不同杂交代水牛奶对Mozzarella鲜奶酪品质的影响

本文分析了尼里-拉菲及其不同杂交代水牛奶的理化特性,并研究了以尼里-拉菲及其不同杂交代水牛奶制备的Mozzarella鲜奶酪的理化指标、感官、盐水贮存中的含水率及在2⁶℃冷柜内保存期间p H变化。结果表明,不同杂交代水牛奶的蛋白质、脂肪、总乳固体含量均高于尼里-拉菲,不同杂交代水牛奶制备的Mozzarella鲜奶酪蛋白质含量13%、脂肪含量23%、水分含量59%、出品率20%左右,采用尼杂二代、三代及以上的水牛奶制备的Mozzarella鲜奶酪质量较好,鲜奶酪在2⁶℃的冷柜内保存宜控制在10d内。      

Short communication: Identification and technological characterization of yeast strains isolated from samples of water buffalo Mozzarella cheese

Sixty yeast cultures were isolated from samples of water buffalo Mozzarella, a popular “pasta filata” cheese, originating on 16 farms located in the provinces of Salerno, Caserta, and Frosinone (Italy). Strains were identified by means of 5.8S internal transcribed spacer rDNA PCR-RFLP combined with 26S rRNA gene partial sequencing and characterized for their ability to exert biochemical properties of technological interest. The recorded dominance of fermenting yeasts such as the lactose-fermenting Kluyveromyces marxianus (38.3% of the total isolates) and the galactose-fermenting Saccharomyces cerevisiae (21.6% of the total isolates) suggests that these yeasts contribute to the organoleptic definition of the water buffalo Mozzarella. The speciographic analysis revealed the presence of 7 other species rarely or never reported in a dairy environment belonging to the genera Pichia and Candida, whose role in Mozzarella cheese organoleptic properties need to be further investigated.     

Short communication: Effects of systemic treatment with penethamate hydriodide on udder health and milk yields in dry primiparous Mediterranean buffaloes (Bubalus bubalis)

The effects of penethamate hydriodide (Mamyzin, Boehringer Ingelheim, Ingelheim, Germany) on udder health and milk yields were evaluated in primiparous Mediterranean buffaloes (Bubalus bubalis). An intramuscular administration of 10 million international units was performed in 20 buffaloes at 7 d precalving (treatment group; TG), and 20 animals were enrolled as the control group (CG). Evening milk samplings were performed at 10, 30, and 60 d in milk (DIM). Somatic cell count (SCC) values were evaluated on composite milk samples, whereas bacteriological culture and California Mastitis Test were performed on quarter milk. Daily milk yields were recorded after all milkings. After 60 DIM, composite milk samples from each animal were collected for monthly SCC and bacteriological culture until drying off. Statistically significant differences were found between the prevalence of mastitic quarters in the 2 groups at 10 and 30 DIM, and between the incidence of mastitic animals during the examined period (TG: 4/20, 20% vs. CG: 10/20, 50%). Even though lower and higher values of SCC and milk yields were found in TG during each sampling, statistically significant differences were only found at 30 (SCC) and 60 DIM (milk yields). In our study, the antibiotic administration precalving showed good bactericidal activity against the most common udder-specific pathogens that cause mastitis in primiparous Mediterranean buffaloes, and greater efficacy was observed at 10 and 30 DIM compared with 60 DIM. Given the significant decrease in SCC and increase in yields achieved, use of this antibiotic could be economically beneficial in buffalo breeding.     

Characterization of the major whey proteins from milk of Mediterranean water buffalo (Bubalus bubalis)

In this work, the whey protein fractions from 120 Mediterranean water buffalo individual milks were analysed by microchip electrophoresis (MCE), reverse-phase high-performance liquid chromatography (RP-HPLC) and mass spectrometry (ESI-MS). Validation procedures were carried out for both MCE and HPLC. The chromatographic analysis allowed the complete separation of the whey protein fractions, resulting in a well-defined peak structure; the adopted RP-HPLC and ESI-MS protocols provided identification of β-lactoglobulin (18,266 Da), α-lactoalbumin (14,236 Da) and serum albumin (66,397 Da). The calculated mean concentrations were 4.04 g/l, 2.45 g/l and 0.35 g/l, respectively.     

