Dornic Acidity Research Articles

Impact of breeding system transition on camel milk caseins

To enhance camel milk production, some breeders have transitioned from extensive to semi‐intensive breeding systems. This study investigates the effects of this transition on casein fractions by analyzing milk samples of targeted breeding. Various parameters, such as pH, Dornic acidity, dry matter, ash, total proteins, whey proteins, and caseins, were examined. The results revealed that semi‐intensive camel milk exhibited increased acidity and lower mineral content, while demonstrating significant elevations in total proteins, whey proteins, and particularly caseins. Transition to semi‐intensive system increased κ, β, and αs1‐caseins levels by 0.44, 4.85, and 1.81 g/L, respectively, as observed after FPLC, SDS‐PAGE, and MALDI‐ToF characterization.

Effect of Shelf Life on Physicochemical and Biochemical Parameters of Camel Milk

Background: Animal feed, environmental conditions and the lactation period are the main factors affecting the composition of camel milk. Methods: In this study, samples from eight (8) camels were collected according to hygiene standards to determine the physico-chemical and biochemical parameters of milk during storage at ambient temperature. pH, titratable acidity, density, total dry matter, ash, fat, protein and vitamin C were determined. Result: The results of the physico-chemical analyses indicate a pH of 5.98±0.30, a titratable acidity of 17.51±1.35°D and a density of 1.01±0.02 after 24 hours of storage at ambient temperature. At the same time, biochemical analyses show an ash content of 7±0.58 g/l, a fat content of 50.09±5.97 g/l and a protein content of 2.31±0.21%. The total dry matter content of camel milk is 129.27±11.31 g/l. The vitamin C content is 41.89±4.51 mg/l. Monitoring of the pH changes of camel milk during storage at room temperature (22±6°C) showed low acidification of camel milk after 24 storage, confirmed by the statistical study which revealed a non-significant difference in pH (p greater than 0.41). While after 24 hours, the differences are significant for pH, dornic acidity and vitamin C content (p less than 0.0001). The remaining ingredients (dry matter, fat, ash) experienced a non-significant progressive decrease (p greater than 0.05). A still non-significant decrease in protein content occurred during the first two days of storage. From the second day, the difference became significant (p less than 0.001). The study of density variation showed a slight non-significant increase (p greater than 0.15) over time. These results have allowed us to confirm that the analyzed camel milk, has a number of particularities in its chemical and physical composition, which prolongs its shelf life.

Impact of a feed additive (acidifier and toxin-binder) in milk production in dairy cattle

Dairy cow feeding plays an important role in milk production. The present study was conducted to evaluate the effect of a feed additive (association of acidifier and mycotoxin binder) on milk production in dairy cattle. For this purpose, 22 cows belonging to three breeds (Montbeliard, Holstein, and Flekveih) were used. The cows were divided into two groups; a control group with seven cows and an experimental group with 15 animals. The results showed that the additive had a positive effect on milk production (23.14±5.87 litres for the experimental group vs 18.00±6.90 litres for the control). The additive also had a good effect on the percentage of sub-clinical mastitis: the Californian Mastitis Test (CMT) carried out at monthly intervals showed a clear improvement in the udder health of females in the experiment with 13 positive samples in the first test for nine cows (with four affected teats) and 10 positive samples for the second test in three cows (with three affected teats). Moreover, statistical tests revealed a significant difference in the mean fat content (35 g/L vs 23.86 g/L, respectively) while the average Faeces Consistency Score and Dornic acidity was lower in the experimental group compared to the control (2.23 vs 3.21 and 13.83 vs 16.14, respectively). These results show the importance of incorporating the feed additive into the diet of dairy cows and the need to implement an extension programme and zootechnical supervision of all actors in the sector to ensure the quality of milk production and the performance of dairy cows.

Microbiological and Physicochemical Quality of Raw Milk Marketed in the City of Pala in Chad

Milk is a food with high nutritional value. Its importance results from its richness in water, proteins, lipids, minerals and vitamins. The objective of this study was to evaluate the physico-chemical and microbiological quality of raw cow milk marketed in Pala, Chad. A total of thirty (30) samples were collected. The standard microbiology technique was used to enumerate and test for total aerobic mesophilic flora (TAMF), Escherichia coli, Staphylococcus, yeasts and molds, and Salmonella spp. Dornic acidity content was also assessed. TAMF, E.coli, Staphylococcus, yeast & molds were dissatisfied with the quality in the proportions of 20%, 17%, 83.3% and 7% respectively. Salmonella was totally absent in all samples. The Dornic acidity was high in all samples with a value between 22 and 30°D. In view of these results, raw milk has an acceptable hygienic quality despite the low proportions of dissatisfaction with the quality observed. Efforts to raise awareness of hygiene measures must be made in the milk sector in order to restore its expected safe quality.

