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Microwave continuous-flow liquid food sterilisation, in which the liquid is mainly heated by microwaves, has the advantages of fast sterilisation speed, energy saving, comprehensive elimination, and less nutrient loss. Circular pipes are commonly used in microwave continuous-flow liquid heating processing. However, with circular pipes, which are widely used in the industry, the heating is uneven owing to the phenomenon of tube focusing when adopting external radiation. In this study, a novel microwave continuous-flow milk sterilisation system based on a coaxial slot radiator is proposed. First, the coaxial slot radiator was designed to realise efficient radiation through the establishment of multi-physics model. The structure of the system was then optimised by comparing the heating efficiency and uniformity of simulation results. The effect of microwave coaxial slot radiator rotation on heating uniformity was simulated and the results show that the heating uniformity is improved obviously. Experimental equipment was set up to verify the results of the simulation. The experimental results are consistent with the simulation results. Finally, the sensitivity analysis of the system is performed to confirm that, when the dielectric properties and types of liquid food change, the heating of the proposed microwave continuous-flow system remains efficient and uniform. [ABSTRACT FROM AUTHOR]

The injection of steam into the water or saline involve intermittent wave structures that can affect the mass and heat transfer within fluid domain. It may be analogous to the processes prevailed in milk sterilization process as the boiling point of the saline water ∼100.50C is nearly the same as the milk. Steam was injected into the rectangular duct at varying gauge pressure of 0.5, 1.0 and 1.5 bars and the proximity sensors were used to determine the disturbances over the surface of the saline water, read as the amplitudes of the waves. The wavy profiles thus found as a result of intermittent injection of steam into the saline water included the longitudinal waves, reflected waves cross-channel transverse and the edge waves. The normalized wave provided the spatial locations for the interaction regions between the surface gravity waves with the longitudinally propagating waves. The longitudinal waves and reflected waves reveals the length scales at which the incident longitudinal waves have been dissipated. These waves have been dissipated 80-90% of their amplitudes due to viscous dissipation. Thus, the relation between their growth rate and injection time has been defined based on the observed results. [ABSTRACT FROM AUTHOR]

Microwave continuous-flow liquid food sterilisation, in which the liquid is mainly heated by microwaves, has the advantages of fast sterilisation speed, energy saving, comprehensive elimination, and less nutrient loss. Circular pipes are commonly used in microwave continuous-flow liquid heating processing. However, with circular pipes, which are widely used in the industry, the heating is uneven owing to the phenomenon of tube focusing when adopting external radiation. In this study, a novel microwave continuous-flow milk sterilisation system based on a coaxial slot radiator is proposed. First, the coaxial slot radiator was designed to realise efficient radiation through the establishment of multi-physics model. The structure of the system was then optimised by comparing the heating efficiency and uniformity of simulation results. The effect of microwave coaxial slot radiator rotation on heating uniformity was simulated and the results show that the heating uniformity is improved obviously. Experimental equipment was set up to verify the results of the simulation. The experimental results are consistent with the simulation results. Finally, the sensitivity analysis of the system is performed to confirm that, when the dielectric properties and types of liquid food change, the heating of the proposed microwave continuous-flow system remains efficient and uniform.

Objective This experiment was studied the effects of various levels of crude glycerin (CG) in dairy goat diet on daily intake, milk yield, milk composition, some physical properties and some quality changes of goat milk after sterilization. Methods Twelve 75% Saanen dairy goats (body weight = 49±3 kg; days in milk = 60±12 d) were randomly assigned in a completely randomized design to evaluate the effects of three experimental diets consisting of 0%, 5%, and 10% CG (dry matter basis) which were formulated to meet or exceed the nutrient requirements of goats. Experimental dairy goats were evaluated for feed and milk yield. Milk samples were analyzed for their composition, including fatty acids, casein profile, fat globule size, and color, and were sterilized to evaluate milk heat stability. Results There were no significant differences between 0% and 5% CG treatments infeed. Increasing CG supplementation from 0% to 5% increased milk yield from 2.38±0.12 to 2.64±0.23 kg/goat/d. In addition, milk samples from 5% CG treatment had the highest total solids, fat content and lactose content, and largest fat globule size. Increasing CG to 10% resulted in a decrease in milk fat. After sterilizing at 116°C, F0 = 3 min, goat milk samples from 5% CG treatment had slightly higher sediment content and comparatively higher degree of browning. Conclusion Considering milk yield, milk fat content and quality of sterilized milk, 5% CG supplementation in a total mixed ration has a potential for implementation in dairy goats.