Short communication: Prediction of milk coagulation and acidity traits in Mediterranean buffalo milk using Fourier-transform mid-infrared spectroscopy

Milk coagulation and acidity traits are important factors to inform the cheesemaking process. Those traits have been deeply studied in bovine milk, whereas scarce information is available for buffalo milk. However, the dairy industry is interested in a method to determine milk coagulation and acidity features quickly and in a cost-effective manner, which could be provided by Fourier-transform mid-infrared (FT-MIR) spectroscopy. The aim of this study was to evaluate the potential of FT-MIR to predict coagulation and acidity traits of Mediterranean buffalo milk. A total of 654 records from 36 herds located in central Italy with information on milk yield, somatic cell score, milk chemical composition, milk acidity [pH, titratable acidity (TA)], and milk coagulation properties (rennet coagulation time, curd firming time, and curd firmness) were available for statistical analysis. Reference measures of milk acidity and coagulation properties were matched with milk spectral information, and FT-MIR prediction models were built using partial least squares regression. The data set was divided into a calibration set (75%) and a validation set (25%). The capacity of FT-MIR spectroscopy to correctly classify milk samples based on their renneting ability was evaluated by a canonical discriminant analysis. Average values for milk coagulation traits were 13.32 min, 3.24 min, and 39.27 mm for rennet coagulation time, curd firming time, and curd firmness, respectively. Milk acidity traits averaged 6.66 (pH) and 7.22 Soxhlet-Henkel degrees/100 mL (TA). All milk coagulation and acidity traits, except for pH, had high variability (17 to 46%). Prediction models of coagulation traits were moderately to scarcely accurate, whereas the coefficients of determination of external validation were 0.76 and 0.66 for pH and TA, respectively. Canonical discriminant analysis indicated that information on milk coagulating ability is present in the MIR spectra, and the model correctly classified as noncoagulating the 91.57 and 67.86% of milk samples in the calibration and validation sets, respectively. In conclusion, our results can be relevant to the dairy industry to classify buffalo milk samples before processing.     

Short communication: Relationships between milk quality and acidification in the production of table Mozzarella without starters

The effect of some quality parameters of the milk (refrigeration time, pH, protein, and fat/protein ratio) on the extent of acidification in the production technology of table Mozzarella without starters was investigated. A screening phase carried out at the laboratory level demonstrated that variations of the milk characteristics require different levels of acidification to keep constant the quality of the cheese. The elaboration of the data collected throughout the successive experimentation on industrial scale allowed us to find a mathematical model to describe the relationships between the pH of the curd at stretching time and the milk characteristics, of which the protein concentration and the refrigeration time play the main roles.     

Short communication: Intra- and inter-individual milk microbiota variability in healthy and infected water buffalo udder quarters

The concept that ruminant mammary gland quarters are anatomically and physiologically unrelated has been recently challenged by immunological evidence. How this interdependence reflects on individual quarter milk microbiota is unknown. The aim of the present study was to cover this gap by investigating the interdependence of quarters among the same mammary gland at the milk microbiota level using next-generation sequencing of the V4–16S rRNA gene. A total of 52 samples were included in this study and classified as healthy or affected by subclinical mastitis. Extraction of DNA, amplification of the V4–16S rRNA gene, and sequencing using Ion Torrent Personal Genome Machine (Thermo Fisher Scientific, Waltham, MA) were carried out. We found that the intra-individual variability was lower than the inter-individual one. The present findings further support at milk microbiota level the hypothesis of the interdependence of quarters, as previously demonstrated following immunological studies, suggesting that individual factors (e.g., immunity, genetics) may have a role in modulating milk microbiota.     

