Food engineering within the dairy sector is an ever developing field of study purely based on the application of engineering principles and concepts to any aspect of dairy product manufacturing and operations. The last 25 years of science and technology devoted to milk and milk products have led to major advances. The purpose of this paper is to review the history and current status of some engineered milk products and to speculate regarding future trends. Much of the advancement has been directed towards production capacity, mechanisation, automation, hygiene within the processing plant, safety, extensions in shelf life, and new product introductions that bring variety and convenience for the consumer. Significant advancements in product quality have been made, many of these arising from improved knowledge of the functional properties of ingredients and their impact on structure and texture. In addition, further improvements focused on energy efficiency and environmental sustainability have been made and will be needed in the future.

Dairy cows can have different degrees of hypocalcaemia around calving. Lowering dietary Ca availability before calving can prevent it. Rice bran, treated for lower rumen degradability of phytic acid can reduce dietary availability of Ca. During 3 periods of 3 weeks, 113 multiparous cows calved in a single close-up group, which was fed first a control diet, then 140 g/kg DM of rumen-protected rice bran, and at last the control diet again. Cows joined the group 3 weeks before expected calving date and left it at calving. Blood samples were taken weekly before parturition and 0, 6 and 12 h after calving, as well as 3 and 28 d in lactation. Serum was analysed for Ca, Mg, and P. Rice bran introduction produced a transient serum Ca decrease. Rice bran feeding reduced serum P and its withdrawal reduced serum Mg. Serum Ca at calving, nadir of serum Ca and serum Ca the first 3 d after calving was higher in cows calving during rice bran feeding. Serum P decreased less and recovered faster after calving when cows had been fed rice bran. Rumen-protected rice bran reduced dietary availability of Ca and induced adaptation of Ca metabolism resulting in improved Ca and P homoeostasis at calving.

The research reported in this Research Communication was undertaken to evaluate the effects of different sources of polyunsaturated fatty acids (PUFA) supplemented in the diet on milk production and milk fatty acid profile of lactating ewes exposed to long term heat stress. The experiment was conducted during summer, involved 32 ewes divided into 4 groups of 8 each, and lasted 6 weeks. The ewes in all groups were fed twice daily and received 1·8 kg/d of oat hay and 1 kg/d of concentrate. Flaxseed group (FS) was supplemented with 250 g/d of whole flaxseed, Ascophyllum nodosum group (AG) was supplemented with 25 g/d of seaweed Ascophyllum nodosum, and the combination group (FS + AG) received both flaxseed and Ascophyllum nodosum supplementation. The control group (CON) was fed with 1 kg/d of pelleted concentrate without PUFA supplementation. Milk samples were collected twice daily per week, and analysed for fat, total protein, casein, and lactose content. At the beginning and then at 2, 4 and 6 week of the experiment each milk sample was analysed for milk fatty acids. Temperature-humidity index (THI) was calculated daily. Supplementation of flaxseed and of the combination of flaxseed and Ascophyllum nodosum increased milk yield. The total content of saturated fatty acids (SFA) in milk decreased for ewes fed FS, followed by FS + AG. On the contrary, monounsaturated fatty acids (MUFA) increased for ewes fed FS and FS + AG. The total n-3 FA was found higher in FS and FS + AG than in AG and CON groups mainly because of the increase in C 18 : 3 n-3 in FS and FS + AG milk. Milk from FS + AG resulted in the highest n-3/n-6 ratio and decreases in atherogenic and thrombogenic indices. The combination of seaweed Ascophyllum nodosum and flaxseed can be suggested as an adequate supplementation to sustain milk production and milk fatty acid profile of sheep during summer season.