A microwave-assisted ultraviolet sterilization system was developed to study the synergistic effect in the sterilization of milk. Electrodeless lamps emitting ultraviolet radiation inside the microwave chamber gave a synergistic effect without challenging food safety standards. This study compared the results of both microwave and microwave assisted ultraviolet sterilizations of milk in terms of various microbial tests and physicochemical properties. The microwave-assisted ultraviolet system was found to be more effective compared to microwave alone. A significant difference (P<0.05) was observed for total plate count and methylene blue reduction test between microwave and microwave assisted ultraviolet treatment from 5 to 15 secs. Microwave-assisted ultraviolet treatment decreased the microbial count exponentially and showed <1 log (CFU ml–1) after ten seconds of treatment. During the treatment period, no significant difference was observed in the physicochemical properties of milk. [ABSTRACT FROM AUTHOR]

Dielectric properties are important for predicting dielectric heating of foodstuffs. The dielectric properties of three types of milk (raw, skimmed and concentrated non-fat) were analyzed at high frequencies between 10 MHz and 2450 MHz for producing temperatures between 20 °C and 150 °C. The study of cow milk dielectric constants (ε′ and ε″) at conditions above 100 °C is needed to evaluate dielectric sterilization of milk. The dielectric constant (ε′) was found to decrease with frequency at all temperatures but increase with temperature at low frequencies and decrease with temperature at high frequencies. The dielectric loss factor (ε″) decreased with frequency and increased with temperature in almost the entire range of frequencies. Ionic conduction was the dominant mechanism across most of the frequency range. For milk samples with higher ash content (related to salt content), ε′ was higher at low frequencies and lower at high frequencies, whereas ε″ was higher for all frequencies. Penetration depth was lower for milk samples with higher ash content. [ABSTRACT FROM AUTHOR]

Tiger nuts’ milk beverages are highly perishable products. For this reason, the interest of food industry for their commercialization makes necessary the application of preservation treatments to prolong their shelf-life. In the current study, the effect of ultra-high pressure homogenization (UHPH) on the microbiological and sensory qualities of tiger nuts’ milk beverage was evaluated. Characteristics of UHPH-treated products (at 200 and 300 MPa, with inlet temperature of 40 °C) were compared with those of raw (RP) and conventionally homogenized-pasteurized (H-P) beverages, after treatment and during cold storage at 4 °C. Microbiological quality of beverages was studied by enumerating total counts, psychrotrophic bacteria, lactobacilli, enterobacteria, molds and yeasts, and mesophilic spores. Evolution of color and sensory characteristics of beverages were also determined. Microbiological shelf-life of the tiger nuts’ milk beverages was extended from 3 to 25, 30 and 57 days by applying H-P and UHPH treatments at 200 and 300 MPa, respectively. Color of beverages was the only attribute that differentiated UHPH samples from the others, with greater luminosity and whiteness. Hence, UHPH treatments showed to be an alternative to the conventional H-P for obtaining tiger nuts’ milk beverages with an improved microbiological shelf-life and good sensorial characteristics. [ABSTRACT FROM AUTHOR]

To investigate the effects of seasonal variations and processing on cow milk fat, raw milk collected in six individual months and corresponding ultra high temperature (UHT) milk were analyzed. Similar seasonal variations in lipid classes and fatty acid composition were found in raw and UHT milk. Under commercial processing, lipid content was standardized to approximately 1.5% in UHT milk. Decreased diameter of fat droplets (around 1 µm) and thinner globule membranes were observed, as revealed using confocal laser scanning microscopy (CLSM). The distribution of lipid classes was modified with a decreased proportion of triacylglycerol accompanied by the increase of phospholipids and free fatty acids. Saturated fatty acids C12:0 and C14:0, trans-fatty acids including conjugated linoleic acid (CLA), polyunsaturated fatty acids C18:2(n-6) and C18:3(n-3), showed increased proportions in UHT milk. These results provide an indication of the effect of UHT processing on milk lipid properties. [ABSTRACT FROM AUTHOR]

Responses to milk sterilization are usually evaluated only in terms of physicochemical properties and microbial safety, thus undervaluing the importance of DNA quality in an authentication process by methods based on PCR. Because DNA is a heat-sensitive molecule, we hypothesized that the heating process may impair the detection or quantification of DNA in raw fresh milk (FM) or reconstituted milk (RM), and that differences in DNA quality might exist between FM and RM. We thus investigated the effects of sterilization on the quality of DNA extracted from FM or RM; differences in DNA quality between FM and RM were also evaluated. The quality of extracted DNA from FM or RM was assessed by the specific detection of FM or RM composition in goat milk mixtures using primers targeting the bovine 12S gene, as well as by monitoring DNA yield, purity, ratio of mitochondrial (mt) to nuclear (n) DNA, and the level of DNA degradation. Polymerase chain reaction readily detected both untreated and heat-treated FM or RM in cow-goat milk mixtures, and gave a good sensitivity threshold (0.1%) under all sterilization conditions. The DNA yield and mtDNA:nDNA ratio of FM and RM varied significantly during the sterilization process. These results demonstrated that the sterilization altered the quantification of DNA in FM or RM during sterilization, but DNA could still be readily detected in sterilized FM or RM by PCR. Furthermore, we noted significant differences in DNA integrity, yield, and mtDNA:nDNA ratio between FM and RM during sterilization, which may have potential as a means to distinguish FM and RM. [ABSTRACT FROM AUTHOR]

