Strategies to Improve the Quality of Goat Yogurt: Whey Protein Supplementation and Milk Pre-Treatment with High Shear Dispersion Assisted by Ultrasound.

This work investigated the fermentation kinetics and characteristics of goat yogurt supplemented with bovine whey protein isolate (WPI) (0%, 2.5% and 5.0%) subjected to high shear dispersion (HSD) assisted by ultrasound (US). Protein supplementation and the physical processes increased the electronegativity of the zeta potential (≤60%), whereas particle size reduction was observed only with physical processes (≤42%). The addition of 2.5% WPI reduced yogurt fermentation time by 30 min. After 24 h of storage at 7 °C, lactic acid bacteria counts did not differ between samples (≥8 log CFU/mL), and the supplementation was sufficient to increase the apparent viscosity (≤5.65 times) and water-holding capacity (WHC) of the yogurt (≤35% increase). However, supplementation combined with physical processes promoted greater improvements in these parameters (6.41 times in apparent viscosity and 48% in WHC) (p < 0.05), as confirmed by the denser and better-organized protein clusters observed in microscopic evaluation. Thus, both approaches proved to be promising alternatives to improve goat yogurt quality. Therefore, the decision to adopt these strategies, either independently or in combination, should consider cost implications, the product quality, and market demand.

Development and validation of a versatile analytical method for absolute quantification of seven oligosaccharides in human, bovine, and goat milk.

Oligosaccharides are significant in mammalian milk, where they serve as prebiotics that promote the growth of beneficial gut bacteria in infants. Comprehensive research of milk oligosaccharides requires precise and validated analytical methods for compositional studies. To address this need, the focus of our study was to develop and validate an analytical method using UPLC-MS/MS to quantify seven specific oligosaccharides found in mammalian milk. The developed and optimized method has adequate linearity, accuracy, and precision parameters. The detection (LOD) and quantification (LOQ) limits for the seven compounds ranged from 0.0018 to 0.0030 µg/mL and 0.0054-0.0063 µg/mL, respectively. The sample preparation method yielded recovery rates above 90.5 %. Furthermore, no significant matrix effect was observed. The validated method was successfully applied to human, goat, and bovine milk samples, demonstrating its proficiency in identifying variances in the concentration of oligosaccharides across different mammals. This versatile method will allow future research about factors affecting oligosaccharide composition.

Potentially pathogenic Staphylococcus aureus and Listeria spp. in Brazilian unpasteurized cheese production / Staphylococcus aureus e Listeria spp. potencialmente patogênicos na produção de queijos não pasteurizados

This study aimed to identify potentially pathogenic microorganisms (Listeria innocua, L. seeligeri, L. ivanovii, L. monocytogenes, Staphylococcus aureus, and several virulence genes) in unpasteurized cheese production in the northeastern region of the state of São Paulo, Brazil. Listeria species were detected in 68 (64.14%) out of 106 samples of bovine feces, swabs from milkers' and cheese handlers' hands, milking buckets, raw milk, whey, water, cheese processing surface,s and utensils. All the samples collected at one farm were contaminated with Listeria spp. L. innocua, L. seeligeri, L. ivanovii, or L. monocytogenes were not detected in the samples collected in this study. A set of 391 Staphylococcus spp. isolates were obtained in these samples, from which 60 (15.31%) were identified as S. aureus using PCR (Polymerase Chain Reaction). S. aureus carrying virulence genes (eta, hlg, seg, seh, sei) were detected in milk, in swabs from cheese handler's hands, whey, milk, sieves, buckets, and cheese. The hlg gene (encodes gamma hemolysin) was detected in all the S. aureus isolates. These findings show that poor hygienic practice is associated with a higher risk of pathogenic bacteria in milk or cheese, providing useful information for public health authorities to increase food safety surveillance and prevent the dissemination of pathogens.