Oesophageal tube feeding colostrum is used to ensure sufficient colostrum intake in newborn calves but the impact of tube feeding on animal behaviour is unclear. Therefore the objective of this study was to compare lying behaviour of tube-fed or bottle-fed dairy calves. Calves (n = 37) in 3 groups were offered 3·5 l colostrum 2 h after birth. Calves of the bottle group were fed with a nipple bottle. Calves of the placebo tubing group were tubed for 4 min but no colostrum was given and they were then fed with a nipple bottle. Calves of the tubing group received 3·5 l colostrum via tube feeding. Consumed amount of bottle and placebo tubing calves was recorded. If they refused some of the offered 3·5 l the rest was offered in a second feeding 2 h later. Lying behaviour was measured by data loggers fitted to right hind leg for 3 d. Blood samples were taken 24 h after birth for determination of IgG concentration. The voluntary colostrum intake differed significantly between bottle-fed and placebo tubed calves at first feeding. Considering both colostrum feedings, bottle-fed calves consumed 3·44 ± 0·14 l and placebo tubed calves consumed 3·20 ± 0·38 l colostrum. ImmunoglobulinG intake (255·6 ± 77·5 g IgG), serum IgG concentration 24 h after birth (22·8 ± 6·7 g/l) and total serum protein concentration (6·1 ± 0·6 g/dl) did not differ between groups. None of the calves had a failure of passive transfer. There was no effect of tubing on lying behaviour.

The objectives of this study were to examine heat stress conditions at cow level and to investigate the relationship to the climate conditions at 5 different stationary locations inside a dairy barn. In addition, we compared the climate conditions at cow level between primiparous and multiparous cows for a period of 1 week after regrouping. The temperature-humidity index (THI) differed significantly between all stationary loggers. The lowest THI was measured at the window logger in the experimental stall and the highest THI was measured at the central logger in the experimental stall. The THI at the mobile cow loggers was 2·33 THI points higher than at the stationary loggers. Furthermore, the mean daily THI was higher at the mobile cow loggers than at the stationary loggers on all experimental days. The THI in the experimental pen was 0·44 THI points lower when the experimental cow group was located inside the milking parlour. The THI measured at the mobile cow loggers was 1·63 THI points higher when the experimental cow group was located inside the milking parlour. However, there was no significant difference for all climate variables between primiparous and multiparous cows. These results indicate, there is a wide range of climate conditions inside a dairy barn and especially areas with a great distance to a fresh air supply have an increased risk for the occurrence of heat stress conditions. Furthermore, the heat stress conditions are even higher at cow level and cows not only influence their climatic environment, but also generate microclimates within different locations inside the barn. Therefore climate conditions should be obtained at cow level to evaluate the heat stress conditions that dairy cows are actually exposed to.

The study reported in this Regional Research Communication aimed to analyse the genetic polymorphisms of β-casein in Chinese Holstein cows. β-casein has received considerable research interest in the dairy industry and animal breeding in recent years as a source not only of high quality protein, but also of bioactive peptides that may be linked to health effects. Morever, the polymorphic nature of β-casein and its association with milk production traits, composition, and quality also attracted several efforts in evaluating the allelic distribution of β-casein locus as a potential dairy trait marker. However, few data on beta-casein variants are available for the Chinese Holstein cow. In the present paper, one hundred and thirty three Holstein cows were included in the analysis. Results revealed the presence of 5 variants (A1, A2, A3, B and I), preponderance of the genotype A1A2 (0·353) and superiorities of A1/A2 alleles (0·432 and 0·459, respectively) in the population. Sequence analysis of β-casein gene in the cows showed four nucleotide changes in exon 7. Our study can provide reference and guidance for selection for superior milk for industrial applications and crossbreeding and genetic improvement programmes.

Understanding the milk protein expression profile in different buffalo breeds plays an important role in improving hybrid selection and determining the effects on milk protein synthesis. The aim of this research is to compare the differences in milk protein content, composition and distribution between River buffalo and their crossbreeds for hybrid screening. Four groups of milk samples that included Nili-Ravi (N), Murrah (M), a Nili-Ravi-Murrah crossbreed (M-N), and a crossbreed of river buffalo with local swamp buffalo (C) were collected. The protein composition of the buffalo milk was determined by RP-HPLC. A gel-based proteomic approach consisting of two-dimensional gel electrophoresis coupled with mass spectrometry was utilised for the detailed protein characterisation of milk from different breeds. The results of this analysis showed that the river/swamp buffalo crossbreed (C) displayed the highest content of total protein (4·46%) and κ-casein (11·14%) but the lowest content of α-lactalbumin (6·79%). By selecting 23 different protein spots among the four types of milk that contained the most spots corresponding to κ-casein, β-casein and αs1-casein, correlations between the crossbreeds, protein polymorphism and phosphorylation could be made. The results of this study indicate that crossbreeding a swamp buffalo with a river buffalo has a notable effect on the protein content and composition that may be exploited for producing high-quality raw milk in food technology applications and dairy food production.