Nutritional composition of human milk and its association with maternal and perinatal factors.

The objective of this study was to evaluate the influence of maternal and perinatal factors on the nutritional composition of human milk. A cross-sectional study was conducted between November 2018 and January 2020, with 181 donors selected in Tertiary Health Units of the Unified Health System - from one collection station and five Human Milk Banks. Data were collected through a standardized questionnaire. To be fit to be a donor in a Human Milk Banks and produce mature milk were the eligibility criteria to participate in the study. We excluded milk samples with Dornic acidity above 8° D. The dependent variables were the macronutrients of human milk (i.e., carbohydrates, proteins, lipids, and total energy), that were analyzed using spectroscopy with the Miris Human Milk Analyzer™. The maternal and perinatal factors were the independent variables. Women with pre-gestational obesity and gestational weight gain above the recommendation showed a lower protein concentration compared to eutrophic women (median=0.8, interquartile range (IQR): 0.7-0.9 vs. median=0.8, and IQR: 0.8-1.0) and those with adequate gestational weight gain (median=0.8, IQR: 0.7-0.9 vs. median=0.9, and IQR: 0.8-1.0), respectively. The other analyzed factors (i.e., maternal habits, comorbidities, and perinatal factors) were not associated with the nutritional composition of human milk. The assessment of factors associated with the nutritional composition of human milk is extremely important to assist postpartum care. Pre-gestational obesity and inadequate gestational weight gain were the only factors statistically associated with the nutritional composition of human milk as they impacted its protein content.

Baseline composition and microbial quality assessment of raw milk from small ruminants and Maghrebi camels in the oasis area of Tunisia.

The milk quality and characteristics of the local Gharbi sheep and autochthonous goat population were studied and compared to those of the local Maghrebi camel. Milk samples from 378 lactating animals raised in the Tunisian oasis region were obtained and processed for various physicochemical compositions (pH, density, acidity, dry matter, fat, protein, lactose, casein, ash, and casein-protein ratio), mineral concentrations (Ca, P, Na, and K), and bacteriological properties (total mesophilic aerobic bacteria (TMAB), total coliform count (TCC), lactic acid bacteria (LAB), sulfite-reducing Clostridium (CSR), yeast and molds (Y/M), Staphylococcus aureus (S. aureus), Escherichia coli (E. coli), and Salmonella) using standard methods. Milk from sheep breeds had a higher average of all physical parameters (pH, density, and dornic acidity) than milk from goat species. The sheep population produced milk with a similar pH to the camel population, but with a higher density and acidity content. The pH and acidity were higher in Neggas than in goat species, while density was similar in both. For chemical composition, the results showed significant heterogeneity in milk content across all species. Except for the casein-protein ratio, which favors goat species, the analysis indicates that sheep species were superior to populations of goats and camels in all chemical compositions. The present results showed considerable variation in the mineral content of milk from different species. The levels of calcium and phosphorus are higher in sheep than in goat and camel milk. Compared to small ruminants, milk from camels is the richest in Na and K. Additionally, more calcium is present in the milk of camels than that of goats. Goat milk, the lowest in Ca and Na, contains more P than camel milk and more K than sheep's milk on average. The poorest microbial quality was that of camel milk for all bacterial counts. Based on TMAB, TCC, and E. coli counts, the microbiological quality of goat milk was higher than that of ovine milk, while ovine milk had better quality based on LAB, Y/M, and S. aureus values. For Escherichia coli and Staphylococcus aureus, there were no significant variations between the species studied. Results showed that all milk samples studied were completely free of two dangerous pathogens, Salmonella and sulfite-reducing Clostridium. The bacteriological quality of small ruminant's milk was acceptable and met the regulatory limits set by Tunisian dairy legislation. Regarding camel milk, the microbial analysis revealed poor quality that exceeds standard criteria.

Unveiling unstable non-acid incidence in Holstein cows fed with corn silage or sugarcane.

