Heat Treatment Of Milk Research Articles

Validation of the AnticFast® Beta-Lactams Rapid Test Kit for Detection of Beta-Lactams (Penicillins and Cephalosporins) in Raw Cow's Milk: AOAC Performance Tested MethodSM 032303.

AnticFast® Beta-Lactams Rapid Test Kit is a qualitative two-step (2 min + 5 min) rapid lateral flow assay to detect β-lactam (penicillins and cephalosporins) antibiotic residues in raw commingled cow's milk. The method performance was evaluated according to Commission Decision 2002/657/EC, Commission Implementing Regulation 2021/808, and Community Reference Laboratories Residues Guidelines for the Validation of Screening Methods for Residues of Veterinary Medicines. The AnticFast Beta-Lactams Rapid Test Kit was evaluated for detection capability, selectivity, false-positive results, repeatability, robustness, suitability for various milk types and milk compositions, milks from various species, and test kit consistency and stability. Samples included milks spiked at concentrations bracketing the EU maximum residue limits (MRLs) for β-lactams as well as bulk farm and tanker milks. The AnticFast Beta-Lactams Rapid Test Kit is specific for the detection of β-lactams in milk and does not detect compounds from other antibiotic families. Interference was seen with clavulanic acid, a β-lactamase inhibitor, which was expected. The test can detect all residues of β-lactams (penicillins and cephalosporins) present on the EU-MRL list for milk at their respective MRL except for desfuroylceftiofur and cephalexin, which were above the MRL. No false positives were detected in the 602 (300 blank farm and 302 tanker load) samples tested. Robustness testing indicated that the detection in heat-treated milk types may be slightly hampered. For substances with a detection capability well below the MRL, this interference does not cause problems since detection at MRL remains guaranteed, but care should be taken for substances with a CCβ at or near their MRL. Diminished sample flow was seen with reconstituted milk powder and blank ewes' milk, so sample flow should always be verified for these milk types. Results of this validation show that the AnticFast Beta-Lactams Rapid Test Kit is a reliable test for rapid screening of raw cows' milk for residues of β-lactam antibiotics. AnticFast Beta-Lactams Rapid Test Kit is an easy, realiable, robust and highly specific test for screening of raw cows' milk for residues of penicillins and cephalosporins.

Modelling the reaction kinetics of β-lactoglobulin and κ-casein heat-induced interactions in skim milk

Levels of native beta-lactoglobulin (β-lg) in heat-treated milk are often used as a measure of quality deterioration. Most kinetic studies to date on β-lg denaturation have been simplified to a single step model, which limits its application in various processing conditions. Furthermore, this denaturation of β-lg is only an initial stage in a series of interactions to take place. In this work, a multistep model for the denaturation of β-lg and its subsequent reaction with κ-casein was developed. This model was used to rationalize the concentrations of native β-lg and κ-casein determined from HPLC. Notably, this model provides a clear account of the influence of β-lg on the loss of micelle-bound κ-casein. The various reaction rates reveal reactions are limited by the rate at which sulfhydryl-disulfide reactions connect proteins while the effect of intermolecular forces is minimal.

High prevalence of multidrug-resistant Campylobacter jejuni in sheep and goats milk in Jordan

The prevalence and resistance of Campylobacterjejuni in small ruminants in Jordan to antimicrobials of human clinical importance and the management factors that associate with C. jejuni in the flocks were determined. Flock-level prevalence of C. jejuni was 28.5%; individual animals’ prevalence was 11.0%. Flocks that reported abortions within the immediate last season had 2.7 × higher likelihood of C. jejuni occurrence than flocks that did not report abortions in the immediate last season. More than 75% of C. jejuni isolates were resistant to ampicillin, nalidixic acid, streptomycin, and erythromycin; the lowest resistance was toward amoxicillin-clavulanic acid. Overall, 70.1% of the isolates were multidrug-resistant (resistant to ≥3 antimicrobial classes); 51.7% were resistant to ≥5 antimicrobial classes. Sheep isolates generally showed significantly higher resistance percentages than goat isolates. The results highlight the probability of small ruminants as a source of campylobacteriosis in human and the importance of the heat treatment of milk.