Dairy cows grazing pasture and milked using automated milking systems (AMS) have lower milking frequencies than indoor fed cows milked using AMS. Therefore, milk recording intervals used for herd testing indoor fed cows may not be suitable for cows on pasture based farms. We hypothesised that accurate standardised 24 h estimates could be determined for AMS herds with milk recording intervals of less than the Gold Standard (48 hs), but that the optimum milk recording interval would depend on the herd average for milking frequency. The Gold Standard protocol was applied on five commercial dairy farms with AMS, between December 2011 and February 2013. From 12 milk recording test periods, involving 2211 cow-test days and 8049 cow milkings, standardised 24 h estimates for milk volume and milk composition were calculated for the Gold Standard protocol and compared with those collected during nine alternative sampling scenarios, including six shorter sampling periods and three in which a fixed number of milk samples per cow were collected. Results infer a 48 h milk recording protocol is unnecessarily long for collecting accurate estimates during milk recording on pasture based AMS farms. Collection of two milk samples only per cow was optimal in terms of high concordance correlation coefficients for milk volume and components and a low proportion of missed cow-test days. Further research is required to determine the effects of diurnal variations in milk composition on standardised 24 h estimates for milk volume and components, before a protocol based on a fixed number of samples could be considered. Based on the results of this study New Zealand have adopted a split protocol for herd testing based on the average milking frequency for the herd (NZ Herd Test Standard 8100:2015).

The aim of this study was to compare seven non-linear mathematical models (Brody, Wood, Dhanoa, Sikka, Nelder, Rook and Dijkstra) to examine their efficiency in describing the lactation curves for milk fat to protein ratio (FPR) in Iranian buffaloes. Data were 43 818 test-day records for FPR from the first three lactations of Iranian buffaloes which were collected on 523 dairy herds in the period from 1996 to 2012 by the Animal Breeding Center of Iran. Each model was fitted to monthly FPR records of buffaloes using the non-linear mixed model procedure (PROC NLMIXED) in SAS and the parameters were estimated. The models were tested for goodness of fit using Akaike's information criterion (AIC), Bayesian information criterion (BIC) and log maximum likelihood (−2 Log L). The Nelder and Sikka mixed models provided the best fit of lactation curve for FPR in the first and second lactations of Iranian buffaloes, respectively. However, Wood, Dhanoa and Sikka mixed models provided the best fit of lactation curve for FPR in the third parity buffaloes. Evaluation of first, second and third lactation features showed that all models, except for Dijkstra model in the third lactation, under-predicted test time at which daily FPR was minimum. On the other hand, minimum FPR was over-predicted by all equations. Evaluation of the different models used in this study indicated that non-linear mixed models were sufficient for fitting test-day FPR records of Iranian buffaloes.

This Research Communication reports interferences related to the administration of ivermectin in lactating dairy goats on the response of microbial tests for screening antibiotics in milk. Twenty-eight Murciano-Granadina goats, naturally infested with Sarcoptes scabiei var. caprae, were treated with a subcutaneous injection of ivermectin (200 µg/kg b.w.). To prevent re-infestation, a second dose was applied 7 d later. Individual milk samples were collected, daily, up to 15 d post-treatment. Milk samples were analysed by microbial inhibitor tests (BRT MRL, Delvotest SP-NT MCS and Eclipse 100) and ivermectin residues were quantified by HPLC. A large number of positive results were obtained for all microbial tests, especially on the first day after treatment (BRT MRL = 46·4%; Delvotest SP-NT MCS = 14·3%; and Eclipse 100 = 17·8%). However, the highest concentration of drug residues in milk (24·3 ng/ml) was detected on the tenth day after treatment, when positive outcomes were relatively lower (BRT MRL = 17·8%; Delvotest SP-NT MCS = 10·7%; and Eclipse 100 = 7·4%). Results herein suggest that factors related to the ivermectin treatment other than drug residues in milk, or alterations produced by the parasitic disease itself affecting the immune response of animals, could be the cause of false-positive results in microbial tests. It can be concluded that the application of ivermectin in dairy goats infested with sarcoptes mange during lactation produces persistent drug residues in milk, and could also cause false-positive results in microbial inhibitor tests for screening antibiotics.