We aimed to evaluate the incidence of unstable non-acid milk (UNAM) in cows fed either sugarcane or corn silage. Second, we aimed to evaluate the effect of daily variation (d 1 to 4) and alcohol grades (72, 78, and 80%) on UNAM incidence. The experiment was conducted as a split-plot crossover design, with 2 periods and 2 roughage types (sugarcane or corn silage). Thirteen multiparous Holstein cows with an average of 281 ± 29 d in milk were randomly distributed into 2 diets. Individual blood (analysis of total proteins, albumin, urea, calcium, phosphorus, magnesium, iron, chloride, glucose, and lactate) and milk samples (analysis of protein, fat, lactose and total solids, somatic cell count, and characterization of the protein profile) were collected during the last 4 d of each period. For UNAM identification, the alcohol test was conducted in milk samples at 4°C; specifically, if the sample presented the formation of clots, this would be noted as positive for UNAM. In addition, the Dornic acidity analysis was performed in the same samples to evaluate the true milk acidity. The use of sugarcane and higher degrees of alcohol were associated with increased UNAM. We observed no daily variation in UNAM. Nevertheless, we found no roughage type effect on the variables most commonly associated with UNAM, such as changes in salts in the casein micelle and, consequently, the zeta potential and the κ-casein (CN) fraction. The Pearson correlation analysis showed that the zeta potential and the concentrations of αS2-CN, blood ionic calcium, lactate, and glucose increased as the incidence of UNAM increased, showing a positive correlation among these variables. In contrast, the concentrations of lactose, phosphorus, and potassium decreased as UNAM increased, presenting a negative correlation. This study brought important discoveries to unveil why cows manifest UNAM. For instance, higher alcohol grades and cows fed with sugarcane had increased the incidence of UNAM. Additionally, animals with a higher incidence of UNAM (sugarcane-fed cows) were related to increased ionic calcium and glucose and changes in milk protein profile, with lower levels of BSA, β-CN, and α-lactalbumin and greater αS1-CN content, all of which were correlated with UNAM. Nonetheless, this trial also provides evidence for the need for further studies to better understand the physiological mechanisms that directly affect the stability of milk protein.

Effects of pasteurization and high-pressure processing on the fatty acids, triacylglycerol profile, Dornic acidity, and macronutrients in mature human milk

The effects of high-pressure processing (HPP; 300, 400, 500 and 600 MPa for 5 min) compared to Holder pasteurization treatments on the macronutrients, acidity in Dornic, total coliforms, fatty acids (FA) composition, and the triacylglycerols (TAG) profile of mature human milk (HM) were evaluated. The results showed that both processes eliminated the microorganisms present, and the concentration of macronutrients and Dornic acidity did not show significant differences in processes. A total of 34 FAs were identified by gas chromatography with flame ionization detector, with palmitic and oleic acids having the highest concentrations. Regarding the TAG profile determined by direct infusion by electrospray ionization mass spectrometry, TAG PLO (P: palmitic acid; L: linoleic acid; and O: oleic acid) was the one with the highest estimated concentration (6.52–7.27%). The evaluation of hierarchical clustering analysis results suggests that processing with lower pressures was more beneficial for HM due to the similarity between the intensities of the TAGs identified in each sample and the control HM sample. Besides, the results obtained on the evaluated components suggested that HPP could be a promising alternative to HoP applied in human milk banks since it maintained the characteristics of HM and is faster than HoP.