Objective: This experiment was studied the effects of various levels of crude glycerin (CG) in dairy goat diet on daily intake, milk yield, milk composition, some physical properties and some quality changes of goat milk after sterilization. Methods: Twelve 75% Saanen dairy goats (body weight = 49±3 kg; days in milk = 60±12 d) were randomly assigned in a completely randomized design to evaluate the effects of three experimental diets consisting of 0%, 5%, and 10% CG (dry matter basis) which were formulated to meet or exceed the nutrient requirements of goats. Experimental dairy goats were evaluated for feed and milk yield. Milk samples were analyzed for their composition, including fatty acids, casein profile, fat globule size, and color, and were sterilized to evaluate milk heat stability. Results: There were no significant differences between 0% and 5% CG treatments infeed. Increasing CG supplementation from 0% to 5% increased milk yield from 2.38±0.12 to 2.64±0.23 kg/goat/d. In addition, milk samples from 5% CG treatment had the highest total solids, fat content and lactose content, and largest fat globule size. Increasing CG to 10% resulted in a decrease in milk fat. After sterilizing at 116°C, F0 = 3 min, goat milk samples from 5% CG treatment had slightly higher sediment content and comparatively higher degree of browning. Conclusion: Considering milk yield, milk fat content and quality of sterilized milk, 5% CG supplementation in a total mixed ration has a potential for implementation in dairy goats. [ABSTRACT FROM AUTHOR]

The antimicrobial properties of copper have been recognized for several years; applying these properties to the prevention of diseases such as bovine mastitis is a new area of research. The aim of the present study was to evaluate in vitro the antimicrobial activity of copper on bacteria isolated from subclinical and clinical mastitis milk samples from two regions in Chile. A total of 327 microorganisms were recovered between March and September 2013, with different prevalence by sample origin (25 and 75% from the central and southern regions of Chile, respectively). In the central region, Escherichia coli and coagulase negative Staphylococci (CNS) were the most frequently detected in clinical mastitis cases (33%), while in the southern region S. uberis, S. aureus, and CNS were detected with frequencies of 22, 21, and 18%, respectively. Antibiotic susceptibility studies revealed that 34% of isolates were resistant to one or more antibiotics and the resistance profile was different between bacterial species and origins of isolation of the bacteria. The minimum inhibitory concentration of copper (MIC-Cu) was evaluated in all the isolates; results revealed that a concentration as low as 250 ppm copper was able to inhibit the great majority of microorganisms analyzed (65% of isolates). The remaining isolates showed a MIC-Cu between 375 and 700 ppm copper, and no growth was observed at 1000 ppm. A linear relationship was found between the logarithm of viable bacteria number and time of contact with copper. With the application of the same concentration of copper (250 ppm), CNS showed the highest tolerance to copper, followed by S. uberis and S. aureus; the least resistant was E. coli. Based on these in vitro results, copper preparations could represent a good alternative to dipping solutions, aimed at preventing the presence and multiplication of potentially pathogenic microorganisms involved in bovine mastitis disease. [ABSTRACT FROM AUTHOR]

Analytical high performance liquid chromatography (HPLC) conditions were standardized along with the isolation procedure for separation of aspartame and neotame in flavoured milk (pasteurized and in-bottle sterilized flavoured milk). The recovery of the method was approximately 98% for both aspartame and neotame. The proposed HPLC method can be successfully used for the routine determination of aspartame and neotame in flavoured milk. Pasteurization (90 °C/20 min) resulted in approximately 40% loss of aspartame and only 8% of neotame was degraded. On storage (4–7 °C/7 days) aspartame and neotame content decreased significantly ( P < 0.05) from 59.70% to 44.61% and 91.78% to 87.18%, respectively. Sterilization (121 °C/15 min) resulted in complete degradation of aspartame; however, 50.50% of neotame remained intact. During storage (30 °C/60 days) neotame content decreased significantly ( P < 0.05) from 50.36% to 8.67%. Results indicated that neotame exhibited better stability than aspartame in both pasteurized and in-bottle sterilized flavoured milk. [ABSTRACT FROM AUTHOR]

In this research the milk had been pasteurized by solar energy. It is clean energy and friendly to environment as well as available in Iraq. Circle option dish reflector was used with diameter1.5 m and focal length 80 cm, reflectivity gave at 80% and heat temperature about 200-350c. Milk container location was in optical focus of optical dish reflector. The milk had been heated at different times 10,20,30 minutes and we showed that after implanting samples tested to three genus of bacteria-contaminated milk (Staphylococcus, Klebsiella, Enterrobecter), the bacteria did not appear in 30 min heating.

Recent research has shown that mild milk thermization treatments routinely used in traditional Greek cheese production are efficient to inactivate Listeria monocytogenes and other pathogenic or undesirable bacteria, but they also inactivate a great part of the autochthonous antagonistic microbiota of raw milk. Therefore, in this study, the antilisterial activity of raw or thermized (63°C, 30 s) milk in the presence or absence of Lactococcus lactis subsp. cremoris M104, a wild, novel, nisin A--producing (Nis-A+) raw milk isolate, was assessed. Bulk milk samples were taken from a local cheese plant before or after thermization and were inoculated with a five-strain cocktail of L. monocytogenes (approximately 4 log CFU/ml) or with the cocktail, as above, plus the Nis-A+ strain (approximately 6 log CFU/ml) as a bioprotective culture. Heat-sterilized (121°C, 5 min) raw milk inoculated with L. monocytogenes was used as a control treatment. All milk samples were incubated at 37°C for 6 h and then at 18°C for an additional 66 h. L. monocytogenes grew abundantly (>8 log CFU/ml) in heat-sterilized milk, whereas its growth was completely inhibited in all raw milk samples. Conversely, in thermized milk, L. monocytogenes increased by 2 log CFU/ml in the absence of strain M104, whereas its growth was completely inhibited in the presence of strain M104. Furthermore, nisin activity was detected only in milk samples inoculated with strain M104. Thus, postthermal supplementation of thermized bulk milk with bioprotective L. lactis subsp. cremoris cultures replaces the natural antilisterial activity of raw milk reduced by thermization. [ABSTRACT FROM AUTHOR]