O objetivo desse estudo foi identificar microrganismos potencialmente patogênicos (Listeria innocua, L. seeligeri, L. ivanovii, L. monocytogenes, Staphylococcus aureus e diversos genes de virulência) na produção de queijos de leite cru na região noroeste do Estado de São Paulo, Brasil. Listeria foram detectadas em 68 (64,14%) das 106 amostras obtidas de fezes bovinas, suabes das mãos de ordenhadores e queijeiros, baldes, leite cru, soro, água, superfícies e utensílios da produção de queijos. Todas as amostras coletadas em uma fazenda estavam contaminadas com Listeria spp. L. innocua, L. seeligeri, L. ivanovii, e L. monocytogenes não foram detectadas nas amostras coletadas nesse estudo. Um conjunto de 391 isolados de Staphylococcus spp. foram obtidos das amostras, e desses 60 (15,31%) foram identificados como S. aureus pela PCR (Polymerase Chain Reaction). S. aureus contendo genes de virulência (eta, hlg, seg, seh, sei) foram detectados em leite, mãos dos ordenhadores, soro, utensílios e queijos. O gene hlg (gama-hemolisina)foi detectado em todos os isolados de S. aureus.Esses resultados demonstram que práticas inadequadas de higiene estão associadas com um maior risco da presença de bactérias patogênicas no leite e queijos crus, fornecendo informações para as autoridades de saúde pública para incrementarem a vigilância e prevenirem a disseminação de patógenos.

Validation of a method employing liquid chromatography to identify and quantify glycomacropeptide of casein in raw milk / Validación de un método mediante cromatografía líquida para identificar y cuantificar glicomacropéptido de caseína en la leche cruda

Background: The information on official testing methods, or regulatory methods in Colombia to test whey in milk is limited; this restriction of information goes against the possibility of mitigating the risk of food fraud. Objectives: The validation of an HPLC method to determine casein glycomacropeptide (c-GMP), a protein that countries such as Brazil, Spain, and Ecuador have used as an indicator of raw milk adulteration with whey, was carried out. Methods: A 10mL sample of raw milk is precipitated with 24% TCA using ultrasound, a process followed by filtration. The collected fraction ensured the separation of c-GMP and then injected into the liquid chromatography. Results: A 30 minutes analysis allowed the determination of c-GMP with a retention time of 12.9 ± 0.5 minutes. The performance characteristics method in the validation exercise were: recovery percentage 99.97%, linearity R2> 0.95; % RSD accuracy <5.3%. Conclusion, the method exhibits desirable attributes for the intended purpose

Antecedentes: En Colombia la información de dominio público en metodologías de análisis de lactosuero en leche es limitada, restringiendo la posibilidad de acceder a ellas para mitigar el riesgo de fraude alimentario. Objetivos: Se realizó validación de un método por HPLC para determinar en leche cruda c-GMP, proteína usada como indicador de adulteración en países como Brasil y Ecuador. Metodos: Una muestra de 10mL de leche cruda es precipitada con TCA al 24% empleando ultrasonido, proceso seguido por filtración. La fracción recolectada aseguró la separación del c-GMP para luego inyectar al cromatógrafo líquido. Resultados: La determinación de c-GMP permitió el análisis en 30 minutos con tiempo de retención de 12,9 ± 0,5 minutos. Las características de desempeño del método en el ejercicio de validación fueron: porcentaje de recuperación 99,97%, linealidad R2>0,95; precisión %RSD< 5,3%. Conclusión: el método al final del ejercicio exhibe atributos para el fin previsto

Cariogenic Potential of Human and Bovine Milk on Enamel Demineralization.

The higher cariogenicity of human milk when compared with bovine milk is still a debatable subject. Therefore, we evaluated the effect of human or bovine milk exposure on biofilm composition and enamel demineralization using a validated cariogenic biofilm model. Streptococcus mutans UA159 biofilms (n = 8) were grown on human saliva-coated bovine enamel slabs of known surface hardness. The biofilms were exposed 8×/day to 0.9% NaCl (negative control), human milk, bovine milk, 7.0% lactose (active human milk control), 4.5% lactose (active bovine milk control), or 10% sucrose (positive control). The culture medium was changed twice daily, and the pH was analyzed as an indicator of biofilm acidogenicity. After 120 h of growth, biofilms were harvested to evaluate viable cells, and soluble and insoluble extracellular polysaccharides (EPS). Enamel demineralization was assessed by the percentage of surface hardness loss (%SHL). Data were analyzed by one-way ANOVA/Tukey's test (α = 5%). In terms of %SHL, negative control (7.7 ± 3.1), human milk control (13.3 ± 7.5), bovine milk control (15.3 ± 8.2), human milk (7.5 ± 5.0), and bovine milk (8.7 ± 6.3) did not differ among them (p > 0.05) but differed (p < 0.05) from sucrose (55.1 ± 5.4). The findings of enamel demineralization (%SHL) were statistically supported by the data of biofilm acidogenicity, bacterial counts and EPS biofilm composition. This experimental study suggests that human and bovine milk have low cariogenic potential to provoke caries lesions in enamel.

