acceptance owing to the cocktails color, flavor, and taste. Therefore, this study demonstrates that perishable fruits may be turned into appealing juice cocktails, increasing the sensory characteristics and hence the products escalation value. These findings also promote the development of a healthy and nutritious, fruit-based juice cocktail.

In vitro Survival of Microencapsulated Canine-Specific Probiotics Under Simulated Gastrointestinal Tract Conditions and During Storage

The survival of probiotics in the gastrointestinal system of dogs is crucial for them to provide health benefits. However, probiotics must also endure various physical conditions during commercial production and storage. Therefore, this study employed the microencapsulation technique to ensure the survival of probiotics using alginate as the encapsulation material, both alone and in combination with goat milk (alginate-goat milk). The study assessed the survival rates of two probiotic LAB strains, Enterococcus hirae Pom 4 and Ligilactobacillus animalis FB2, in both types of matrices under simulated dog gastrointestinal conditions, during food production, and 28 days of refrigeration at 4°C. The findings revealed that alginate-goat milk microcapsules had the highest encapsulation yield, and the viability of microencapsulated LAB cells in the alginate-goat milk matrix was the best protection for both probiotic strains under all conditions, including pasteurization temperature. Even after pasteurization, viable counts exceeding 6 log cfu/g were observed, indicating the promising application of alginate-goat milk microcapsules for optimal protection, enabling probiotics to survive until they reach the intended site and provide health benefits to dogs.

Analysis of the Responses to Pasteurization Temperatures of Methicillin Resistant Staphylococcus aureus Derived from Milk Items

Background and Aim: One of the leading causes of both community- and hospital-acquired infections is the superbug," multidrug-resistant Staphylococcus aureus (MRSA). Milk and dairy products seem to be highly vulnerable to a wide range of diseases. Therefore, we require processing procedures that both eliminate pathogens and lengthen the useful life of these products. The purpose of this study was to determine how susceptible MRSA isolates were to pasteurization temperatures after being recovered from dairy products.&#x0D; Materials and Methods: For the purpose of pasteurization, ten MRSA isolates were exposed to both a 63°C LTLT (low temperature, long time) therapy for 30 minutes and a 72°C HTST (high temperature, short time) treatment for 16 seconds.&#x0D; Results: The findings indicated that all isolates were killed by a pasteurization-like treatment at low temperature for a long time (63°C for 30 minutes), but that particular adaptable isolates could survive a pasteurization-like treatment at high temperature for a short time (72°C for 16 seconds), which may point to a time- and temperature-dependent variation in the thermal tolerance mechanism.&#x0D; Conclusion: The results showed that all isolates seemed extremely susceptible to damage from heat using LTLT pasteurization-like treatment (63°C for 30 minutes). Nevertheless, a particular number of these isolates succeeded in establishing colonies because they have quorum sensing structures that survive being handled by using heat damage at 72°C for 16 seconds. Pasteurized milk producers should be alerted to the fact that this microorganism has been found in contaminated milk since it compromises the product's safety and diminishes its value to consumers. As a result, it is strongly advised that manufacturers utilize varied temperatures for milk processing in order to remove the contaminating methicillin- and heat-resistant S. aureus (MHRSA).

The impact of thawing duration on leptin and adiponectin levels in frozen human milk samples.

Measurements of hormone concentrations in human milk from understudied populations across the world is of growing scientific interest. Due to limited access to suitable laboratory facilities at many research sites, human milk samples are often shipped frozen to distant laboratories for analysis. Shipping and handling exposes samples to the risk of thawing and degradation as the results of delays, mishandling, or other unforeseen circumstances. Similar degradation risk factors are well known in serum samples. However, the vulnerability of hormone degradation in human milk to thawing during transportation is largely unexplored. Leptin and adiponectin are of particular importance due to their roles in feeding behavior and metabolism in infants, hence our focus on these two hormones. In addition, leptin and adiponectin have been shown to be vulnerable to pasteurization temperature degradation in human milk samples. We tested the degradation of human milk metabolic hormones - leptin and adiponectin - in a controlled environment in response to a variety of freeze/thaw conditions that are reflective of potential temperature fluctuations during transportation. Human milk samples were experimentally subjected to thaw durations ranging from 4 to 16 h and assayed for hormonal levels to observe changes from baseline. Samples were also subjected to two additional experimental conditions, re-freezing after an extended period outside freezers or remaining thawed with additional ice packs, to investigate the impact of common transportation conditions. We found the assayed levels of leptin were not significantly impacted by an extended thaw cycle of 16 h. However, leptin levels were impacted by the extended period of 40 h outside of the freezer. Adiponectin showed a decrease in concentration percentage after the initial 16-h thaw period, but the increased degradation between 0-16 h and 16-40 h was not as severe as that seen in the leptin samples. The results of this experiment can be used to inform hormone measurement consistency given different thawing lengths or freezing conditions during transportation. Additionally, this research informs decisions regarding transportation, storage/handling, and data analysis in human milk research.