Highlights: [•] Thiamine dilaurylsulphate was synthesised by a new method. [•] A new formulation of thiamine dilaurylsulphate (TLS) was developed. [•] TLS formulation is a broad-spectrum bacteriostatic agent in apple juice and milk. [•] TLS formulation broadened the antimicrobial spectra of TLS by synergistic effects of organic acids. [Copyright &y& Elsevier]

Background: Milk is a valuable source of nutrients that microorganisms can grow in favorable conditions on it. This study was conducted to evaluate the microbiological quality of pasteurized and sterilized marketing milks in Bushehr. Material and Methods: This descriptive study was conducted in the autumn and early winter 2011. In this study 11 brands including 6 pasteurized, 5 sterilized brands and in total 160 samples were elevauted. Microbial tests included heterotrophic bacteria (HPC), total coliform and Escherichia coli (E.coli) were conducted according to standard methods. Results: results of this study showed that from 98 pasteurized samples, 35/7% and HPC and 15/2% of samples were contaminated by HPC and total coliform, respectively. There was no microbial contamination in all 62 sterilized samples. Mean heterotrophic bacteria in pasteurized milk was much more than Iranian national standard. Conclusion: In this research the relationship between heterotrophic and coliform bacterial growth with temperature and time variation between production date and sampling date (maintenance period) were measured and the results showed that bacterial growth had direct and significant association with temperature but there was no statistically significant association with maintenance period. [ABSTRACT FROM AUTHOR]

The effect of ultra-high-pressure homogenization (UHPH) on raw whole milk (3.5% fat) was evaluated to obtain processing conditions for the sterilization of milk. Ultra-high-pressure homogenization treatments of 200 and 300 MPa at inlet temperatures (Ti) of 55, 65, 75, and 85°C were compared with a UHT treatment (138°C for 4 s) in terms of microbial inactivation, particle size and microstructure, viscosity, color, buffering capacity, ethanol stability, propensity to proteolysis, and sensory evaluation. The UHPH-treated milks presented a high level of microbial reduction, under the detection limit, for treatments at 300 MPa with Ti of 55, 65, 75, and 85°C, and at 200 MPa with Ti = 85°C, and few survivors in milks treated at 200 MPa with Ti of 55, 65, and 75°C. Furthermore, UHPH treatments performed at 300 MPa with Ti = 75 and 85°C produced sterile milk after sample incubation (30 and 45°C), obtaining similar or better characteristics than UHT milk in color, particle size, viscosity, buffer capacity, ethanol stability, propensity to protein hydrolysis, and lower scores in sensory evaluation for cooked flavor. [ABSTRACT FROM AUTHOR]

Abstract: Conjugated linoleic acid (CLA) has been recently studied for its health-promoting and disease-preventing properties. The objective of this study was to evaluate the effect of pressure (100–600MPa), temperature (60–120°C) and treatment time (0–14min) on CLA content in milk and anhydrous milk fat (AMF) rich in CLA. In milk treated up to 14min at 100MPa, CLA was stable (>80% of retention), regardless of the temperature. In contrast, only 3.4±2% of CLA was retained at 600MPa and 120°C. For AMF, CLA retention was considerably higher (40.2±2%) than that obtained for milk. The presence of free metal ions in milk might catalyze CLA degradation. When the antioxidant catechin (1g/kg) was used, CLA retention increased significantly (>90%) in milk and AMF, regardless of the experimental conditions. Industrial relevance: Previous research led by Dr. John Kennelly resulted in CLA-enriched milk by manipulating the diet of dairy cattle. CLA in milk suffers significant losses in terms of its biological activity during processing at high temperatures like UHT. High consumption of CLA products has been associated with many health benefits. This study provided new data on CLA retention with and without an antioxidant at pressure-assisted thermal sterilization (PATS) conditions and confirmed the role of catechin in reducing oxidative damage by PATS treatments. Milk rich in CLA can be treated with PATS to deliver shelf-stable milk while CLA activity is preserved. [Copyright &y& Elsevier]

Abstract: Bacillus sporothermodurans produces highly resistant endospores that can survive ultra-high-temperature treatment in milk. The induction of endospore germination before a heat treatment could be an efficient method to inactivate these bacteria and ensure milk sterility. In this work, the rate of spore germination of B. sporothermodurans LTIS27 was measured in distilled water after high-pressure treatments with varying pressure (50–600 MPa), treatment temperature (20–50 °C), pressure-holding time (5–30 min) and post-pressurization incubation time (30–120 min) at 37 °C or 4 °C. The results showed that pressure-induced germination was maximal (62%) after a treatment at 200 MPa and 20 °C and increased with pressure-holding time and post-pressurization incubation time. Treatment temperature had no significant effect on germination. A central composite experimental design with three factors (pressure, pressure-holding time, and post-pressurization incubation time) using response surface methodology was used to optimize the germination rate in distilled water and in skim milk. No factor interaction was observed. Germination was induced at lower pressure and was faster in milk than in distilled water, but complete germination was not reached. The optimum germination obtained with experimental data was 5.0 log cfu/mL in distilled water and 5.2 log cfu/mL in milk from 5.7 log cfu/mL of spores initially present in the suspension. This study shows the potential of using high hydrostatic pressure to induce the germination of B. sporothermodurans spores in milk before a heat treatment. [Copyright &y& Elsevier]