The objective of this study was to compare the prediction efficiency of IgG concentration in bovine colostrum by NIRS, using liquid and dried (Dry-Extract Spectroscopy for Infrared Reflectance, DESIR) samples by transflectance and reflectance modes, respectively. Colostrum samples (157), obtained from 2 commercial Holstein dairy farms, were collected within the first hour after calving and kept at −20 °C until analysis. After thawing and homogenisation, a subsample of 500 mg of liquid colostrum was placed in an aluminium mirror transflectance cell (0·1 mm path length), in duplicate, to collect the spectrum. A glass fiber filter disc was infused with another subsample of 500 mg of colostrum, in duplicate, and dried in a forced-air oven at 60 °C for 20 min. The samples were placed in cells for dry samples to collect the spectra. The spectra in the VIS-NIR region (400–2500 nm) were obtained with a NIRSystems 6500 monochromator. Mathematical treatments, scatter correction treatments and number of cross-validation groups were tested to obtain prediction equations for both techniques. Reference analysis for IgG content was performed by radial immunodiffusion. The DESIR technique showed a higher variation in the spectral regions associated with water absorption bands, compared with liquid samples. The best equation for transflectance method (liquid samples) obtained a higher coefficient of determination for calibration (0·95 vs. 0·94, respectively) and cross validation (0·94 vs. 0·91, respectively), and a lower error of cross validation (9·03 vs. 11·5, respectively) than the best equation for reflectance method (DESIR samples). In final, both methods showed excellent capacity for quantitative analysis, with residual predictive deviations above 3. It is concluded that, regarding accuracy of prediction and time for obtaining results of IgG from bovine colostrum, NIRS analysis of liquid samples (transflectance) is recommended over dried samples (DESIR technique by reflectance).

The periparturient period is one of the most critical periods in the productive life of a dairy cow, and is the period when dairy cows are most susceptible to developing new intramammary infections (IMI) leading to mastitis. Acute phase proteins (APP) such as haptoglobin (Hp), mammary associated serum amyloid A3 (M-SAA3) and C-reactive protein (CRP) have been detected in milk during mastitis but their presence in colostrum and milk in the immediate postpartum period has had limited investigation. The hypothesis was tested that APP are a constituent of colostrum and milk during this period. Enzyme linked immunosorbent assays (ELISAs) were used to determine each APP's concentration in colostrum and milk collected daily from the first to tenth day following calving in 22 Holstein-Friesian dairy cows. Haptoglobin was assessed in individual quarters and composite milk samples while M-SAA3 and CRP concentration were determined in composite milk samples. Change in Hp in relation to the high abundance proteins during the transition from colostrum to milk were evaluated by 1 and 2 dimension electrophoresis and western blot. In 80% of the cows all APPs were detected in colostrum on the first day following parturition at moderately high levels but gradually decreased to minimal values in the milk by the 6th day after calving. The remaining cows (20%) showed different patterns in the daily milk APP concentrations and when an elevated level is detected could reflect the presence of IMI. Demonstration that APP are present in colostrum and milk following parturition but fall to low levels within 4 days means that elevated APP after this time could be biomarkers of post parturient mastitis allowing early intervention to reduce disease on dairy farms.