The Microbial Community in a Substrate of Solid-State Fermentation by Lentinula edodes: A Preliminary Study

Edible-fungal-based solid-state fermentation holds promise for sustainable food and biofuel production. Understanding the role of microbial communities in fungal substrates is crucial. Birch-based substrates were treated with autoclaving (121 °C, at 2 bar) or hot air pasteurization (75–100 °C), followed by incubation with and without shiitake (Lentinula edodes) inoculum. Mycelial growth was monitored by CO2 release and microbial biomass by phosphate-lipid fatty acid (PLFA). DNA sequencing was used to analyze the microbial communities. Results showed successful colonization of shiitake on all substrates, regardless of pasteurization temperatures and coexisting microbes. Total microbial respiration (CO2) and PLFA biomass showed no significant differences between pasteurization regimes. However, significant microbial differences were found between shiitake-inoculated and non-inoculated treatments. DNA sequencing revealed the dominance of Phyllobacterium, Sphingomonas, and Pelomonas genera in all inoculated substrates, while non-inoculated substrates were abundant in Bacillus spp. and Paenibacillus spp. of the Firmicutes phylum. This study provides preliminary insights into the microbial community in birch-based shiitake substrates, facilitating further investigation of bacteria involved in shiitake mycelium growth promotion and biochemical conversion for biofuel production.

Validation of Pasteurisation Temperatures for a Tomato-Oil Homogenate (salmorejo) Processed by Radiofrequency or Conventional Continuous Heating.

Salmorejo is a viscous homogenate based on tomato, olive oil and breadcrumbs commercialised as a "fresh-like" pasteurised-chilled purée. Due to its penetration, dielectric heating by radiofrequency (RF) might improve pasteurisation results of conventional heating (CH). The objective was to validate the pasteurisation temperature (70-100 °C, at 5 °C intervals) for salmorejo processed by RF (operating at 27.12 MHz for 9.08 s) or conventional (for 10.9 s) continuous heating. The main heat-induced changes include: orangeness, flavour homogenisation, loss of freshness, thickening, loss of vitamin C and lipid oxidation. Both CH and RF equivalent treatments allowed a strong reduction of total and sporulated mesophilic microorganisms and an adequate inhibition of the pectin methylesterase, peroxidase and, to a lesser extent, polyphenol oxidase but did not inhibit the polygalacturonase enzyme. Pasteurisation at 80 °C provided a good equilibrium in levels of microbiological and enzymatic inhibition and thermal damage to the product. Increasing this temperature does not improve enzyme inactivation levels and salmorejo may become overheated. A "fresh-like" good-quality salmorejo can be obtained using either conventional or radiofrequency pasteurisers.

A new protocol for radio frequency heating of low-moisture, viscous sauces and its temperature uniformity optimisation

AbstractRadio frequency (RF) heating of agri-food, especially low moisture viscous sauces (LMVS), have obvious advantages. However, uneven heating is one main problem of RF heating technology that has to be solved. Due to the unclear heating mechanism and the difficulty to measure the three-dimensional temperature distribution in the heated object, computer-aided analysis method was adopted. Based on the RF heating numerical calculation model after experimental verification and the characteristics of polyetherimide (PEI) assisted RF heating of peanut butter (PB), this study proposed an improved method for an existing protocol. Meanwhile, parameters of the new protocol were optimised by the Multi-objective Global Optimisation (MGO) of its surrogate model. Results demonstrated that the best size of PEI block in the new protocol was Φ100 × 9.5 mm and the positional height was 12 mm. When the pasteurisation temperature Tp was set to 70 °C and the control temperature Tc was set to 75 °C, the temperature uniformity evaluation indices, Over-shoot Temperature Control Index (OTCI) and Targeted Penetration Depth (TPD), were 0.920% and 3.975 mm, respectively. Compared with 4.845% and 4.940 mm before improvement, the new protocol achieved significant optimisation and improved the temperature uniformity effectively. This also proved the feasibility of MGO method of surrogate model in relevant studies.