A New Acoustic-Based Approach for Assessing Induced Adulteration in Bovine Milk.

Milk is an important dietary requirement for many populations due to its high nutritional value. However, increased demand has also made it prone to fraudulent activity. In this sense, scientists have sought to develop simple, low-cost, and portable techniques to achieve quality control of milk in industry and farms as well. This work proposes a new instrumentation system based on acoustic propagation and advanced signal processing techniques to identify milk adulteration by industrial contaminants. A pair of transmitter-receiver low-cost piezoelectric transducers, configured in a pitch-catch mode, propagated acoustic waves in the bovine milk samples contaminated with 0.5% of sodium bicarbonate, urea, and hydrogen peroxide. Signal processing approaches such as chromatic technique and statistical indexes like the correlation coefficient, Euclidian norm and cross-correlation square difference were applied to identify the contaminants. According to the presented results, CCSD and RMSD metrics presented more effectiveness to perform the identification of milk contaminants. However, CCSD was 2.28 × 105 more sensitivity to distinguish adulteration in relation to RMSD. For chromatic clustering technique, the major selectivity was observed between the contamination performed by sodium bicarbonate and urea. Therefore, results indicate that the proposed approach can be an effective and quick alternative to assess the milk condition and classify its contaminants.

Risk factors associated with intramammary colonization with Mollicutes in dairy cattle from Southeast Brazil / Fatores de risco associados à colonização intramamária por Mollicutes em bovinos leiteiros do Sudeste brasileiro

Bacteria of Mollicutes Class are associated with intramammary infection and decrease in milk production. This study investigated the occurrence of Mollicutes and elucidated their risk factors in dairy herds from Southeast Brazil. For this, milk samples from 387 lactation cows from Minas Gerais, Rio de Janeiro and São Paulo States were subjected to the polymerase chain reaction (PCR) to detect Mollicutes. Species of Mycoplasma were investigated in Mollicutes positive samples by PCR, including Mycoplasma bovis, M. alkalescens, M. bovigenitalium, M. bovirhinis, M. arginini and A. laidlawii. An epidemiological questionnaire was applied to collect data on possible risk factors, which were assessed using Pearson's Chi-square test followed by odds ratio (P≤0.05). Mollicutes were reported in 21% (4/19) of the herds and 4% (16/387) of the animals, while 1% (5/387) were positive for M. bovis and 3% (11/387) for M. arginini. All samples were negative to the other agents. Herds with more than 150 animals [OR=3.51 (95% CI 1.11-11.08)], manual milking [OR=9.97 (95% CI 2.80-35.49)] and not-milking animals with mastitis last [OR=6.54 (95% CI 1.92-22.29)] were risk factors. The presence of these conditions may favor intramammary infection by Mollicutes in dairy herds from Southeast Brazil. This is the first report of M. bovis in Rio de Janeiro and M. arginini in the studied states.(AU)

Bactérias da Classe Mollicutes estão associadas à infecção intramamária e diminuição da produção leiteira. O objetivo deste estudo foi investigar a ocorrência de Mollicutes e elucidar seus fatores de risco em rebanhos leiteiros do sudeste brasileiro. Para isso, amostras de leite de 387 vacas em lactação dos estados de Minas Gerais, Rio de Janeiro e São Paulo foram submetidas à reação em cadeia da polimerase (PCR) para detectar Mollicutes. Espécies de Mycoplasma foram investigadas nas amostras positivas por PCR, incluindo Mycoplasma bovis, M. alkalescens, M. bovigenitalium, M. bovirhinis, M. arginini e A. laidlawii. Foi aplicado um questionário epidemiológico para a coleta de dados sobre possíveis fatores de risco, que foram avaliados pelo teste de Qui-Quadrado de Pearson seguido de odds ratio (P≤0.05). Mollicutes foram detectados em 21% (4/19) dos rebanhos e 4% (16/387) dos animais, enquanto 1% (5/387) destes foram positivos para m. bovis, 3% (11/387) para m. arginini, sendo todas as amostras negativas para os demais agentes. Rebanhos com mais de 150 animais [OR=3,51 (95% IC 1,11-11,08)], ordenha manual [OR=9,97 (95% IC 2,80-35,49)] e ausência de linha de ordenha [OR=6,54 (95% IC 1,92-22,29)] foram considerados fatores de risco. A presença dessas condições pode favorecer a infecção intramamária por Mollicutes em rebanhos leiteiros no sudeste do Brasil. Este é o primeiro relato de M. bovis no Rio de Janeiro e M. arginini nos estados estudados.(AU)