Detection of Salmonella Enteritidis in Milk Using Conductometric Immunosensor Coated on Polyaniline/Zinc Oxide Nanocomposite.

The demand for rapid and accurate detection methods for Salmonella Enteritidis necessitates the development of highly sensitive and specific biosensors to ensure proper monitoring of food safety and quality requirements in the food sector and to secure human health. This study focused on development of a polyaniline/zinc oxide (PANI/ZnO) nanocomposite film on a gold electrode conductometric immunosensor for detection of Salmonella Enteritidis. The sensor was modified with monoclonal anti-Salmonella Enteritidis antibodies as biorecognition elements. The fabricated sensor was able to detect and quantify the target pathogen within 30 min and showed a good detection range from 101 to 105 colony-forming units (CFU)/mL for Salmonella Enteritidis and a minimum detection limit of 6.44 CFU/mL in 0.1% peptone water. Additionally, the fabricated sensor showed good selectivity and detection limit toward the target bacterium and successfully determined Salmonella Enteritidis content in ultrahigh heat-treated skim milk samples without pretreatment of the food sample.

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.

Effect of coagulation temperature on cooking integrity of heat and acid-induced milk gels

Heat and acid-induced milk gels do not melt or flow upon heating and thus show great potential as a dairy-based protein source for cooking, e.g. for stews. Understanding how processing, e.g. acidification, affects the cooking behavior of these gels is therefore of great industrial interest.The cooking integrity of gels produced by rapidly acidifying milk using citric acid at temperatures of 60, 75, and 90 °C, was determined by analyzing composition, texture, and spatial water distribution before and after cooking.Increasing the acidification temperature from 60 to75 °C resulted in a significant reduction of yield, due to decreased moisture content of the gels. With increasing content of solids, the gels grew harder and denser, as observed by texture profile analysis and low-field Nuclear Magnetic Resonance. Upon cooking the 60 °C gel lost a significant amount of moisture, due to the contraction of the porous protein network. The more compact gels, prepared at 75 and 90 °C, did not lose mass indicating good cooking integrity, i.e. a gel that keeps its structure during cooking.Acidification temperature thus greatly influenced cooking integrity. The effect was mainly ascribed to the density of the gel texture, a result of the speed of protein aggregation and calcium recovery.

Effects of ultra-high-temperature processes on metabolite changes in milk.

Processing can affect milk properties and alter the composition of milk metabolites, which has corresponding effects on milk flavor and quality. It is quite important to study the safe quality control of milk processing. Therefore, the purpose of this study was to identify metabolites at different steps of ultra-high-temperature-sterilized (UHT) milk processing using gas chromatography-mass spectrometry (GC-MS). These steps included raw milk, pasteurized milk (80°C for 15 s), semi-finished milk (after pasteurizing, it was homogenized at 75°C with pressure of 250 bar), UHT milk (at 140°C for 10 s), and finished milk (homogenized UHT milk). A total of 66 metabolites were identified across all samples, including 30 metabolites in the chloroform layers of the milk samples and 41 metabolites in the water layers; 5 metabolites were found in both layers. The metabolites were primarily fatty acids, amino acids, sugars, and organic acids. For example, pasteurized and ultra-high-temperature-sterilized kinds of milk had lactose contents similar to those of raw milk, with increases in saturated fatty acids such as hexadecanoic acid and octadecanoic acid. Additionally, these findings indicated that these methods of processing can affect the contents of some components of milk. Therefore, from the perspective of milk's nutritional value and consumer health, the excessive heating of dairy products should be avoided and the milk heat treatment process should be standardized from the source.