Goat milk with and without stabilizing salt was subjected to in-container and UHT sterilization. Heat stability was assessed by measuring the amount of sediment in the milk. Without stabilizing salts, goat milk usually produced less sediment when subjected to incontainer sterilization compared with UHT processing. Addition of stabilizing salts up to 12.8 mM resulted in a progressive increase in sediment for in-container sterilization. In contrast, adding stabilizing salts at 6.4 mM initially reduced sediment formation in UHT-treated milk but addition of stabilizing salts at 12.8 mM increased sediment formation. Adding stabilizing salts to goat milk increased pH, decreased ionic calcium, and increased ethanol stability. Adding up to 2 mM calcium chloride increased sediment formation more after UHT treatment than after in-container sterilization. These results suggest that no single mechanism or set of reactions causes milk to produce sediment during heating and that the favored pathway is different for UHT and in-container sterilization processes. Poor heat stability could be induced both by increasing ionic calcium and by decreasing it. Ethanol stability is not a good indicator of heat stability for in-container sterilization, but it may be for UHT sterilization, if milk does not enter the region of poor heat stability found at low concentrations of ionic calcium. [ABSTRACT FROM AUTHOR]

Abstract: Sterilization of milk protein without heating is of great interest. Gamma irradiation is a very powerful method to decontaminated casein. Gamma-irradiation of proteins in aqueous media at doses higher than 5kGy is known to induce their aggregation (without oxygen) or degradation (in presence of oxygen). Camellia sinensis green tea extract addition before irradiation of caseins cow milk proteins was examined. It was found that the presence of C. sinensis green tea extract during irradiation in the presence of oxygen conditions prevented the protein aggregation even at doses higher than 10kGy, probably by scavenging oxygen radicals produced by irradiation. The protective role of C. sinensis green tea extract allowing the gamma-irradiation treatment of caseins cow milk proteins in solution, was asserted by sodium dodecyl-sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and by high performance liquid chromatography inverse phase (RP-HPLC). The total viable microorganisms content evaluated by Plate Count Agar (PCA) incubation for 12h at 37°C, showed that caseins protein preparations gamma-irradiated remained sterile at a dose 2kGy in absence of C. sinensis green tea extract and at a dose lower than 2kGy in the presence of C. sinensis green tea extract. [Copyright &y& Elsevier]

The purpose of this study was to establish a rationale for the cleaning of microfilteration (MF) membranes fouled by milk. Milk was processed using a hydrophilic GVWP membrane. Fouling is the most important problem associated with the membrane-based milk sterilization process. This is mostly due to the deposition of bacteria, fats, proteins, and minerals on the membrane surfaces. In the first part of this work, the factors affecting the chemical cleaning efficiency were studied. This includes the effect of concentration, temperature, cleaning time, and cross-flow velocity. A wide range of cleaning agents including acids, bases, and surfactant was used. Flux recovery (FR) was employed for presenting the cleaning efficiency. In the second part of this study, FR was optimized using response-surface methodology with a face-centered central composite design (CCF). This was employed to create the mathematical model and minimize the number of experiments. [ABSTRACT FROM AUTHOR]

The preservation of raw ovine, bovine and caprine milks by the activation of their natural lactoperoxidase (LP) systems was investigated. The LP system of the samples was activated by adding different amounts of sodium thiocyanate and sodium percarbonate to give three different concentrations of thiocyanate and hydrogen peroxide: 7, 14 and 28 mg/L and 15, 30 and 60 mg/L, respectively. Each type of raw milk, ovine, bovine and caprine, was analysed after being treated as follows: Control (C), LP inactivated (T0), LP activated with different concentrations of thiocyanate (7, 14 and 28 mg/L) and hydrogen peroxide (15, 30 and 60 mg/L) and stored at 4°C for 72 h. The results indicated that concentrations of 28 mg/L (SCN) and 60 mg/L (HO) would be adequate for preserving milks of different mammals at 4°C, but we should take into consideration the international norm - 14 mg/L of SCN and 30 mg/L of HO, respectively. Overall, the results have shown that, by activation of the LP system in raw milk, it was possible to store ovine, bovine and caprine milks at 4°C for several days. Changes in titratable acidity, total colony counts, psychrotrophic bacteria, coliforms, moulds and yeasts of the milk samples were followed during storage at low temperature with increasing dose. The effect of doses was greater in bovine milk than in caprine milk and finally in ovine milk. [ABSTRACT FROM AUTHOR]