Risk factors associated with intramammary colonization with Mollicutes in dairy cattle from Southeast Brazil / Fatores de risco associados à colonização intramamária por Mollicutes em bovinos leiteiros do Sudeste brasileiro

Bacteria of Mollicutes Class are associated with intramammary infection and decrease in milk production. This study investigated the occurrence of Mollicutes and elucidated their risk factors in dairy herds from Southeast Brazil. For this, milk samples from 387 lactation cows from Minas Gerais, Rio de Janeiro and São Paulo States were subjected to the polymerase chain reaction (PCR) to detect Mollicutes. Species of Mycoplasma were investigated in Mollicutes positive samples by PCR, including Mycoplasma bovis, M. alkalescens, M. bovigenitalium, M. bovirhinis, M. arginini and A. laidlawii. An epidemiological questionnaire was applied to collect data on possible risk factors, which were assessed using Pearson's Chi-square test followed by odds ratio (P≤0.05). Mollicutes were reported in 21% (4/19) of the herds and 4% (16/387) of the animals, while 1% (5/387) were positive for M. bovis and 3% (11/387) for M. arginini. All samples were negative to the other agents. Herds with more than 150 animals [OR=3.51 (95% CI 1.11-11.08)], manual milking [OR=9.97 (95% CI 2.80-35.49)] and not-milking animals with mastitis last [OR=6.54 (95% CI 1.92-22.29)] were risk factors. The presence of these conditions may favor intramammary infection by Mollicutes in dairy herds from Southeast Brazil. This is the first report of M. bovis in Rio de Janeiro and M. arginini in the studied states.

Bactérias da Classe Mollicutes estão associadas à infecção intramamária e diminuição da produção leiteira. O objetivo deste estudo foi investigar a ocorrência de Mollicutes e elucidar seus fatores de risco em rebanhos leiteiros do sudeste brasileiro. Para isso, amostras de leite de 387 vacas em lactação dos estados de Minas Gerais, Rio de Janeiro e São Paulo foram submetidas à reação em cadeia da polimerase (PCR) para detectar Mollicutes. Espécies de Mycoplasma foram investigadas nas amostras positivas por PCR, incluindo Mycoplasma bovis, M. alkalescens, M. bovigenitalium, M. bovirhinis, M. arginini e A. laidlawii. Foi aplicado um questionário epidemiológico para a coleta de dados sobre possíveis fatores de risco, que foram avaliados pelo teste de Qui-Quadrado de Pearson seguido de odds ratio (P≤0.05). Mollicutes foram detectados em 21% (4/19) dos rebanhos e 4% (16/387) dos animais, enquanto 1% (5/387) destes foram positivos para m. bovis, 3% (11/387) para m. arginini, sendo todas as amostras negativas para os demais agentes. Rebanhos com mais de 150 animais [OR=3,51 (95% IC 1,11-11,08)], ordenha manual [OR=9,97 (95% IC 2,80-35,49)] e ausência de linha de ordenha [OR=6,54 (95% IC 1,92-22,29)] foram considerados fatores de risco. A presença dessas condições pode favorecer a infecção intramamária por Mollicutes em rebanhos leiteiros no sudeste do Brasil. Este é o primeiro relato de M. bovis no Rio de Janeiro e M. arginini nos estados estudados.

Risk factors associated with intramammary colonization with Mollicutes in dairy cattle from Southeast Brazil / Fatores de risco associados à colonização intramamária por Mollicutes em bovinos leiteiros do Sudeste brasileiro