Factors affecting the microbiological quality and contamination of farm bulk milk by Staphylococcus aureus in dairy farms in Asella, Ethiopia

BackgroundThe determination of the microbiological quality and safety of raw milk and the associated influencing factors at the farm level is very critical given that the quality or safety of subsequent products that are further produced depends on this. Therefore, this study aimed to determine the microbiological quality and safety of bulk milk and identify associated risk factors, and assess the presence/absence of S. aureus in bulk milk with potential contaminating sources in dairy farms in Asella, Ethiopia.ResultsThe geometric means of bacterial counts in farm bulk milk were 5.25 log cfu/ml, 3.1 log cfu/ml and 2.97 log cfu/ml for total bacterial count (TBC), coliform count (CC) and coagulase-positive staphylococci count (CPS), respectively. Of the 50 dairy farms, 66, 88, and 32% had TBC, CC and CPS counts, respectively, that exceeded the standard international limits for raw cow’s milk intended for direct human consumption. TBC tended to increase as CC increased in bulk milk (r = 0.5). In the final regression model, increased TBC, CC and the contamination of farm bulk milk by S. aureus were significantly associated with dirty barns, dirty cows and soiled udder and teats. TBC was higher during the rainy season than during the dry season. The reported practice of washing teats with warm water significantly decreased CC and CPS. The occurrence of S. aureus was significantly (p < 0.05) higher in bulk farm milk (42%) than in pooled udder milk (37.3%), teat swabs (22.5%), milkers’ hand swabs (18%), bulking bucket swabs (16.7%), milking container swabs (14%), and water for cleaning of udder and milkers’ hands (10%). The questionnaire survey result showed widespred raw milk consumption habits, low level of training and poor hygienic milking practices.ConclusionsThis study revealed low-quality bulk farm milk with high bacterial counts and a high occurrence of S. aureus. This indicates the potential food safety risks due to consumption of raw milk or its products. This study suggests awareness creation to dairy farmers and the public on hygienic milk production and heat treatment of milk before consumption.

Chemical characteristics, oxidation and proteolysis in cheese produced from fresh or stored milk subjected to heat treatments

Cheese produced from fresh, stored or heat pretreated (65°C for 15 s) milk subjected to pasteurisation (72°C or 77°C for 15 s) was studied for chemical characteristics and proteolysis after 4 and 21 days of storage. Antioxidant activity was higher in cheese from fresh milk than in cheese from stored and heat pretreated milk. Malondialdehyde content as an index of lipid oxidation increased in cheese made with pretreated and preserved milk than in cheese made with fresh milk. Antioxidant activity and lipid oxidation were not significantly affected by pasteurisation temperature. Proteolysis increased during cheese maturation regardless of milk heat treatments.

Maximising olive oil by‐products

Maximising olive oil by‐products

O-192 Superoxide dismutase-rich melon extract supplementation helps improve heat stress adaptation and milk quality of dairy goats

O-192 Superoxide dismutase-rich melon extract supplementation helps improve heat stress adaptation and milk quality of dairy goats

Protective influence of heat treatment on the light-induced riboflavin (vitamin B2) degradation in dairy products

Milk is the most important source of riboflavin (Vitamin B2) in many nations. Riboflavin absorbs light in the ultraviolet region and generates singlet oxygen in milk leading to the oxidation of nutrient components and affects the sensory quality of dairy products. The purpose of this work was to elucidate the effect of heat-treatment on the light-induced riboflavin degradation in the model solution of milk bases and milk samples. Although the photo-degradation of riboflavin in all samples was decreased with the increasing of illumination time, the reductions of riboflavin light oxidation were found in all milk model samples and heated milks in according to the formation of Maillard reaction products during heating. The amount of riboflavin remained in control sample (1.5 mg/l riboflavin) was 1.67 % after 2.5 hour illumination. But, it was 34 % and 60 % in the heated lactose and casein solution and milk at 120oC, 45 min, respectively. The increasing of heating time leaded to the increasing of protective ability of milk and model samples against riboflavin photo-degradation. The study clarified that heat treatment of whey proteins, casein and milk might induce the formation of Maillard reaction products that enhanced the protective ability against photo-degradation of riboflavin.