The urokinase-plasminogen activator (u-PA), its receptor (u-PAR) and the inhibitors of u-PA (PAI-1 and PAI-2) provide a multi-molecular system in leucocytes that exerts pleiotropic functions influencing the development of inflammatory and immune responses. The objective of the present study was to examine the ability of water soluble extracts (WSE) obtained from traditional Greek yoghurt made from bovine or ovine milk to modulate the expression of u-PA, u-PAR, PAI-1 and PAI-2 in ovine monocytes and neutrophils. WSE were obtained from 8 commercial traditional type Greek yoghurts made from ovine or bovine milk. WSE upregulated the expression of all 4 u-PA related genes in monocytes but the upregulation was much higher in the PAI-1 (10-fold) than in u-PA and u-PAR (3–4 fold) thus, shifting the system towards inhibition. In line with this observation, WSE reduced total and membrane-bound u-PA activity in monocytes. In neutrophils, WSE caused small (50–60%) but significant (P < 0·05) reductions in expression of u-PAR and PAI-2 but had no effect on expression of u-PA, PAI-1 and on total cell-associated and membrane-bound u-PA activity. WSE from yoghurts made from bovine or ovine milk were essentially equally effective in affecting the u-PA system except for the u-PAR gene in ovine neutrophils that was affected (reduced) by the ovine and not the bovine WSE. In conclusion, peptides present in WSE modulated the expression of u-PA related genes but the effect was much more prominent in monocytes than in neutrophils.

Colostrum and milk feeding are key factors for the newborn ruminant survival, affecting the future performance of the animal. Nowadays, there is an increasing interest in the potential of feeding newborn ruminants (mainly goat kids and lambs) with colostrum and milk from other more productive ruminant species (mainly cows). Although some studies regarding differences between colostrum and milk from these three species have been performed, herein we conduct for the first time a comparison using a proteomics 2-Dimensional Electrophoresis gel-based approach between these three ruminant species. In this study colostrum and milk samples from six Holstein cows, six Canarian sheep and six Majorera goats were used to determine the chemical composition, immunoglobulin G (IgG) and M (IgM) concentrations and proteomics profiles. Results showed that in general sheep colostrum and milk contained higher fat, protein and lactose percentages compared to bovine and goat samples. Additionally, no differences in the IgG or IgM concentrations were found among any of the three studied species, with the exception of sheep colostrum that showed the highest IgM concentration. With reference to the proteomics-based approach, some high abundant proteins such as serum albumin precursor, beta-caseins or different immunoglobulins components were found in colostrum, milk or even both. Nevertheless, differences in other proteins with immune function such as serotransferrin or lactoperoxidase were detected. This study shows that despite the similar immunoglobulin concentrations in colostrum and milk from the three studied species, differences in several immune components can be detected when these samples are studied using a proteomics approach. Finally, this study also provides a base for future investigation in colostrum and milk proteomics and metabolomics.

The objective of the study was to investigate the effect of season on the fatty acid and terpene composition in ewe milk. A total of 760 samples of bulk sheep milk were collected during winter (147 samples), spring (314 samples) and summer (299 samples) of 2011, from 90 commercial farms of dairy sheep from the prefecture of Grevena, Greece. Regarding fatty acid composition, summer samples had higher concentrations of α-linolenic acid, cis-9, trans 11- CLA, trans-11, C18 : 1 and PUFAs but lower content of saturated fatty acids particularly C12 : 0, C14 : 0 and C16 : 0. The winter milk had the lowest content of terpenes, in particular sesquiterpenes, compared to spring and summer milk. The terpene profile of milk samples, in all three seasons, revealed the presence of monoterpenes: a-pinene, b-pinene and D-limonene, especially with a higher frequency of appearance in summer. The most common and abundant sesquiterpenes found in milk samples were β-caryophyllene and α-caryophyllene with a higher frequency of appearance in summer. In conclusion, the available pastures in semi-extensive farming systems can contribute to the production of high quality milk.