ABSTRACT: Bacteria of Mollicutes Class are associated with intramammary infection and decrease in milk production. This study investigated the occurrence of Mollicutes and elucidated their risk factors in dairy herds from Southeast Brazil. For this, milk samples from 387 lactation cows from Minas Gerais, Rio de Janeiro and São Paulo States were subjected to the polymerase chain reaction (PCR) to detect Mollicutes. Species of Mycoplasma were investigated in Mollicutes positive samples by PCR, including Mycoplasma bovis, M. alkalescens, M. bovigenitalium, M. bovirhinis, M. arginini and A. laidlawii. An epidemiological questionnaire was applied to collect data on possible risk factors, which were assessed using Pearson's Chi-square test followed by odds ratio (P≤0.05). Mollicutes were reported in 21% (4/19) of the herds and 4% (16/387) of the animals, while 1% (5/387) were positive for M. bovis and 3% (11/387) for M. arginini. All samples were negative to the other agents. Herds with more than 150 animals [OR=3.51 (95% CI 1.11-11.08)], manual milking [OR=9.97 (95% CI 2.80-35.49)] and not-milking animals with mastitis last [OR=6.54 (95% CI 1.92-22.29)] were risk factors. The presence of these conditions may favor intramammary infection by Mollicutes in dairy herds from Southeast Brazil. This is the first report of M. bovis in Rio de Janeiro and M. arginini in the studied states.

RESUMO: Bactérias da Classe Mollicutes estão associadas à infecção intramamária e diminuição da produção leiteira. O objetivo deste estudo foi investigar a ocorrência de Mollicutes e elucidar seus fatores de risco em rebanhos leiteiros do sudeste brasileiro. Para isso, amostras de leite de 387 vacas em lactação dos estados de Minas Gerais, Rio de Janeiro e São Paulo foram submetidas à reação em cadeia da polimerase (PCR) para detectar Mollicutes. Espécies de Mycoplasma foram investigadas nas amostras positivas por PCR, incluindo Mycoplasma bovis, M. alkalescens, M. bovigenitalium, M. bovirhinis, M. arginini e A. laidlawii. Foi aplicado um questionário epidemiológico para a coleta de dados sobre possíveis fatores de risco, que foram avaliados pelo teste de Qui-Quadrado de Pearson seguido de odds ratio (P≤0.05). Mollicutes foram detectados em 21% (4/19) dos rebanhos e 4% (16/387) dos animais, enquanto 1% (5/387) destes foram positivos para m. bovis, 3% (11/387) para m. arginini, sendo todas as amostras negativas para os demais agentes. Rebanhos com mais de 150 animais [OR=3,51 (95% IC 1,11-11,08)], ordenha manual [OR=9,97 (95% IC 2,80-35,49)] e ausência de linha de ordenha [OR=6,54 (95% IC 1,92-22,29)] foram considerados fatores de risco. A presença dessas condições pode favorecer a infecção intramamária por Mollicutes em rebanhos leiteiros no sudeste do Brasil. Este é o primeiro relato de M. bovis no Rio de Janeiro e M. arginini nos estados estudados.

Sensory acceptance and physico-chemical composition of mixed minas frescal cheese / Aceitação sensorial e composição físico-química de queijo minas frescal misto

Buffalo milk presents higher proteins and lipids concentration than cow milk, which provides a better yield in cheese-making production and products with considerable sensory approval. However, buffalo milk is not regularly available throughout the year due to different handling conditions. Thus, to guarantee the supply of buffalo milk dairy products during the year, the addition of bovine milk is an alternative. Therefore, this study aimed to test the effect of a buffalo and bovine milk mixture for the Minas Frescal cheese elaboration by physico-chemical, sensory analysis and obtaining yield. The raw material was analysed for the parameters of acidity, density, fat, total solids and solid-not-fat. There were 3 Minas Frescal cheeses elaborated from 3 formulations: 100% buffalo milk, 100% bovine milk and the mixture of 50% of each milk. The cheeses were submitted to the Gravimetric and Gerber methods to obtain values of moisture and fat, as well as to obtain, indirectly, fat in dry matter. For bovine and buffalo milk, the parameters evaluated (acidity, density, fat, total solids and solids-not-fat) complied with Brazilian legislation and parameters described in the literature. For the bovine, mixed and buffalo fresh cheeses, values were obtained, respectively, for moisture (74.04, 60.93 and 63.61), fat in dry matter (44.35, 42.23 and 46.03) and cheese yield (27, 20.8 and 24.2), indicating a higher yield for the bovine Minas Frescal cheese and higher fat content for the buffalo cheese. The overall acceptance of the mixed Minas Frescal cheese was significantly superior to the bovine and buffalo cheese. The parameters of colour, appearance, texture, flavour and overall acceptance were above 8 points in the hedonic scale ('moderately liked' to 'extremely liked'), and the aroma attribute scored was above 7 ('I enjoyed regularly' to 'moderately liked'). Therefore, the elaboration of Minas Frescal cheese from the mixture of 2 matrices (buffalo and bovine milk) demonstrated technological viability with the potential to meet the demands of the consumer market.