Characterization of the traditional cheese Adghess produced from cow's milk

In Algeria, milk is traditionally transformed into several forms to allow its preservation, particularly fermented products, among which cheese has been the pride of the culinary tradition for a long time. Adghess is a fresh cheese frequently made in the region, especially in rural areas. Adghess is a product poorly known outside its original geographical area. The objective of this study was to characterize Adghess cheese by determining some of its physicochemical and microbiological characteristics. The characterization was preceded by a survey carried out in Oum El Bouaghi with 50 households in order to determine the production diagram of this cheese. The survey was carried out by means of a questionnaire based on random sampling. Ten samples were collected at the level of five farms located in the region and were analyzed for physicochemical attributes such as pH, total dry extract, total lipids as well as, dornic acidity, and microbial population such as total flora, total and fecal coliforms, Salmonella, Clostridium, yeast, and molds. The results obtained showed that the cheese samples analyzed were acidic (pH and an acidity of 4.4 and 38.4°D, respectively). For the total dry extract of Adghess cheese is 334 g kg-1 with a lipid level of 91 g kg-1, the recorded ash content was 3.8g/kg, while sodium chloride was 2.4g/kg. The microbiological results showed a high content of the total flora (7.8×108cfu g-1): Total coliforms were noted to be present in all the analyzed samples, with the absence of fecal coliforms. Unlike molds, yeasts marked their presence (4.6×102cfu g-1). The microbiological findings revealed a high level of total flora (7.8108 cfu g-1): total coliforms were found to be present in all of the examined samples, although fecal coliforms were not found. Yeasts (4.6 102 cfu g-1) left a trace of their existence, unlike molds. The absence of all the pathogenic microorganisms sought (Salmonella, Clostidium, and molds) made the cheese healthier for consumption. Overall, the hygienic quality of the cheese studied was satisfactory. This work constituted the starting point to launch research on this product in order to preserve the know-how on the one hand and achieve the objective of manufacturing it on artisanal, then industrial scales. Key words: Adghess, characterization, traditional, cheese, microbiological, Oum El Bouaghi, preservation, physicochemical, survey

Assessment of Dornic acidity in breast milk based on storage time in the freezer and place of expression.

Introduction. The degree of Dornic acidity (DA) is an indirect measure of milk contamination and quality. In freshly expressed milk, DA ranges between 1.0 and 4.0 (optimal). If DA is > 8.0 °D, it should be discarded. The correlation between DA in raw breast milk from internal donors (ID) and external donors (ED) based on storage time until pasteurization was assessed. Population and method. Retrospective, analytical study. Results. In 13 203 samples, DA was lower in IDs as of 14 days of storage: 2.92 (95% CI: 2.69-3.15) versus 4.01 (95% CI: 3.94-4.08), with a higher proportion of DA ≤ 4 °D (88% in IDs versus 76% in EDs); odds ratio: 2.30 (95% CI: 1.25-4.24). Conclusion. DA as of 14 days of storage was lower in IDs, with a higher prevalence of DA ≤ 4 °D. No correlation was observed between storage time and DA in ID samples.

Ocorrência de leite instável não ácido (LINA) em propriedades leiteiras no norte do Tocantins

The diagnosis of unstable non-acid milk (UNAM) in Brazil is overlooked due to the lack of information about this problem available to dairy farmers, mainly in the North region of the country. This report describes the occurrence of UNAM in three dairy farms of family farmers in northern Tocantins state, Brazil, who use animal feed based on Urochloa brizantha without mineral supplementation. The animals had been subjected to a poor feeding practice, with low quantity and quality, due to the dry period in the region and inappropriate nutritional management. Fourteen animals that presented alterations in milk characteristics were subjected to 72% alizarol test, California mastitis test, strip cup test, somatic cell count (SCC), boil test, physical-chemical and microbiological analyses, and search for undesirable substances. The time of lactation, udder health, and serum glucose level of animals, and soil and forage quality were also evaluated. The results showed 42% animals diagnosed with mastitis, 21% of them with clinical and 21% with subclinical mastitis; and 78% of animals with samples positive for the alizarol and boil tests, and Dornic acidity between 14° and 18°, characterizing positive cases for UNAM. Only one animal presented SCC above the limit established by the Brazilian legislation. The animals presented undamaged teats and no alteration in glycemia. Changes in nutritional management were recommended and done and the alizarol tests were redone after 14 days, showing all negative results for UNAM. The conclusion is that incorrect nutritional management is the main cause of UNAN in the studied cases.

Nutritional and physicochemical quality of formulations based on colostrum and bovine whey.

The objective of this study was to investigate the nutritional quality of bovine colostrum and whey mixtures. Five whey with bovine colostrum formulations were prepared (90:10; 80:20; 70:30; 60:40 and 50:50 whey:colostrum v:v) to be subjected to low-temperature pasteurization (63°C to 65°C for 30 minutes) and freeze-drying. The samples underwent chemical composition characterization, fatty acid profile analysis, determination of contamination by Enterobacteriaceae, pH, and Dornic acidity measurements before and after vat pasteurization. The amount of protein, fat, total solids, defatted dry extract, Brix and density increased as the bovine colostrum concentration increased. The level of saturated fatty acids and the thrombogenicity and atherogenicity indices reduced, while unsaturated fatty acids increased as the level of added bovine colostrum increased. The low-temperature pasteurization of the formulations was possible and effective, eliminating contamination by Enterobacteriaceae in the samples. Mixing bovine colostrum and whey reduced the colostrum viscosity, allowing a successful pasteurization procedure. Due to colostrum composition, the formulations yielded a higher nutritional value when compared to whey alone. The parameters applied in the formulation of mixtures of bovine colostrum and whey resulted in valuable ingredients for preparing novel dairy products.