The effect of acidification temperature and pH on intermolecular protein bonds and water mobility in heat and acid-induced milk gels

Pre-heated milk was gelled by acidification at 60, 70, 80, and 90 °C, to pH 5.2 or 4.6. The resultant milk gels were characterised in terms of composition, molecular protein bonds, and water mobility. The protein network structure of the gels was mainly governed by calcium bonds (30–63%), independent of the acidification temperature and pH. However, acidification temperature affected the aggregation kinetics and buffer capacity of the milk. Increased temperature led to an increase in total calcium in the gels (187% and 71% for pH 5.2 and 4.6 respectively) since colloidal calcium phosphate dissociated to a lesser degree, increasing the calcium bonds in the protein structure network. The largest water population in the gels was assigned to protons entrapped within the protein network, and the transverse relaxation time decreased with both increase in acidification temperature and decrease of pH, due to the increasing density of the gel aggregates.

Forest Dwellers’ Dependence on Forest Resources in Semi-Arid Environments

Forests remain an important resource in Iran, as most of the livelihood activities of local communities, especially in the semi-arid environment of the Zagros forests, are dependent on forest resources. The aim of this study was to identify the type and extent of forest dependency. Semi-structured interviews and questionnaires were used to collect data from 170 households in Central Zagros. Results show that using firewood for fuel and non-fuel uses, harvesting edible and medicinal plants, agriculture and horticulture, and livestock grazing were the main forest livelihood activities undertaken by the households in the study area. On average, each household harvested 18.08 cubic meters of oak per year for water heating (bathing), baking bread, heating, cooking, heating milk and buttermilk, agricultural tools, house building, warehouses and shelters, fencing, branches for livestock, charcoal and harvesting firewood for sale. Of rural households, 72% used edible plants, and 86% used medicinal plants. Age, job, residence status, number of livestock, crop farming and household size were found to be correlated with forest dependency. Findings from this study contribute broadly to an integrated understanding of the bio-human dimensions of forest ecosystems, with specific reference to the study area.

Protein modifications due to homogenisation and heat treatment of cow milk.

This research paper aimed to locate protein modifications caused by treatment of milk and determine if the modification locations were consistent. The majority of milk for consumption is homogenised using pressure and heat, and this causes changes in the location of proteins in the milk as well as protein modifications. To investigate these proteomic changes, raw milk was pasteurised (72°C, 15 s), then, to separate the treatment for homogenisation, heated at these different pressures and temperatures: 45°C without no pressure applied, 45°C with 35 MPa, 80°C without pressure applied and 80°C, with 35 MPa. Proteomic analysis was done after separating the milk into three fractions: whey, casein and cream. Protein modifications in each fraction were examined and we found Maillard products as well as oxidation to be of interest. The proteins were also further identified and characterised to compare protein modification sites and differences in proteins present in the cream resulting from homogenisation and/or pasteurisation. This experiment showed that both heat and pressure during homogenisation can cause increases in protein modifications as a result of oxidation or the Maillard reaction. Total cysteine oxidation and total proline oxidation differed between treatments although this was only significantly different for cysteine. It was observed that protein modifications occurred in the same location in the protein sequence rather than in random locations which we highlighted by examining α-S1-casein, lactadherin and β-lactoglobulin.

Accelerating Tolerance Induction In Cow's Milk Allergic Children By Heated Cow's Milk Protein: The iAGE Follow-up Study.

Cow’s milk allergy (CMA) is a prevalent disorder in Western countries. We studied putative tolerance induction and safety of a heated cow’s milk protein in a RCT in eighteen children with diagnosed cow’s milk allergy.

Effects of heat treatment, plant coagulant, and starter culture on sensory characteristics and volatile compounds of goat cheese

The effects of heat treatment, coagulant source, and starter culture addition on the physicochemical, sensory characteristics, and volatile compounds of goat cheese were evaluated. For this purpose, the goat cheese was produced from raw milk or heat-treated milk coagulated with Cynara cardunculus L. protease or calf rennet. The effect of the starter culture addition was also investigated. No significant differences were observed between the cheeses produced using different coagulants in terms of chemical, microbiological and sensory parameters, and proteolysis levels, but the combination of heat treatment and starter culture addition affected most of the attributes. A total of 27 volatile compounds, including acids, alcohols, esters, ketones, and aldehydes, were identified in the cheeses during ripening. Acidic compounds were the most abundant volatiles in cheeses. The raw milk cheeses had the highest sensory scores, while an unpleasantly bitter taste was recorded for the heat-treated and starter-free milk cheeses.