O leite de búfala possui maior porcentagem de todos os componentes tornando-o uma matéria-prima adequada com potencial para fornecer um maior rendimento e qualidade nutricional na produção de queijo. No entanto, o leite de búfalo não está disponível regularmente ao longo do ano devido a diferentes condições de manejo. Assim, para garantir a oferta de produtos lácteos com leite de búfala independentemente da época, a adição de leite bovino pode ser vista como uma alternativa. Logo, este trabalho teve como objetivo testar o efeito da mistura do leite de búfalo e bovino na elaboração do queijo Minas Frescal por meio de análises físico-químicas e sensoriais e obtenção do rendimento economico. A matéria-prima foi analisada quanto aos parâmetros: acidez titulável, densidade, gordura, sólidos totais e sólidos totais desengordurados. Três variedades de queijo Minas Frescal foram elaboradas a partir de três formulações: 100% de leite de búfala, 100% de leite bovino e da mistura de 50% de cada leite. Os queijos foram submetidos aos métodos Gavimetric e Gerber para obtenção de umidade e gordura, bem como, indiretamente, para obtenção de matéria gorda no extrato seco. Para o leite bovino e de búfala, os parâmetros avaliados (acidez titulável, densidade, gordura, sólidos totais e sólidos totais desengordurados) estavam de acordo com a legislação brasileira e parâmetros descritos na literatura. Para os queijos bovino, misto e de búfala, foram obtidos, respectivamente, para: umidade (74,04; 60,93 e 63,61), gordura na matéria seca (44,35; 42,23 e 46,03) e rendimento econômico (27, 20,8 e 24,2) indicando maior rendimento o queijo Minas Frescal bovino e maior teor de gordura para o queijo búfalo. A aceitação global do queijo Minas Frescal misto foi significativamente superior ao do queijo bovino e bubalino. Os parâmetros de cor, aparência, textura, sabor e aceitabilidade global foram acima de 8 pontos (entre "gostei moderadamente" e "extremamente gostei") e o atributo aroma obteve pontuação acima de 7 ("gostei regularmente" para "gostei moderadamente"). Portanto, a elaboração do queijo Minas Frescal da mistura de leite bovino ao búfalo demonstrou potencial para atender as demandas do mercado consumidor.

Influencia de las estaciones del año en la composición y la calidad sanitaria de leche bovina del Valle de Lerma, Salta / Seasonal influence on chemical composition and sanitary quality of bovine milk of the Lerma´s Valley, Argentina

Resumen Con el objetivo de conocer la influencia de las estaciones del año respecto de la composición y la calidad sanitaria de leche bovina de la cuenca del Valle de Lerma se llevó adelante el análisis de las muestras de leche remitidas por la industria al Laboratorio de Leche de la Universidad Nacional de Salta durante la primavera (Pr, n:104), el verano (Ve, n:131) y el invierno (In, n: 118) de los años 2017 y 2019. Se determinó el porcentaje de grasa (% G) y de proteína (% P), el punto de descenso crioscópico (DC) y el recuento de células somáticas/ml (RCS/ml). El análisis estadístico se realizó utilizando el programa InfoStat 2019p. El modelo respondió a un DCA. El % G y P fueron analizados mediante ANOVA. Mientras que para DC y RCS se utilizó ANOVA no paramétrico de Kruskal Wallis. La comparación entre medias fue a través del Test de Tukey (p<0,05). El % G resultó de acuerdo a los estándares establecidos por la legislación argentina en todas las estaciones del año, aunque el valor en el In fue inferior al de Ve (3,49 vs 3,64, p=0,0009). El % P resultó similar en las 3 estaciones, pero por debajo de los estándares nacionales (In: 3,24, Pr 3,26, Ve: 3,26). El DC (°C) si bien fue inferior al máximo adecuado difirió entre el In (-0,522) y la Pr (-0,519) y el Ve (-0,518) (p=0,0023). El RCS en el In y la Pr fue similar (264000 vs. 228000 cel/ml, respectivamente); mientras que en el Ve resultó superior (p=0,0012) mostrando valores promedio mayores (430000 cel/ml) al límite establecido por los estándares nacionales. Al comparar los resultados obtenidos con los estándares de composición química y sanitaria de referencia en Argentina se observa que, salvo los niveles de proteína y el RCS durante el verano, el resto de los parámetros se encuentran conforme a lo establecido en la legislación nacional.