Traditional Livestock System and Improvement of Cow’s Hygienic Milk Quality Sold in N’Djamena, Chad

Unlike most Sahelian towns, the production and selling of milk in N’Djamena is generally made in a traditional way and causes a serious hygiene and public health problem. This survey aims to improve the hygienic quality of milk by reducing contamination at critical points in the milk production chain. The approach is based on using suitable, cleaning and disinfection equipment’s of milking, collection and storage. The results showed contamination had significantly decreased by comparing the situation before and after interventions. The average of total mesophilic flora felt from 3106 to 104, total coliforms from 6.8103 to 3.9101; thermotolerant coliforms from 2101 to 0.6101 and Staphylococcus from 1.07102 to 1.5101. The pH increased from 6.55 to 6.6 and the dornic acidity from 20 to 21. The investment cost is 15 FCFA/day in the village with 146 liters of milk sold at 275 FCFA per unit. It is 12 FCFA/day per dairy unit for 324.6 liters sold at 533.33 FCFA per unit. The model for improving the hygienic quality of milk sold in N’Djamena improved the physico-chemical qualities of milk and significantly reduced the rate of microbial contamination. The general hygiene improvement and especially personal hygiene quality was weak because it is very difficult to change traditional behavior, but the boil milk action contributed to reduce the initial contamination.

Safety issues of raw milk: evaluation of bacteriological and physicochemical characteristics of human milk from a bank in a teaching hospital, focusing on Staphylococcus species

ABSTRACTMany infants are nurtured with milk supplied by human banks, whose bacteriological and physical-chemical profiles are a major issue. We investigated the bacteriological and physical-chemical characteristics, as well as genotypic and phenotypic and profiles of Staphylococcus species isolated from 240 samples of breast milk from a bank in a teaching hospital. Dornic acidity of milk revealed that 95.4% (229/240) had acceptable limits (< 8.0 oD). Caloric intake showed a wide variation in cream content (4%), fat (4%) and energy values (559.81 Kcal/L). Staphylococcus (105/186 or 56.5%) and Enterobacter (25/186 or 13.4%) were the most prevalent genera, although other microorganisms were identified, including Klebsiella pneumoniae and Pseudomonas aeruginosa. Amoxicillin/clavulanic acid (125/157 or 79.6%), vancomycin (115/157 or 73.2%), and cephalexin (112/157 or 71.3%) were the most effective antimicrobials. High resistance rates of isolates were found to penicillin G (141/157 or 89.8%), ampicillin (135/157 or 86%), and oxacillin (118/157 or 75.2%). Multidrug resistance to ≥ 3 antimicrobials occurred in 66.2% (123/186) of the isolates. Residues of microbial multiplication inhibitory substances were found in 85% (204/240) of samples. Among the coagulase-positive-CPS and negative-CoNS staphylococci, the mecA gene was detected in 53.3% (8/15) and 75% (30/40), respectively. Genes sea, seb and sec were detected in 20% (3/15) of CPS, while tsst-1 was detected in 13.34% (2/15). In addition, 13.3% (2/15) of S. aureus were toxin-producers. Genes sea, seb and sec were detected in 90% (36/40), 5% (2/40) and 15% (6/40) CoNS, respectively. Enterotoxin production was identified in 5% (2/40) of CoNS. The identification of multidrug-resistant bacteria, staphylococci species toxin-producers harboring methicillin-resistance genes, and residues of microbial multiplication inhibitory substances reinforce the need for a continuous vigilance of milk quality offered to infant consumption by human banks.