Effects of age and calving season on lactation curves of milk production traits in Italian water buffaloes

Test day (TD) records of milk production traits (milk yield, fat, and protein percentages) of 534 Italian buffalo cows were analyzed with a mixed linear model in order to estimate lactation curves pertaining to different ages at calving and different seasons of calving. Milk yield lactation curves of younger animals were lower than those of older animals until 20 wk from parturition. No effect of age at calving could be observed for fat and protein percentages. Season of calving affected milk yield only in the first phase of lactation, with the lowest production levels for summer calvings; no effect could be observed on fat and protein contents. Average correlations among TD measures within lactation were 0.59, 0.31, and 0.36 for milk yield, fat, and protein percentages, respectively. Five standard linear functions of time were able to reconstruct the average lactation curves. Goodness of fit was satisfactory for all models considered, although only the five-parameter model was flexible enough to fit all the three traits considered with excellent results.     

Short communication: Evaluation of supercritical fluid extraction aids for optimum extraction of nonpolar lipids from buttermilk powder

The milk fat globule membrane, present in buttermilk, contains complex lipids such as phospholipids. Microfiltration coupled with supercritical fluid extraction (SFE) may provide a method of enriching these nutritionally valuable lipids into a novel ingredient. Therefore, SFE as a method for phospholipid enrichment needs to be optimized for lipid removal effectiveness. The role of matrix additions to the buttermilk powder for extraction efficiency was evaluated. Diatomaceous earth (biosilicates), Teflon beads, and physical vibration were tested and shown to reduce total lipid by 86, 78, and 70%, respectively. Four consecutive treatments were shown to exhaust the system; however, similar extraction efficiencies were noted for 1 treatment with biosilicate addition, 2 treatments with physical vibration, or 3 treatments with added Teflon beads. The extracted lipid material consisted of the nonpolar fraction, and protein concentration was observed to increase slightly compared with the control. Although higher lipid extraction was achieved from the powder with addition of diatomaceous earth, a removable aid is ideal for an edible product.     

Short communication: Seroprevalence of paratuberculosis in Italian water buffaloes (Bubalus bubalis) in the region of Campania

Paratuberculosis is a chronic enteric disease affecting virtually all ruminants, but only anecdotal information is currently available about the occurrence of this disease in water buffaloes (Bubalus bubalis). We carried out a survey study aimed at determining the prevalence of paratuberculosis in 2 provinces in the region of Campania, Italy, where about half of all Italian buffaloes are reared. From May 2017 to December 2018, we collected 201,175 individual serum samples from 995 buffalo herds. The sera were collected from animals over 24 mo old and were tested using a commercial ELISA test. The herd-level apparent prevalence result was 54.7%, and the animal-level apparent prevalence was 1.8%. The herd-level true prevalence was estimated using a Bayesian approach, demonstrating a high herd-level prevalence of paratuberculosis in water buffaloes from the Campania area. These findings suggest that the urgent adoption of paratuberculosis herd-control programs for water buffaloes in this area would be beneficial.     

Clinical outcomes and molecular genotyping of Staphylococcus aureus isolated from milk samples of dairy primiparous Mediterranean buffaloes (Bubalus bubalis)