Abstract The aim of this study was to determine the seasonal influence in bovine milk composition and sanitary quality for Lerma Valley basin. Samples sent by dairy industries to National University of Salta Milk Laboratory during spring (Pr, n: 104), summer (Ve, n: 131) and winter (In, n: 118) of the years 2017 and 2019 were analyzed. Fat (% F) and protein (% P) percentages, freezing point (FP) and somatic cell count / ml (RCS / ml) were determined. Statistical analysis was performed using the InfoStat 2019p program. The model responded to a CRD. % F and % P were analyzed by ANOVA, while for FP and SCC non-parametric ANOVA from Kruskal Wallis was used. Tukey Test (p <0.05) was used for means comparasions. % F was according to Argentine legislation in all seasons of the year, although ln value was lower than that Su (3.49 vs. 3.64, p= 0.0009). % P was similar in the 3 stations, but below the national standards (Wi: 3.24, Sp: 3.26, Su: 3.26). FP (° C), differed between Wi (-0.522) and Sp (-0.519) and Su (-0.518) (p=0,0023), although values were below the upper range value. SCC (cel / ml) Wi In and Sp was similar (264000 vs. 228000 cel/ml, respectively), while in Su it was higher (p = 0.0012) showing higher average values (430,000 cel / ml) than the limit established by national standards. The results obtained in this study were accord with the chemical and sanitary composition of reference in Argentina, except for protein levels and SCC during the summer.

Isolation and identification of Yersinia enterocolitica in bovine milk samples of bulk tanks from dairy farms in São Paulo, Brazil / Isolamento e identificação de Yersinia enterocolitica em amostras de leite cru bovino a partir de tanques de expansão, São Paulo, Brasil

Milk and its derivatives are good substrates for the proliferation of pathogenic and quality-deteriorating microorganisms, demanding rigorous care with milking, processing, and storage. Among the various bacteria that can grow in raw refrigerated milk, Yersinia enterocolitica, is an invasive enteropathogen of humans. This bacterium can cause a number of intestinal and extraintestinal clinical symptoms, ranging from mild gastroenteritis to mesenteric lymphadenitis, similar to appendicitis. To evaluate the prevalence of pathogenic Yersinia enterocolitica in raw milk from bulk milk tanks located in the State of São Paulo, 102 bovine milk samples (one per dairy farm) were evaluated by microbiological analyses, followed by biochemical tests PCR and genetic sequencing. Microbiological testing did not isolate Y. enterocolitica. However, PCR analysis revealed six samples that were positive for Y. enterocolitica (5.9%), confirmed by genetic sequencing. Only the inv gene was detected, which is present in virulent and avirulent Y. enterocolitica strains. There was great difficulty in microbiological isolation due to the difficulty of competitiveness of Y. enterocolitica in a very rich microbiota of raw milk. Although virulence genes known to be present in potentially pathogenic strains of Y. enterocolitica have not been identified, the presence of this pathogen in milk from expansion tanks...(AU)

O leite e seus derivados possuem substratos que favorecem o desenvolvimento de micro-organismos patogênicos e deteriorantes, devido a isso, cuidados rigorosos são exigindo durante a ordenha, processamento e seu armazenamento. Dentre os vários grupos de bactérias que podem contaminar o leite refrigerado cru está Yersinia enterocolitica. Esta bactéria pode causar a uma série de sintomas clínicos intestinais e extraintestinais, variando de gastroenterite leve a linfadenite mesentérica, semelhante à apendicite. Para avaliar a prevalência de Y. enterocolitica patogênica no leite cru de tanques de expansão localizados no estado de São Paulo, foram avaliadas 102 amostras de leite bovino, por análises microbiológicas, seguido de provas bioquímicas; a Reação em Cadeia de Polimerase (PCR) e sequenciamento genético. Não houve o isolamento de Y. enterocolitica pelas provas microbiológicas clássicas. No entanto, a análise de PCR, realizada diretamente do leite, revelou seis (6) amostras positivas para Y. enterocolitica (5,9%), confirmadas por sequenciamento genético. Somente o gene inv, foi detectado, que pode estar presente em cepas virulentas e avirulentas. Houve dificuldade de isolamento microbiológico devido à dificuldade de competitividade da Y. enterocolitica em uma microbiota muito rica do leite cru. Ainda que não tenham sido identificados os genes de virulência que sabidamente estão...(AU)

