HPLC determination of flumethrin, deltamethrin, cypermethrin, and cyhalothrin residues in the milk and blood of lactating dairy cows

A procedure to determine residue concentrations of synthetic pyrethroid insecticides (flumethrin, deltamethrin, cypermethrin and cyhalothrin) in the milk and blood of lactating dairy cows was developed. Extraction was performed with acetonitrile, n-hexane partitioning, and silica gel column cleanup with n-hexane and diethyl ether. Analysis was carried out by high- performance liquid chromatography and ultraviolet detection. Recovery of the four pyrethroids averaged 78 to 91% with a minimum detectable concentration of 0.001 mg/kg. The method was reproducible and sensitive.

The influence of sardine consumption on the omega-3 fatty acid content of mature human milk

Objectives: The purpose of this study was to investigate what effect the ingestion of sardines, rich in omega-3 series polyunsaturated fatty acids, has on the composition of breastmilk. Methods: This was a prospective study of 31 nursing mothers under observation at the Hospital Guilherme Álvaro. Each was given 2 kg of fresh sardines twice with a 15-day interval. Milk was sampled and a 24-hour dietary recall questionnaire was applied on days 0, 15 and 30. Milk was assayed for fatty acid content by gas chromatography. Statistical analysis of the results was performed using nonparametric tests with significance set at p < 0.05. Results: The results demonstrate that the nutritional intake of the nursing mothers was adequate at all three sample points. With regard to the omega-3 series fatty acid content of the breastmilk, it was observed that regular consumption and shorter intervals between ingestion and milk collection resulted in higher concentrations of docosapentaenoic acid and docosahexaenoic acid at 15 and 30 days into the study. Fatty acids from the omega-3 and omega-6 series exhibited a significant correlation, r 2 was 0.58 and 0.59 at 15 and 30 days, respectively. Conclusion: These results suggest that incorporating fish into the diets of nursing mother during lactation, in the form of 100 g of sardines two or three times a week, contributes to an increase in omega-3 series fatty acids. Copyright © 2006 by Sociedade Brasileira de Pediatria.

Simultaneous effects of total solids content, milk base, heat treatment temperature and sample temperature on the rheological properties of plain stirred yogurt

Response surface methodology was used to establish a relationship between total solids content, milk base, heat treatment temperature, and sample temperature, and consistency index, flow behaviour index, and apparent viscosity of plain stirred yogurts. Statistical treatments resulted in developments of mathematical models. All samples presented shear thinning fluid behaviour. The increase of the content of total solids (9.3-22.7 %) and milk base heat treatment temperature (81.6-98.4°C) resulted in a significant increase in consistency index and a decrease in flow behaviour index. Increase in the sample temperature (1.6-18.4°C) caused a decrease in consistency index and increase in flow behaviour index. Apparent viscosity was directly related to the content of total solids. Rheological properties of yogurt were highly dependent on the content of total solids in milk.

β-casein gene polymorphism permits identification of bovine milk mixed with bubaline milk in mozzarella cheese

Mozzarella cheese is traditionally prepared from bubaline (Bubalus bubalis) milk, but product adulteration occurs mainly by addition of or full substitution by bovine milk. The aim of this study was to show the usefulnes of molecular markers to identify the admixture of bovine milk to bubaline milk during the manufacturing process of mozzarella cheese. Samples of mozzarella cheese were produced by adding seven different concentrations of bovine milk: 0%, 1%, 2%, 5%, 8%, 12% and 100%. DNA extracted from somatic cells found in cheese were submitted to PCR-RFLP analysis of casein genes: α-s1-CN - CSN1S1 that encompasses 954 bp from exon VII to intron IX (AluI and HinfI), β-CN - CSN2 including 495 bp of exon VII (Hae III and HinfI), and κ-CN - CSN3, encompassing 373 bp of exon IV (AluI and HindIII). Our results indicate that Hae III-RFLP of CSN2exon VII can be used as a molecular marker to detect the presence of bovine milk in mozzarella cheese. Copyright © 2008, Sociedade Brasileira de Genética.

Use of a new milk-clotting protease from Thermomucor indicae-seudaticae N31 as coagulant and changes during ripening of Prato cheese

Prato cheeses were manufactured using coagulant from Thermomucor indicae-seudaticae N31 or a commercial coagulant. Cheeses were characterised using the following analysis: yield; fat; acidity; moisture; ash; salt; pH; total nitrogen; total protein; NS-pH 4.6/NT100; NS-TCA 12%/NT100; casein electrophoresis; and RP-HPLC. The results were statistically analysed and revealed that the proteolytic indices were not significantly different throughout the 60 days of ripening of cheeses made with either coagulant. Even though there were some quantitative differences in the peptide profile of cheeses, the enzyme from T. indicae-seudaticae N31 was used in the production of good quality Prato cheese without having to change the established technological parameters of the process. © 2011 Elsevier Ltd. All rights reserved.

Effect of Psychrotrophic Growth on the Milk Fat Fraction at Different Temperatures of Storage

The use of cooling, without using adequate hygienic practices in primary milk production, allows for the growth of psychrotrophic microorganisms that produce the thermoresistant lipases that give milk a rancid flavor. This study aimed to verify how the variation in temperature influences the lipolytic metabolism of the psychrotrophic organisms. Samples of raw milk were collected and submitted to laboratorial analysis as follows: psychrotrophic bacteria count, lipolytic bacteria count, and free fatty acids dosage. Each sample was divided into 3 aliquots and then incubated at 4, 8, and 12 °C, respectively. For each temperature, analyses were repeated after 12, 24, and 48 h of storage. Despite the psychrotrophs growth increase, according to temperature rise, the lipolytic metabolism was not consistent and presented the lower index at 8 °C, suggesting an intensification of the proteolytic compensatory activity at this temperature. © 2013 Institute of Food Technologists®.