Abstract: Traditional and novel approaches for the calculation of the heat treatment efficiency are compared in this work. The Mild Heat value (MH-value), an alternative approach to the commonly used sterilisation, pasteurisation and cook value (F, P, C-value), is calculated to estimate the efficiency of a mild heat process. MH-value is the time needed to achieve a predefined microbial reduction at a reference temperature and a known thermal resistant constant, z, for log-linear or specific types of non-log-linear microbial inactivation kinetics. An illustrative example is given in which microbial inactivation data of Listeria innocua CLIP 20-595 are used for estimating the inactivation parameters under isothermal conditions of 58, 60, 63 and 66 °C by the use of the log-linear and the model. Thereafter, dynamic temperature profiles (targeting at 54 and 57 °C) representing milk thermisation are exploited for illustrating the application of MH-value. Finally, the equivalent holding times of different temperatures are calculated taking into account the observed non-linearity. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the effect of somatic cell counts (SCC) in milk on plasmin and plasminogen activities of ultra high temperature (UHT) milk during storage. Raw milks were categorized in SCC groups of low (342,000-487,000 cells mL-1) and high cells (603,000-808,000 cells mL-1). Two replicates of UHT milks within each SCC category were analyzed for plasmin and plasminogen activities after 10, 30, 60, 90 and 120 days of storage at room temperature. For manufacture of UHT milk, raw milk was pasteurized and sterilized by direct vapor injection process, followed by aseptic packaging. SCC had no effect on physical-chemical characteristics of raw milk, and on plasmin or plasminogen activities in raw and UHT milks during 120 days of storage. However, independently of the SCC in raw milk, the activity of plasmin and plasminogen increased in UHT milk during storage, hence indicating a possible increase in proteolysis in the product during its shelflife. [ABSTRACT FROM AUTHOR]

This paper introduces a new concept and method for long-term sterile storage of turbid product, which is potentially subject to microbial contamination. The method uses intermittent delivery of pulsed electric fields (IDPEF) throughout the storage at time intervals that are prescribed according to microorganisms' growth kinetics. This new approach facilitates sterile storage without the need for chemical preservatives, additives, radiation or the complex infrastructure demanded by refrigeration. Unlike ultraviolet radiation, IDPEF can be used in turbid media. The first part of this paper is a theoretical discussion on the growth kinetics of microorganisms treated by IDPEF. We then provide a preliminary experimental study on the kinetics of microorganism growth in a turbid microbial growth media as a function of the IDPEF delivery intervals. Last, we demonstrate the use of the method using milk as a medium. IDPEF of 30 pulses, 17.5 kV/cm field strength, 40 \mu \s long, 1 Hz delivered every 12 h was found to have the ability to preserve milk in a non-sterile environment at room temperature as effectively as refrigeration at 4 ^\circ\C. The method has many obvious applications in biotechnology, the food industry, and is of particular importance with regard to geographical areas lacking refrigeration for storage of pharmaceuticals and food. This study was performed on the laboratory scale and a substantial adaptations are required in order to apply it to the industrial scale. [ABSTRACT FROM PUBLISHER]

This study was conducted to determine effects of homogenization treatments under different pressures (150, 200 and 250 kg/cm2) on some physical, chemical, microbiological and sensory properties of ayran throughout the storage period of 1, 7 and 14 days. Whey separation of samples decreased while viscosity values increased with the increased homogenization pressure (P<0.05). It was identified that different homogenization pressures had no significant effects on chemical, microbiological and sensory properties of ayran samples (P>0.05). [ABSTRACT FROM AUTHOR]

Abstract: The effect of retort temperature, rotation speed, headspace and radius of rotation on mean convective heat transfer coefficient during sterilisation of canned evaporated whole milk was studied. The mean total solids content of evaporated milk obtained in a pilot plant installation was 25.25 g/100 g. Processing variables used ranged as follows: retort temperature: 117–123 °C; speed of rotation: 10–20 rpm; headspace: 4–12 mm; radius of rotation: 3.5–16.5 cm. The model developed for heat transfer coefficient was adequate, showing no significant lack of fit and satisfactory coefficient of determination. Retort temperature, speed of rotation, headspace and radius of rotation have a significant effect. Dimensional correlations were developed for convective heat transfer coefficient, in terms of Nusselt number as a function of Reynolds number, Prandtl number and relative headspace; the best agreement was obtained using the diameter of rotation as the characteristic dimension. [Copyright &y& Elsevier]

Dialysis and ultrafiltration were investigated as methods for measuring pH and ionic calcium and partitioning of divalent cations of milk at high temperatures. It was found that ionic calcium, pH, and total soluble divalent cations decreased as temperature increased between 20 and 80°C in both dialysates and ultrafiltration permeates. Between 90 and 110°C, ionic calcium and pH in dialysates continued to decrease as temperature increased, and the relationship between ionic calcium and temperature was linear. The permeabilities of hydrogen and calcium ions through the dialysis tubing were not changed after the tubing was sterilized for 1 h at 120°C. There were no significant differences in pH and ionic calcium between dialysates from raw milk and those from a range of heat-treated milks. The effects of calcium chloride addition on pH and ionic calcium were measured in milk at 20°C and in dialysates collected at 110°C. Heat coagulation at 110°C occurred with addition of calcium chloride at 5.4 mM, where pH and ionic calcium of the dialysate were 6.00 and 0.43 mM, respectively. Corresponding values at 20°C were pH 6.66 and 2.10 mM. [ABSTRACT FROM AUTHOR]