Evaluation of the lipid composition of the three lactation phases of raw, pasteurized and lyophilized pasteurized human milk

The aim of this study was to analyze the acidity, fatty acid (FA) composition and the triacylglycerol (TAGs) profile of human milk (HM) from three lactation phases (colostrum, transitional and mature) submitted to different treatments (raw milk, pasteurized, pasteurized in conjunction with lyophilization), in order to verify whether these processes applied to the samples can influence the characteristics of the analyzed components. To carry out the analyzes, the project was approved by the ethics committee and the HM was acquired at the Human Milk Bank (HMB) of the University Hospital of Maringá - HUM (Paraná, Brazil). The acidity analysis was performed using the titratable acidity method in Dornic degrees (ºD), the composition in FAs from Gas Chromatography with Flame Ionization Detector (GC-FID), and the TAGs profile by Mass Spectrometry with Electrospray Ionization source (ESI-MS). From the results obtained, it was possible to observe that the Dornic acidity and the composition in AGs did not undergo significant changes by the Tukey test (p&lt;0.05) and the TAG profile remained similar after the application of the processing, when compared samples of raw HM from their respective phase. Therefore, the pasteurization technique in conjunction with freeze drying can be a promising alternative for HM storage and conservation in HMBs, as it guarantees the preservation of the evaluated components, in addition to reducing the storage volume and facilitating the transport of this HM.

Occurrence ofArcobacter spp. in Brazilian Minas frescal cheese and raw cow milk and its association with microbiological and physicochemical parameters

Some Arcobacter species are considered emerging food-borne pathogens. However, their prevalence in dairy products is not well known. Therefore, the aim of the current research is to know the occurrence of Arcobacter species in Minas frescal cheese and raw cow milk and its potential association with physicochemical and microbiological parameters. Two hundred and one food samples (cheese, n = 98 and milk, n = 103) collected between 2016 and 2017 in São Paulo State, Brazil, were analyzed. Arcobacter was isolated using an enrichment broth with further filtration over Arcobacter agar. Colonies were characterized by ERIC-PCR, m-PCR and PCR-RFLP and, when was necessary, sequencing of 16S rRNA and rpoB genes were also assessed. Additionally, cheese samples were evaluated in relation to total coliform (TC), thermotolerant coliforms (TtC), coagulase positive staphylococci (CoPS) count and moisture. Raw milk samples were assessed for aerobic mesophilic bacteria count, TC, TtC, Dornic acidity, proteins, fats, lactose, defatted dry extract, total solids and somatic cell counts. The occurrence of Arcobacter was 10.2% (10/98) and 16.5% (17/103) in cheese and milk samples, respectively. All isolates were identified as Arcobacter butzleri. On the other hand, Multiple Factorial Analysis showed correlation between the presence of this species and the cheese moisture, while this pathogen was correlated with high counts of mesophilic microorganisms and TC in raw milk. No other evaluated parameter in cheese (TC, CoPS) and milk (TtC, Dornic acidity, proteins, fats, lactose, defatted dry extract, total solids and somatic cell counts) showed significant correlation. To date, this is the first report on A. butzleri in Minas frescal cheese, therefore its presence in dairy products could be considered a potential public health concern.

QUALIDADE FÍSICO-QUÍMICA E MICROBIOLÓGICA DO LEITE BOVINO EM DIFERENTES SISTEMAS DE PRODUÇÃO E ESTAÇÕES DO ANO

Resumo O objetivo deste trabalho foi avaliar a interação entre sistemas produtivos e estações do ano sobre a qualidade do leite bovino. Três propriedades foram avaliadas mensalmente, durante as estações, em quatro graus de especialização dos sistemas de produção: altamente especializado, especializado, semiespecializado e não especializado. Em termos de qualidade do leite, consideraram-se os teores de gordura, proteína, sólidos totais, contagem de células somáticas, contagem bacteriana total, acidez titulável em graus Dornic, densidade, índice crioscópico, estabilidade ao alizarol, potencial de hidrogênio (pH) e teste de redução do azul de metileno. Além destes, devido à sua importância para o rendimento industrial dos produtos lácteos de base proteica, foi realizado o fracionamento da proteína total do leite em equivalente proteico do nitrogênio não proteico, da proteína verdadeira e da caseína. A acidez Dornic foi maior na primavera e no inverno, enquanto os valores mais elevados de contagem de células somáticas foram no verão. Os teores de proteína total e proteína verdadeira foram menores durante o verão e elevaram-se os sólidos totais no outono. Com a diminuição dos níveis de especialização das propriedades rurais, observaram-se aumento na contagem bacteriana total e diminuição do nitrogênio não proteico. A densidade apresentou comportamento inverso ao da gordura, enquanto o potencial de hidrogênio (pH) se expressou de modo antagônico à acidez titulável. Na análise multivariada dos dados, foi possível identificar as combinações entre estratos produtivos e estações do ano que apresentavam a melhor qualidade da proteína do leite. Nesse sentido, todos os arranjos de sistemas de produção com o outono, o sistema altamente especializado no inverno, o semiespecializado no verão e o especializado na primavera tiveram qualidade proteica positiva, destacando-se pelas menores contagens de células somáticas a combinação entre a estação primavera e o sistema semiespecializado de produção.