Enterotoxin genes in coagulase-negative and coagulase-positive staphylococci isolated from bovine milk

The objective of this study was to isolate and identify the main staphylococcal species causing bovine mastitis in 10 Brazilian dairy herds and study their capability to produce enterotoxins. Herds were selected based on size and use of milking technology, and farms were visited once during the study. All mammary glands of all lactating cows were screened using the California Mastitis Test (CMT) and a strip cup. A single aseptic milk sample (20. mL) was collected from all CMT-positive quarters. Identification of Staphylococcus spp. was performed using conventional microbiology, and PCR was used to determine the presence of enterotoxin-encoding genes (sea, seb, sec, and sed). Of the 1,318 CMT-positive milk samples, Staphylococcus spp. were isolated from 263 (19.9%). Of these isolates, 135 (51%) were coagulase-positive staphylococci (CPS) and 128 (49%) were coagulase-negative staphylococci (CNS). Eighteen different species of CNS were isolated, among which S. warneri, S. epidermidis and S. hyicus were the most frequent. The distribution of Staphylococcus species was different among herds: S. epidermidis was found in 8 herds, S. warneri was found in 7 herds, and S. hyicus in 6 herds. Some of the CNS species (S. saprophyticus ssp. saprophyticus, S. auricularis, S. capitis, and S. chromogenes) were isolated in only one of the farms. Genes related to production of enterotoxins were found in 66% (n = 85) of all CNS and in 35% of the CPS isolates. For both CNS and CPS isolates, the most frequently identified enterotoxin genes were sea, seb, and sec; the prevalence of sea differed between CPS (9.5%) and CNS (35.1%) isolates. Staphylococcus warneri isolates showed a greater percentage of sea than seb, sec, or sed, whereas S. hyicus isolates showed a greater percentage of sea than sec. Over 60% of CNS belonged to 3 major species, which carried 62.2 to 81.3% of the enterotoxin genes. The high prevalence highlights the potential for food poisoning caused by these species. For possible high-risk situations for food poisoning, such as milk produced with total bacterial counts greater than regulatory levels and stored under inappropriate temperatures, monitoring contamination with CNS could be important to protect human health. Because the prevalence of CNS intramammary infections in dairy herds is usually high, and these species can be found in great numbers in bulk milk, identification of risk factors for production of staphylococcal enterotoxins should be considered in future studies. © 2013 American Dairy Science Association.

Quantification of methomyl levels in cabbage, tomato, and soya milk using a renewable amperometric biosensor

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Influence of the combination of probiotic cultures during fermentation and storage of fermented milk

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Screening and determination of sulphonamide residues in bovine milk samples using a flow injection system

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Metal ions bound to the human milk immunoglobulin A: Metalloproteomic approach

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Transport of amino acids from milk whey by Caco-2 cell monolayer after hydrolytic action of gastrointestinal enzymes

The bioavailability of amino adds from milk whey protein hydrolysates was evaluated using diffusion of the substances through semi-permeable membranes (dialyzability) and transport by Caco-2 cell cultures. The hydrolysates with low degree of hydrolysis (LDH) and high degree of hydrolysis (HDH) were obtained after 120 min of reaction time at 50 degrees C after the initial addition of pepsin, followed by the addition of trypsin, chymotrypsin and carboxypeptidase-A. The proteins and hydrolysates were further subjected to in vitro digestion with pepsin plus pancreatin. HPLC was used to determine the concentrations of dialyzable amino adds (48.4% of the non-hydrolyzed proteins, 63.2% of the LDH sample and 58.3% of the HDH sample), demonstrating the greater dialyzability of the hydrolysates. The LDH and HDH whey protein hydrolysates prepared with pepsin, trypsin, chymotrypsin and carboxypeptidase-A showed only 14.7% and 20.8% of dialyzable small peptides and amino acids, respectively. The efficiency of absorption was demonstrated by the preferential transport of Ile, Lou and Arg through a layer of cells. In the LDH hydrolysate, Tyr was also transported. Prior high- and low-degree hydrolysis of the whey provided transport by 5.7% and 6.6%, respectively, in comparison with 23% for non-hydrolyzed proteins, considering the total amount of these amino adds that was applied to the cells. (C) 2014 Elsevier Ltd. All rights reserved.

Evaluation of the effect of supplementing fermented milk with quinoa flour on probiotic activity

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Occurrence of heat waves in Triangulo Mineiro and Alto Paranaiba and their effect on milk yield and feed intake in cattle

The aim of this study was to estimate milk production and food consumption during the occurrence of heat waves in the Triangulo Mineiro and Alto Paranaiba, MG by means of bioclimatic zoning based on the Temperature and Humidity Index (THI). Therefore a history of heat wave occurrence between the years 2000-2010 was compiled. The decline in milk production (DMP) and reduced food consumption (RFC) were simulated in cities where periods of heat waves were identified. Frutal and Ituiutaba had the highest rate of heat wave occurrence per year. The DMP and RFC showed bioclimatic differences between the cities of Uberaba, Ituiutaba and Frutal. The cities with the best bioclimatic conditions were Sacramento and Patrocinio, as they presented a THI classified outside of the emergency range, with a night THI of below 76 and without heat waves. Therefore, the occurrence of heat waves can impair food intake and decrease milk production, thereby most effectively demonstrating the effects of thermal stress on dairy cows in the Triangulo Mineiro and Alto Paranaiba, MG region.

Clonal profile, virulence and resistance of Staphylococcus aureus isolated from sheep milk

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)