Abstract: The high-pressure sterilization establishment requires data on isobaric and isothermal destruction kinetics of baro-resistant pathogenic and spoilage bacterial spores. In this study, Clostridium sporogenes 11437 spores (107 CFU/ml) inoculated in milk were subjected to different pressure, temperature and time (P, T, t) combination treatments (700–900MPa; 80–100°C; 0–32min). An insulated chamber was used to enclose the test samples during the treatment for maintaining isobaric and quasi-isothermal processing conditions. Decimal reduction times (D values) and pressure and temperature sensitivity parameters, ZT (pressure constant) and ZP (temperature constant) were evaluated using a 3×3 full factorial experimental design. HP treatments generally demonstrated a minor pressure pulse effect (PE) (no holding time) and the pressure hold time effect was well described by the first order model (R 2 >0.90). Higher pressures and higher temperatures resulted in a higher destruction rate and a higher microbial count reduction. At 900MPa, the temperature corrected D values were 9.1, 3.8, 0.73min at 80, 90, 100°C, respectively. The thermal treatment at 0.1MPa resulted in D values 833, 65.8, 26.3, 6.0min at 80, 90, 95, 100°C respectively. By comparison, HP processing resulted in a strong enhancement of spore destruction at all temperatures. Temperature corrected ZT values were 16.5, 16.9, 18.2°C at 700, 800, 900MPa, respectively, which were higher than the thermal z value 9.6°C. Hence, the spores had lower temperature sensitivity at elevated pressures. Similarly, corrected ZP values were 714, 588, 1250MPa at 80, 90, 100°C, respectively, which illustrated lower pressure sensitivity at higher temperatures. By general comparison, it was concluded that within the range operating conditions employed, the spores were relatively more sensitive to temperature than to pressure. [Copyright &y& Elsevier]

Abstract: The effect of small-molecule surfactants on the stability of sterilised milk (with added sterol esters) was determined by measurement of the sensitivity towards renneting, and of particle size upon freeze-thaw treatment. Water-soluble surfactants like diacetyl tartaric esters of monoglycerides and sodium stearoyl lactylates reduced freeze-thaw stability and the rate of renneting. Oil-soluble surfactants, like monoglycerides and citric acid esters of monoglycerides had an opposite effect. Water-soluble surfactants could coat the proteins and render casein micelles more dense; hence they could reduce age gelation through reduced access by enzymes. The same surfactants, however, also coated the outside of the micelles and rendered them more hydrophobic, which resulted in reduced colloidal stability. The oil-soluble surfactants had an opposite effect: they accelerated renneting, and improved colloidal stability. Because of the latter they are alternatives to polyphosphates or carrageenan. We also found indications that polyphosphates increased protein-enzyme repulsion. [Copyright &y& Elsevier]

Abstract: Control milk and milk enriched with unsaturated fatty acids (3.3% fat) were heated using an indirect ultra-high temperature treatment, then stored at 20 °C in containers from different packaging materials: glass (no exposure to light), high density polyethylene (HDPE) packaging with light barrier (3-HDPE; no exposure to light) and monolayer HDPE (1-HDPE; 1000 lx). The decrease in antioxidant content and the formation of oxidation products were monitored over three months. For milk stored in 1-HDPE packaging, the available antioxidants were consumed at the same rate for both milk types, suggesting that oxidation is initiated in the serum phase. After depletion of these antioxidants, oxidation products were formed according to the fatty acid profile. When using a light barrier in the packaging, no oxidation products could be detected over three months. [Copyright &y& Elsevier]

Abstract: Low-heat skim milk powder (SMP), reconstituted to 25% total solids, was found to have poor heat stability. This could be improved by reducing the free Ca2+ concentration to 1.14mm, or lower, by the addition of either Amberlite IR-120 ion-exchange resin in its sodium form or tri-sodium citrate in skim milk prior to evaporation and spray drying. Reduction in Ca2+ concentration was accompanied by increases in pH, particle size, and kinematic viscosity, and by a reduction in ζ-potential and changes in colour. In-container sterilisation of the reconstituted powder increased particle size, ζ-potential, kinematic viscosity and a* and b* values. However, Ca2+ concentration, pH and whiteness decreased. This study elucidated the importance of Ca2+ concentration and pH on heat stability of low-heat SMP, suggesting that Ca2+ concentration and pH in bulk milk are useful indicators for ensuring that spray dried milk powder has good heat stability. [Copyright &y& Elsevier]

Abstract: The total antioxidant capacity (hydrophilic plus lipophilic) of sixteen different commercial samples of pasteurized and ultra high temperature (UHT) treated milk was determined using the oxygen radical absorbance capacity assay using fluorescein as a fluorescent probe. A significant correlation between the percentage of fat and the value of the total antioxidant capacity was found in milk samples obtained from the same batch of raw milk. Analyses of the whole milk, whey and deproteinized milk showed that the major contributor to the total antioxidant capacity of whole milk was the casein fractions, while albumin was the major contributor to the total antioxidant capacity of whey protein. Hydrophilic antioxidant compounds, such as vitamin C and uric acid, were the main contributors to the total antioxidant capacity of the deproteinized milk. Significant differences in total antioxidant capacities were found between whey and deproteinized samples obtained from pasteurized and UHT-treated milk, the values being higher for the former. [Copyright &y& Elsevier]

The article presents a study which examines the thermal deactivation kinetics of lactococcus lactis. It states that both the survival data and the calculations made using the reduced model showed that skim milk is a more preventive medium than M17 broth within the attempted temperature range. It mentions that the reduced model and the process used can be applied for other phages whose endurance curves are sigmoid.