Food safety and quality of distribution of raw human milk from a University Hospital

ABSTRACT Objective To evaluate the quality of raw human milk distributed in the Neonatal Intensive Care Unit of a University Hospital of the city of São Paulo. Methods A cross-sectional study with raw human milk samples from mothers who attended the Human Milk Collection Station of a University Hospital, analyzed between May 2016 and January 2017, excluding mothers of twins. The quality of the raw human milk was assessed by verifying the presence of dirt, the coloration of the milk, the titratable acidity using the Dornic method, and through its energy content. Kruskal-Wallis and Mann-Whitney tests were used for the analysis of the energy profile and the degree of Dornic acidity, according to the stage of the raw human milk and the gestational age of the child. Results The study was composed of 40 samples of 40 different women, with a mean age of 27 years, an average of 11.8 years of education, most of them were multiparous and with a partner. Regarding milk analysis, 55.0% was classified as colostrum, 27.5% as mature milk and 17.5% as transitional milk. All samples presented negative results for dirt and normal coloration. The mean milk acidity was 3.24º Dornic and most of the samples were classified as hypercaloric energy content. There was no association between the lactation stage and gestational age with the acidity value and energy content. Conclusion The quality of raw human milk distributed in the Neonatal Intensive Care Unit of the institution evaluated was considered adequate and the samples analyzed had a high energy content and excellent Dornic acidity.

Queso de leche de alpaca: una nueva alternativa

El trabajo tuvo como objetivo evaluar la posibilidad de elaborar queso a partir de leche de alpaca. Se determinaron las propiedades fisicoquímicas de la leche, así como el rendimiento, composición química y características sensoriales del queso. La leche se obtuvo por ordeño manual de alpacas madres en inicio de lactación con crías en pie, apartadas 12 horas antes del ordeño. En la leche se analizó la densidad, acidez Dornic, grasa Gerber, y se estimaron los sólidos totales y no grasos de la leche. La composición química del queso se determinó por métodos oficiales de la AOAC, y las características sensoriales del queso a través de la prueba hedónica en escala de 1 a 4 con 100 panelistas. La leche fresca presentó una densidad de 1.0469 ± 0.0025, acidez 16.92 ± 1.74 °D, grasa 4.12 ± 0.08%, proteína 6.34 ± 0.41%, sólidos totales 16.84 ± 0.70%, sólidos no grasos 12.72 ± 0.63% y un rendimiento quesero de 21.6 ± 1.9%. La composición química del queso fue humedad 46.5%, ceniza 18.9%, proteína 41.8%, grasa 24.4% (en materia seca). El queso resultó un producto magro, de textura dura y agradable al consumo.

Influence of feeding on some physicochemical and biochemical characteristics of camel milk (Camelus dromadarius)

Composition of camel milk changes according to the type of farming systems; (i) the traditional system based on the consumption of grassland natural plants and (ii) the “modern” system with feeding based on barley and alfalfa. Among components, we did not reveal any significant effect of farming system on either: pH, density, Dornic acidity, total dry extract, fat-free dry matter content, ash content, total protein content and fat content. However, a significant effect (P &lt;0.05) on the vitamin C content was observed. The concentration being higher in the milk from camels in extensive system than in semi-intensive system. Although the diameter of the fat globules was comparable in both cases, a better dispersion was registered in the milk from the camels in the extensive system. If no difference occurred on the global fatty acid profile (proportion of short/medium/long chain fatty acids), lauric acid (C12: 0) and two fatty acids with 2n + 1 carbon atoms (C15: 0 and C17: 0) were present only in the lipids of milk from camels exclusively fed with Saharan rangelands plants. These results suggested that feeding would have consequences on the characteristics inherent in camel milk and partly responsible for its properties.