Pre-pasteurization enhances the fermentation of wheat straw by Irpex lacteus: Chemical composition, enzymatic hydrolysis, and microbial community

Pasteurization is an economical and convenient method to eliminate harmful microorganisms in raw materials for fermentation. However, the surviving species in pasteurized wheat straw and their potential effects on white rot fungi fermentation remain unclear. In this study, wheat straw was pasteurized at different temperatures (60–85 ℃) and fermented with Irpex lacteus for 28 days. At the end of fermentation, the acid-insoluble lignin (ADL) content decreased significantly in all pasteurized samples (P < 0.05). We found a negative correlation between ADL content and pasteurization temperature (R =0.992, P < 0.001). In enzymatic hydrolysis, the sugar yield of samples pasteurized at 80 ℃ (T80) was higher 39.9% than that at 60 ℃. Regarding microbial community, I. lacteus was the dominant fungus in T80 at an abundance of 93.4%, whereas the abundance of other fungi, such as Chaetomium and Aspergillus, was below 1.60%. Three bacteria, including Bacillus, Lysinibacillus, and Paenibacillus, had a combined abundance of 80.5% in T80, which could be attributed to their high-temperature tolerance and symbiosis with I. lacteus. Bacterial functions, such as nitrogen cycling, cellulolysis, chitinolysis, and methylotrophy, were enriched in T60 samples, but the functions and those related to human and animal pathogen reduced in T80 samples, which promoted the growth and degradation of I. lacteus. Overall, thermotolerant fungi and spore-forming bacterial species are the dominant microorganisms in wheat straw pasteurized above 80 ℃, which promotes the colonization and degradation of I. lacteus and improves the biosafety of treated wheat straw.

The effect of post-packaging pasteurization on physicochemical and microbial properties of beef ham

In this study, we aimed to investigate the impact of three different post-packaging pasteurization temperatures (55, 65, and 75°C) on the physicochemical (pH, drip loss, texture profile, and color), microbial (lactic acid bacteria, mesophilic and psychrotrophic bacteria, as well as mold and yeast), and sensory (odor, taste, texture, color, slime, exudates, swelling, and overall acceptability) characteristics of vacuum-packed beef ham during 30 days of storage at two different temperatures (5 and 12°C).&#x0D; Lactic acid bacteria and total mesophilic and psychrotrophic counts were reduced to zero by post-packaging pasteurization at 65 and 75°C. Higher post-packaging pasteurization temperatures resulted in a significant increase in drip loss in the treated samples at 65 and 75°C, as well as a small rise in pH in all the samples. Furthermore, higher post-packaging pasteurization temperatures decreased lightness, yellowness, and h° values while increasing redness and ΔE. During post-packaging pasteurization, Chroma remained constant. The textural profile analysis revealed that post-packaging pasteurization and storage had a significant impact on the texture of beef ham. The sensory analysis showed no changes after post-packaging pasteurization in the samples, and the sensory parameters remained stable during their storage at 65 and 75 °C.&#x0D; Finally, our investigation showed that 65°C is an optimal post-packaging pasteurization temperature for increasing the shelf-life of beef ham under refrigeration.

Effect of heat treatment on the content of microorganisms in drinking milk

The microflora of raw milk is in the center of constant attention at the enterprises where it is processed. Since the microbiota of pasteurized milk is determined by the percentage of heat-resistant bacteria that are present in the milk raw material. Defects during storage are associated with the development of residual microflora of pasteurized products. The aim of the work was to determine the quantitative changes in milk microflora using different pasteurization temperatures. Pasteurization of raw milk of the first and extra grades was carried out at t = +72 °С and t = +91 °С with a holding time of 15–20 s. In pasteurized and raw milk, the residual amount of microorganisms of different groups was determined: mesophilic, psychrotrophic, lactic acid, heat-resistant, and spore-forming. It was found that in raw milk before pasteurization, the main part of the microflora was psychrotrophic and mesophilic microorganisms up to 70%, the share of lactic acid microbiota was up to 25%, heat-resistant and spore-forming bacteria were 4% and 0.8%, respectively. The temperature regime of heat treatment (t = 72 °C exposure for 20 s) contributed to the reduction of mesophilic bacteria by 93.4% when using extra grade milk and by 91.5% when using first grade milk. That is, almost 6.4 times more bacteria remain in drinking milk when raw materials of lower quality are used. The intensity of death of heat-resistant microflora of milk under the regime of 72 °C with a holding time of 20 s was only 15.2 % when using raw extra milk and 4.2 % (first). Pasteurization at a temperature of 91 °C for 20 seconds had a much stronger effect on this microflora, as its efficiency was 52.9 % and 49.2 %. That is, the efficiency of the pasteurization mode was 3.5 and 11.7 times stronger, respectively, compared to the mode at a temperature of 72 °C. Therefore, in order to apply an effective pasteurization regime at the enterprise, it is necessary to know the quantitative and qualitative composition of the microflora of raw milk.