During the last years the interest in donkey milk has increased significantly mainly because of its compelling functional elements. Even if the composition and nutritional properties of donkey milk are known, its microbiota is less studied. This Research Communication aimed to provide a comprehensive characterisation of the lactic acid bacteria in raw donkey milk. RAPD-PCR assay combined with 16S rDNA sequencing analysis were used to describe the microbial diversity of several donkey farms in the North West part of Italy. The more frequently detected species were: Lactobacillus paracasei, Lactococcus lactis and Carnobacterium maltaromaticum. Less abundant genera were Leuconostoc, Enterococcus and Streptococcus. The yeast Kluyveromyces marxianus was also isolated. The bacterial and biotype distribution notably diverged among the farms. Several of the found species, not previously detected in donkey milk, could have an important probiotic activity and biotechnological potential. This study represents an important insight to the ample diversity of the microorganisms present in the highly selective ecosystem of raw donkey milk.

Oxidation-reduction potential (Eh) is a fundamental physicochemical property of lactic acid bacteria that determines the microenvironment during the cheese manufacture and ripening. For this reason the Eh is of growing interest in dairy research and the dairy industry. The objective of the study was to perform a comprehensive study on the reduction activity of wild lactic acid bacteria strains collected in different periods (from 1960 to 2012) from Italian dairy products. A total of 709 strains belonging to Lactococcus lactis, Enterococcus durans, E. faecium, E. faecalis and Streptococcus thermophilus species were studied for their reduction activity in milk. Kinetics of milk reduction were characterised by the minimum redox potential (Eh7) and time of reaching Eh7 (tmin), the maximum difference between two measures (Δmax) and the time at which these maximum differences occurred (t*). Broad diversity in kinetic parameters was observed at both species and strain levels. E. faecalis and L. lactis resulted to be the most reducing species, while S. thermophilus was characterised by the lowest reducing power while the greatest heterogeneity was pointed out among E. durans and E. faecium strains. Considering the period of collection (1960–2012) we observed that the more recently isolated strains generally showed less reducing activity. This trend was particularly evident for the species E. durans, E. faecium and L. lactis while an opposite trend was observed in E. faecalis species. Data reported in this research provide new information for a deeper understanding of redox potential changes during milk fermentation due to bacterial growth. Gain knowledge of the redox potential of the LAB cultures could allow a better control and standardisation of cheesemaking process.

Physical properties of lactose appeared influenced by presence of lactic acid in the system. Some other components such as Ca may further attenuate lactose behaviour and impact its phase transition. A model-based study was thus implemented with varying concentrations of Ca (0·12, 0·072 or 0·035% w/w) and lactic acid (0·05, 0·2, 0·4 or 1% w/w) in establishing the effects of these two main acid whey constituents on lactose phase behaviour. Concentrated solutions (50% w/w) containing lactose, lactic acid and Ca were analysed for thermal behaviour and structural changes by Differential Scanning Colorimetry (DSC) and Fourier Transform Infrared Spectroscopy (FTIR), respectively. Presence of 1% (w/w) lactic acid and 0·12% (w/w) Ca in lactose solution significantly increased the evaporation enthalpy of water, delayed and increased the energy required for lactose crystallisation as compared to pure lactose. FTIR analysis indicated a strong hydration layer surrounding lactose molecules, restricting water mobility and/or inducing structural changes of lactose, hindering its crystallisation. The formation of calcium lactate, which restricts the diffusion of lactose molecules, is also partly responsible. It appears that Ca removal from acid whey may be a necessary step in improving the processability of acid whey.

The enzymatic hydrolysis of cheese whey was optimised using the enzymes iZyme, Alcalase or Flavourzyme under different conditions. Hydrolysates supplemented with commercial nutrients were evaluated as fermentation broths to produce DL-3-Phenyllactic acid (PLA) from phenylalanine (Phe) by Lactobacillus plantarum CECT-221. Optimised hydrolysates were obtained using Flavourzyme at 50 °C and 100 rpm during 12 h, and assayed in 250 ml Erlenemyer flasks using different proportions of vinasses as economic nutrient. The process was then scaled up using a 2 litres Bioreactor working under the continuous modality. Under the intermediate dilution rate of 0·0207 h−1 0·81 ± 0·026 mM of PLA and 38·8 ± 3·253 g/l of lactic acid were produced. A final evaluation revealed that lactic acid, and bacteriocins exerted the highest inhibitory effect among the extracted components of cell-free supernatants.