Staphylococcus aureus is one of the most important pathogens causing mastitis in dairy cows and in Mediterranean buffaloes. Genotype B (GTB) is contagious in dairy cows and may occur in up to 87% of cows of a dairy herd. It was the aim of this study to evaluate genotypes present, clinical outcomes, and prevalence of Staph. aureus in milk samples of primiparous Mediterranean dairy buffaloes. Two hundred composite milk samples originating from 40 primiparous buffaloes were collected from May to June 2012, at d 10, 30, 60, 90, and 150 d in milk (DIM) to perform somatic cell counts and bacteriological cultures. Daily milk yields were recorded. Before parturition until 40 to 50 DIM, all primiparous animals were housed separated from the pluriparous animals. Milking was performed in the same milking parlor, but the primiparous animals were milked first. After 50 DIM, the primiparous were mixed with the pluriparous animals, including the milking procedure. Individual quarter samples were collected from each animal, and aliquots of 1 mL were mixed and used for molecular identification and genotyping of Staph. aureus. The identification of Staph. aureus was performed verifying the presence of nuc gene by nuc gene PCR. All the nuc-positive isolates were subjected to genotype analysis by means of PCR amplification of the 16S-23S rRNA intergenic spacer region and analyzed by a miniaturized electrophoresis system. Of all 200 composite samples, 41 (20.5%) were positive for Staph. aureus, and no genotype other than GTB was identified. The prevalence of samples positive for Staph. aureus was 0% at 10 DIM and increased to a maximum of 22/40 (55%) at 90 DIM. During the period of interest, 14 buffaloes tested positive for Staph. aureus once, 6 were positive twice, and 5 were positive 3 times, whereas 15 animals were negative at every sampling. At 90 and 150 DIM, 7 (17.5%) and 3 buffaloes (7.5%), respectively, showed clinical mastitis (CM), and only 1 (2.5%) showed CM at both samplings. At 60, 90, and 150 DIM, 1 buffalo was found with subclinical mastitis at each sampling. At 30, 60, 90, and 150 DIM, 2.5 (1/40), 22.5 (9/40), 35 (14/40), and 10% (4/40) were considered affected by intramammary infection, respectively. Buffaloes with CM caused by Staph. aureus had statistically significantly higher mean somatic cell count values (6.06 ± 0.29, Log₁₀ cells/mL ± standard deviation) and statistically significantly lower mean daily milk yields (7.15 ± 1.49, liters/animal per day) than healthy animals (4.69 ± 0.23 and 13.87 ± 2.64, respectively), buffaloes with IMI (4.82 ± 0.23 and 11.16 ± 1.80, respectively), or with subclinical mastitis (5.47 ± 0.10 and 10.33 ± 0.68, respectively). Based on our knowledge, this is the first time that Staph. aureus GTB has been identified in milk samples of dairy Mediterranean buffaloes.     

Short communication: Antiviral activity of subcritical water extract of Brassica juncea against influenza virus A/H1N1 in nonfat milk

Subcritical water extract (SWE) of Brassica juncea was studied for antiviral effects against influenza virus A/H1N1 and for the possibility of application as a nonfat milk supplement for use as an “antiviral food.” At maximum nontoxic concentrations, SWE had higher antiviral activity against influenza virus A/H1N1 than n-hexane, ethanol, or hot water (80°C) extracts. Addition of 0.5 mg/mL of B. juncea SWE to culture medium led to 50.35% cell viability (% antiviral activity) for Madin-Darby canine kidney cells infected with influenza virus A/H1N1. Nonfat milk supplemented with 0.28 mg/mL of B. juncea SWE showed 39.62% antiviral activity against influenza virus A/H1N1. Thus, the use of B. juncea SWE as a food supplement might aid in protection from influenza viral infection.     

Detection of cows' milk in ewes' milk and cheese by a sandwich enzyme-linked immunosorbent assay (ELISA)

A sandwich enzyme-linked immunosorbent assay (ELISA) has been successfully developed for the detection of defined amounts of cows' milk in ewes' milk and cheese. Polyclonal antibodies were raised in goats against bovine caseins (BC). The resultant antibodies were recovered from the crude antiserum by ammonium sulphate precipitation and further purified by immunoatisorption of the cross-reacting antibodies onto columns containing immobilised ovine, caprine and bovine caseins, followed by elution of the bovine caseins specific antibodies (anti-BC) from the column containing the bovine caseins. The anti-BC bound to the wells of a microtitre plate were used to capture the BC from milk and cheese mixtures. Further immunorecognition of the captured proteins was attained with the same specific antibodies conjugated to biotin. ExtrAvidin-peroxidase was used to detect biotinylated antibodies bound to their specific antigens. Subsequent enzymic conversion of substrate gave clear absorbance differences when assaying mixtures of ewes' milk and cheese containing variable amounts of cows' milk.     

Short communication: Effects of milk fat depression induced by a dietary supplement containing trans-10, cis-12 conjugated linoleic acid on properties of semi-hard goat cheese