Impact of Milk Storage and Heat Treatments on In Vitro Protein Digestibility of Soft Cheese.

Cheese is an important source of protein in the human diet, and its digestibility depends on its macro and microstructure. This study investigated the effect of milk heat pre-treatment and pasteurization level on the protein digestibility of produced cheese. An in vitro digestion method was used considering cheeses after 4 and 21 days of storage. The peptide profile and amino acids (AAs) released in digestion were analyzed to evaluate the level of protein degradation following in vitro digestion. The results showed the presence of shorter peptides in the digested cheese from pre-treated milk and 4-day ripening while this trend was not observed after 21 days of storage, showing the effect of storage period. A significantly higher content of AAs was found in digested cheese produced from milk subjected to a higher temperature of pasteurization, and there was a significant increase in total AA content in the cheese after 21 days of storage, confirming the positive effect of ripening on protein digestibility. From these results emerges the importance of the management of heat treatments on the digestion of proteins in soft cheese.

Development of Chili Sauce from Pineapple and Banana Fortified with Eggshell Calcium

Sauce is a popular condiment product. Thailand is a good source of pineapples and bananas, which are high in nutrients. Eggshell is also a source of calcium. This research developed a sauce from pineapple var. Phu Lae mixed with ripened banana var. Nam Wah and supplemented with calcium from eggshells. The suitable quantities of pineapple, banana and pineapple peel and core extract were studied based on a mixture design. The physical and chemical properties, sensory evaluation, three suitable calcium levels (0, 2, and 4%) and two pasteurization temperature levels (80-85ºC and 90-95ºC) were studied. Response surface methodology was applied and showed that all 3 components had significant effects on the sauce quality at the 0.05 level. The optimum product comprised 25.27% pineapple, 0.87% banana, 13.86% pineapple peel and core extract, 16% pickled red chili peppers, 11% pickled garlic bulbs, 26% sucrose, 2% salt, 1% vinegar, 2.12% water, and 1.88% calcium from the powdered eggshell. The product had an orange color, a pH of 4.20, and 1.61% acidity. This sauce was high in nutrients: 41.03% carbohydrate, 14.90% protein, 1.98% fat, 0.453% eggshell calcium, and 14.03 mg/kg total vitamin C. The antioxidant activity was 22.94 mg ascorbic acid/g. The optimum pasteurization temperature was 80-85ºC for 15 min. The sauce was moderately liked by panelists and has the potential to be processed into a low-cost commercial condiment.

Impact of time-temperature combinations on the anti-Cytomegalovirus activity and biological components of human milk.

There is extensive evidence that Holder pasteurization (HoP) (30 min at 62.5 °C) has harmful effects on the bioactivities of human milk (HM). We previously demonstrated that lowering HoP temperature is sufficient to inactivate Cytomegalovirus (HCMV). Here, we analyzed the effect of lowering time/temperature on the antiviral activity against HCMV and IgA levels of HM. Eighty HM samples from five mothers were pasteurized in a range of temperature (62.5-56 °C) and time (40-10 min) in a conventional setting of Human Milk Bank. Unpasteurized HM from each mother was used as control. The samples were assayed against HCMV-AD169 strain in cell cultures and IgA levels were determined by ELISA. All HM samples exhibited anti-HCMV activity, to a different extent. An improvement of antiviral activity was observed in samples treated at 60, 58 and 56 °C compared to those at 62.5 °C, with ID50 values near those of unpasteurized milk. Similarly, better retention in IgA levels was observed by reducing the temperature of treatment. We demonstrated that a 2.5 °C reduction of heat treatment significantly preserved the IgA content and fully restored the anti-HCMV activity of HM, supporting this variant of HoP as a valid alternative to preserve HM bioactivities. This work questions the standard HoP and opens the debate on whether the pasteurization temperature commonly used in Human Milk Banks should be lowered to better preserve the biological components of the milk. A reduction of HoP temperature at 60 °C determined a significant preservation of anti-HCMV activity and IgA content of donor HM, compared to standard HoP. This alternative HoP is highly feasible compared to other substitute pasteurization techniques, since it would employ the same pasteurizer equipment found in most Human Milk Banks.