The article presents information about the history of sterilized milk distribution in Fécamp, France. It is noted that French doctor Léon Dufour was responsible for beginning the distribution in 1894. The social implications of introducing feeding bottles and milk sterilizers to the public are described.

Abstract: Extraction of 2,4,6-tribromophenol (TBP), pentachlorophenol (PCP) and pentachloroanisole (PCA) from whole fat cow milk using headspace solid-phase microextraction (HS-SPME) with polyacrylate (PA) and polydimethylsiloxane (PDMS) fibers was evaluated and compared. The PA was studied to extract PCA, TBP and PCP, while PDMS was used to extract PCA and acetyl derivatives of PCP and TBP. The parameters: fiber position, matrix effect, temperature and extraction time were studied. The analysis was made by gas chromatography coupled with mass spectrometry. The results show that the distance between fiber and milk had a significant effect on the extraction kinetics. Also, the fat content in milk was a critical parameter that clearly affected the extracted mass of each compound. By using a PA fiber, the sensitivity for PCA and TBP was higher than that obtained with PDMS fiber; however, PA fiber did not allow PCP determination. The recoveries from milk were 95±4%, 96±2% and 96±4% for PCP, TBP and PCA, respectively, with the PDMS fiber and 94±3% and 95±1% for TBP and PCA, respectively, with PA fiber. The method using PDMS fiber was applied to real whole milk samples. [Copyright &y& Elsevier]

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Abstract: Studies of the formation of soluble κ-casein/whey protein (WP) complexes in heated (90°C10min−1) milk and related mixtures of proteins have been made. The use of milk samples containing different genetic variants, and having different compositions, allowed the effects of changing the natural protein balance on the formation of particles to be investigated. In addition, studies were made of the effects of addition of WP or of purified κ-casein to the milk samples. The addition of WP caused an increase in the amount and the size of the complexes, but addition of κ-casein to the milk had little or no effect on the complex formation, nor did it seem that the added κ-casein could react with the WP in the milk. Conversely, in systems where the casein micelles were absent, the purified κ-casein reacted well with WP, suggesting that in milk heated at its normal pH the WP react preferentially with the κ-casein on the casein micelles. [Copyright &y& Elsevier]

Abstract: Milk fouling is the main cause of progressive decline in the rate of heat transfer in a UHT milk sterilizer, which results in a drop in milk outlet temperature as the processing advances. Increasing steam temperature is one of the ways to overcome the drop in milk outlet temperature and prolong the operating time before the processing is stopped for cleaning of deposits in the heat exchanger. A computer model is developed for accurate control of milk temperature as affected by fouling. It can calculate accurately the increase in steam temperature required for maintaining the desired milk sterilization temperature. The results with steam control are compared with the results without any control and this procedure was found satisfactory for controlling the milk outlet temperature. The procedure described can be applied to any heat exchanger with minor modifications, if necessary. [Copyright &y& Elsevier]

The effects of some physical treatments of milk (pasteurization and homogenization at 1000 bar) on the evolution of the microbial populations, as well as on the proteolytic and lipolytic profiles, of Crescenza, a traditional Italian soft cheese, were studied in relation to its shelf-life. The dynamic, high-pressure homogenization (HPH) treatment of milk caused a reduction in the cell loads attained by the expiry date of yeasts and Pseudomonas spp. Moreover, the thermal and HPH treatments had different selective actions on the yeast populations, the former favouring oxidative species. In addition, the Crescenza obtained using milk treated at 1000 bar showed evidence of early and significant lipolysis. [ABSTRACT FROM AUTHOR]

Examines the survival times of Campylobacter coli in sterilized buffalo milk. Agents of bacterial diarrhea; Conditions of salubrity and hygiene; Presence of flora or indigenous systems in normal milk.

Determines the feasibility of membrane-sterilizing immunoglobulin G (IgG) and aseptically adding it to ultra-high temperature (UHT) products. Stability of IgG in UHT products; Concentrations of IgG at 4, 25 and 35 degrees Centigrade over five months; Thinning of milk when stored at 25 and 35 degrees Centigrade; D values for thermal destruction of IgG.

Assesses the potential for practical applications of high pressure inactivation in the food industry using Clostridium thermoaceticum, in regard to the sterilization of quality in canned milk for coffee. Mechanisms of pressure sterilization for thermoduric spores; Mechanism of protein denaturation by high pressures.

The article presents a study on the levels of hexachlorobenzene (HCB) in Spanish sterilized milk, along with the influence of the sterilizing process on the said levels. The study involves 208 samples of Spanish sterilized milk, and a Hewlett Packard 5890 gas chromatograph with electron capture detector was used to determine the HCB levels. The result shows that the concentration of HCB in Spanish sterilized milk has been reduced by around 93 percent.

The article discusses the Draft Ministerial Decree issued by Italy government regarding the long-life milk and dairy products labeling. The draft provides that the label must show the place of origin of the milk used on sterilized shelf-stable milk, ultra-high-temperature (UHT) processed milk, and microfiltered pasteurized milk. Moreover, the provision would also be enforced to products at the point of sale, and pre-wrapped or pre-packed at the point of sale or on any adjoining premises.