Dietary supplements of conjugated linoleic acid (CLA) containing trans-10, cis-12 CLA reduce milk fat synthesis in lactating goats. This study investigated effects of milk fat depression induced by dietary CLA supplements on the properties of semi-hard goat cheese. Thirty Alpine does were randomly assigned to 1 of 3 groups and fed diets with lipid-encapsulated CLA that provided trans-10, cis-12 CLA at 0 (control), 3 (CLA-1), and 6 g/d (CLA-2). The experiment was a 3 × 3 Latin square design. Periods were 2 wk in length, each separated by 2-wk periods without CLA supplements. Bulk milk was collected on d 3 and 13 of each of 3 periods for cheese manufacture. The largest decrease (23.2%) in milk fat content, induced by the high dosage (6 g/d per doe) of trans-10, cis-12 CLA supplementation at d 13 of treatment, resulted in decreases of cheese yield and moisture of 10.2 and 10.0%, respectively. Although CLA supplementation increased the hardness, springiness, and chewiness, and decreased the cohesiveness and adhesiveness of cheeses, no obvious defects were detected and no significant differences were found in sensory scores among cheeses. In conclusion, milk fat depression induced by a dietary CLA supplement containing trans-10, cis-12 CLA resulted in changes of fat-to-protein ratio in cheese milk and consequently affected properties of semi-hard goat cheese.     

利用水牛乳资源优势,开发南方特色乳制品

介绍了我国奶水牛产业的发展状况，水牛乳的理化、加工特性，水牛乳的加工状况，干酪在我国的发展状况，分析了我国南方发展水牛乳干酪的条件、优势和前景，提出了南方发展水牛乳干酪的设想。     

Short communication: Survival of Vaccinia virus in inoculated cheeses during 60-day ripening

Bovine vaccinia is a neglected zoonosis caused by Vaccinia virus (VACV) and has a major economic and public health effect in Brazil. Previous studies showed infectious VACV particles in milk from either experimentally or naturally infected cows and in fresh cheeses prepared with experimentally contaminated milk. Ripening is a process that leads to major changes in the physical and chemical characteristics of cheese, reducing contamination by spoilage, pathogenic microorganisms, or both. However, it is not known if VACV infectious particles persist after the ripening process. To investigate this issue, viral infectivity at different ripening times was studied in cheeses manufactured with milk experimentally contaminated with VACV strain Guarani P2 (GP2). Cheeses were analyzed at 1, 7, 14, 21, 45, and 60 d of ripening at 25°C. Viral DNA was quantified by real-time PCR, and VACV isolation and titration were performed in Vero cells. The whole experiment was repeated 4 times. Analysis of the mean viral DNA quantification and infectivity indicated a reduction of approximately 2 logs along the ripening process; however, infectious viral particles (1.7 × 10² pfu/mL) could still be recovered at d 60 of ripening. These findings indicate that the ripening process reduces VACV infectivity, but it was not able to inactivate completely the viral particles after 60 d.     

Short communication: Genetic parameters of individual fatty acids in milk of Canadian Holsteins

The objective of the present study was to estimate heritabilities of milk fatty acids (FA) and genetic and phenotypic correlations among milk FA and milk production traits in Canadian Holsteins. One morning milk sample was collected from each of 3,185 dairy cows between February and June 2010 from 52 commercial herds enrolled in Valacta (Ste-Anne-de-Bellevue, Quebec, Canada). Individual FA percentages (g/100 g of total FA) were determined for each sample by gas chromatography. After editing the data, 2,573 cows from 46 herds remained. Genetic parameters were estimated using multitrait animal models fitted under REML. The model included fixed effects of age at calving and stage of lactation each nested within parity and random effects of herd-year-season of calving, animal, and residual. The pedigree of animals with data was traced back 5 generations on both the male and female sides to account for relationships among animals. The estimates of heritability for individual FA ranged from 0.01 to 0.39, with standard errors ranging from 0.01 to 0.06. Generally, monounsaturated FA (MUFA) and saturated FA (SFA) showed higher heritability estimates than polyunsaturated FA (PUFA). Overall, SFA were negatively genetically correlated with MUFA and PUFA, whereas genetic correlations between MUFA and PUFA were positive. The SFA showed positive associations with fat yield and fat percentage, whereas unsaturated FA were negatively associated with fat yield and fat percentage. Bovine milk FA composition could be improved through genetic selection, and selection for MUFA or against SFA could alter the bovine milk fat profile in a desirable direction.     