Creating an environment that supports and protects breastfeeding

Creating an environment that supports and protects breastfeeding Many mothers want to breastfeed, but the UK has some of the lowest breastfeeding rates in the world, which are still declining. As many mothers choose to stop breastfeeding in the early weeks, they aren't often ready to do so, and do not receive the support that they really need. Professor Amy Brown stresses the benefits of breastfeeding to tackle this problem for many mothers. In research and collaboration with governments, public health bodies, and infant feeding charities, promoting, protecting and supporting breastfeeding is at the forefront of baby campaigns. Key to these campaigns are getting people to understand breastfeeding and normal baby behaviour, highlighting the importance of breastfeeding for mental health, and calling for greater investment into supporting all types of infant feeding. Human milk is lifesaving for premature babies. When they cannot receive their own mother's breastmilk, specially heat-treated donor milk from other mothers who have been carefully screened can protect their health and development. Recent WHO recommendations are that donor milk should be available for all preterm babies where there is a shortfall of maternal milk.

Supplementation of tomato pomace in lassi (a traditional Indian dairy product)and its effects on physico-chemical, functional attributes and shelf-life of lassi

Utilization of agriculture waste as food additives increased significantly due to their potential health and nutritional attributes. Tomato crop is widely grown across the globe and generates large amount of waste in the form of tomato pomace during the processing of tomato. Dried tomato pomace has a higher shelf-life and easier for food fortification. Lassi is a traditional Indian dairy product consumed as a refreshing beverage during summer. Considering the various health and nutritional benefits of tomato pomace present study was undertaken to supplement tomato pomace in lassi. Tomato pomace powder (TPP) was prepared by tray drying at 55-60 °C for 16-18hrs. Pomace had 16.70% protein, 57.53% crude fibre, and 49.80%2, 2 diphenyl-1-picryl hydroxyl (DPPH) inhibition activity, 311.7mg gallic acid equivalents (GAE)/100g total phenolic content(TPC). Supplementation of tomato pomace was done at different rates of 0.5, 1.0, 1.5, and 2.0% (w/v) of milk during the heating of milk. 1% tomato pomace added lassi had a better sensory score and physico-chemical properties with an overall acceptability score of 7.5. In, addition 1 % tomato pomace lassi had 2.53% fat,2.67% protein, 18.81% total solids, 0.66% ash, 21.81% DPPH inhibition antioxidant activity and 12.37 mg GAE/100 g. Tomato pomace powder added lassi was found stable up to 12 days of storage study while the control sample (without tomato pomace)was unacceptable after 9 days of storage. Lassi supplemented with tomato pomace rich in fibre and antioxidant activity. Utilization of tomato pomace in lassi fortification can be better alternative for tomato processor as lassi consumed very large segment of population.

Inhibitory effect of casein and alpha-lactalbumin on Chryseobacteria spp. isolated from milk and dairy products

In this study, pathogenic and food spoilage bacteria Chryseobacteria spp. were isolated by a new method from 150 samples of raw milk (26/50), heat-treated milk (HTM) (5/50) and butter (2/50). The species with the highest prevalence was C. indologenes (10.67%) followed by C. bovis and C. gleum (4.67% each), and C. bernardetii (2%). The three new strains C. bernardetii, C. gleum, and C. indologenes were named MW703610, MW703611, and MW703612, respectively, with identities ranging from 97.8% to 98.9%. Gene sequencing was performed on some isolates and proved the highest sequence similarity for C. bernardetii WD1 (97.8%), C. gleum WD2 (98.9%) and C. indologenes WD3 (98.9%). Most of the isolated Chryseobacteria spp. showed proteolytic and lipolytic activity. Therefore, casein and alpha-lactalbumin were used as natural antibacterial substances against all isolates. Higher bioactivity against the isolates was obtained using casein rather than the alpha-lactalbumin. Based on these results, casein and alpha-lactalbumin may be promising natural bioactive agents against pathogenic Chryseobacteria spp. Further studies should be done to establish the natural peptide fractions associated with the observed activity.