Short communication: Detection of undeclared presence of bovine milk in buffalo yogurt

The authenticity of buffalo (Bubalus bubalis) dairy products is a focal issue, considering the increasing demand for buffalo milk products. Therefore, the aim of this study was to investigate the undeclared presence of bovine (Bos taurus) milk in buffalo yogurt, to understand which risk factors might make the product vulnerable to fraud. Real-time PCR assay showed the undeclared presence of bovine DNA in addition to buffalo DNA in 18 of 72 samples. Given the widespread lack of data on the presence of undeclared milk species in buffalo dairy products, the study provides a significant insight into the incidence of fraud in the buffalo dairy field. The data from this study could help improve the analysis of food safety risks along the buffalo milk supply chain and in the dairy processing industry, perceived as being highly vulnerable to food fraud, and prioritize target areas for food policy making to steer and enforce European food fraud regulations.     

Short communication: Viability of culture organisms in honey-enriched acidophilus-bifidus-thermophilus (ABT)-type fermented camel milk

The aim of this research was to monitor the survival during refrigerated storage of Lactobacillus acidophilus LA-5 (A), Bifidobacterium animalis ssp. lactis BB-12 (B), and Streptococcus thermophilus CHCC 742/2130 (T) in cultured dairy foods made from camel and, for comparison, cow milks supplemented with black locust (Robinia pseudoacacia L.) honey and fermented by an acidophilus-bifidus-thermophilus (ABT)-type culture. Two liters of dromedary camel milk and 2 L of cow milk were heated to 90°C and held for 10 min, then cooled to 40°C. One half of both types of milk was fortified with black locust honey at the rate of 5.0% (wt/vol), whereas the other half was devoid of honey and served as a control. The camel and cow milks with and without honey were subsequently inoculated with ABT-5 culture and were fermented at 37°C until a pH value of 4.6 was reached. Thereafter, the probiotic fermented milks were cooled to 15°C in ice water and were each separated into 18 fractions that were transferred in sterile, tightly capped centrifuge tubes. After 24 h of cooling at 8°C (d 0), the samples were stored at refrigeration temperature (4°C). Three tubes of all 4 products (i.e., fermented camel and cow milks with and without honey) were taken at each sampling time (i.e., following 0, 7, 14, 21, 28, and 35 d of storage), and the counts of characteristic microorganisms and those of certain spoilage microbes (yeasts, molds, coliforms, Escherichia coli) were enumerated. The entire experimental program was repeated twice. The results showed that addition of black locust honey at 5% to heat-treated camel and cow milks did not influence the growth and survival of starter streptococci during production and subsequent refrigerated storage of fermented ABT milks. In contrast, honey improved retention of viability of B. animalis ssp. lactis BB-12 in the camel milk-based product during storage at 4°C up to 5 wk. No spoilage organisms were detected in any of the samples tested in this study. In conclusion, supplementation of cultured dairy foods, especially those made from camel milk, with honey is recommended because honey is a healthy natural sweetener with a variety of beneficial microbiological, nutritional, and sensory properties.     

Short communication: Monitoring the presence of perfluoroalkyl substances in Italian cow milk

Perfluoroalkyl substances (PFAS) are fully fluorinated compounds widely used during the last 60 yr in the production of multiple industrial and consumer applications, such as food packaging, nonstick cookware, cleaning agents, and many more. These emerging contaminants have recently become of concern for human health because of their potential negative effects. The risk of exposure to PFAS for humans is mainly related to diet, and the increasing interest in food safety has led the European Commission to call Member States to monitor these contaminants in food matrices. The purpose of the present work was to perform the first monitoring on the presence of perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA), the 2 main and most widely investigated molecules of this family, in cow milk commercially available in Italy. We used an analytical protocol consisting of liquid-liquid extraction followed by 2 purification steps through solid-phase extraction cartridges and injection on an ultra-performance liquid chromatography-tandem mass spectroscopy system. The analysis of 67 samples of different types of cow milk from Italy demonstrated that contamination by PFOS was often present, although at relatively low concentrations (up to 97 ng/L), whereas PFOA was rarely found. On the basis of these results and data reported in the literature on this matrix, milk does not seem to be a major source of PFAS compared with other food categories such as fish and seafood. However, variability among different types of milk must be taken into account, and surveys of milk-derived products would be helpful to better define the risk for consumers.