Isolation and identification of Yersinia enterocolitica in bovine milk samples of bulk tanks from dairy farms in São Paulo, Brazil / Isolamento e identificação de Yersinia enterocolitica em amostras de leite cru bovino a partir de tanques de expansão, São Paulo, Brasil

Milk and its derivatives are good substrates for the proliferation of pathogenic and quality-deteriorating microorganisms, demanding rigorous care with milking, processing, and storage. Among the various bacteria that can grow in raw refrigerated milk, Yersinia enterocolitica, is an invasive enteropathogen of humans. This bacterium can cause a number of intestinal and extraintestinal clinical symptoms, ranging from mild gastroenteritis to mesenteric lymphadenitis, similar to appendicitis. To evaluate the prevalence of pathogenic Yersinia enterocolitica in raw milk from bulk milk tanks located in the State of São Paulo, 102 bovine milk samples (one per dairy farm) were evaluated by microbiological analyses, followed by biochemical tests PCR and genetic sequencing. Microbiological testing did not isolate Y. enterocolitica. However, PCR analysis revealed six samples that were positive for Y. enterocolitica (5.9%), confirmed by genetic sequencing. Only the inv gene was detected, which is present in virulent and avirulent Y. enterocolitica strains. There was great difficulty in microbiological isolation due to the difficulty of competitiveness of Y. enterocolitica in a very rich microbiota of raw milk. Although virulence genes known to be present in potentially pathogenic strains of Y. enterocolitica have not been identified, the presence of this pathogen in milk from expansion tanks...

O leite e seus derivados possuem substratos que favorecem o desenvolvimento de micro-organismos patogênicos e deteriorantes, devido a isso, cuidados rigorosos são exigindo durante a ordenha, processamento e seu armazenamento. Dentre os vários grupos de bactérias que podem contaminar o leite refrigerado cru está Yersinia enterocolitica. Esta bactéria pode causar a uma série de sintomas clínicos intestinais e extraintestinais, variando de gastroenterite leve a linfadenite mesentérica, semelhante à apendicite. Para avaliar a prevalência de Y. enterocolitica patogênica no leite cru de tanques de expansão localizados no estado de São Paulo, foram avaliadas 102 amostras de leite bovino, por análises microbiológicas, seguido de provas bioquímicas; a Reação em Cadeia de Polimerase (PCR) e sequenciamento genético. Não houve o isolamento de Y. enterocolitica pelas provas microbiológicas clássicas. No entanto, a análise de PCR, realizada diretamente do leite, revelou seis (6) amostras positivas para Y. enterocolitica (5,9%), confirmadas por sequenciamento genético. Somente o gene inv, foi detectado, que pode estar presente em cepas virulentas e avirulentas. Houve dificuldade de isolamento microbiológico devido à dificuldade de competitividade da Y. enterocolitica em uma microbiota muito rica do leite cru. Ainda que não tenham sido identificados os genes de virulência que sabidamente estão...

Relationship between climatic variables and the variation in bulk tank milk composition using canonical correlation analysis.

A number of studies have addressed the relations between climatic variables and milk composition, but these works used univariate statistical approaches. In our study, we used a multivariate approach (canonical correlation) to study the impact of climatic variables on milk composition, price, and monthly milk production at a dairy farm using bulk tank milk data. Data on milk composition, price, and monthly milk production were obtained from a dairy company that purchased the milk from the farm, while climatic variable data were obtained from the National Institute of Meteorology (INMET). The data are from January 2014 to December 2016. Univariate correlation analysis and canonical correlation analysis were performed. Few correlations between the climatic variables and milk composition were found using a univariate approach. However, using canonical correlation analysis, we found a strong and significant correlation (rc = 0.95, p value = 0.0029). Lactose, ambient temperature measures (mean, minimum, and maximum), and temperature-humidity index (THI) were found to be the most important variables for the canonical correlation. Our study indicated that 10.2% of the variation in milk composition, pricing, and monthly milk production can be explained by climatic variables. Ambient temperature variables, together with THI, seem to have the most influence on variation in milk composition.

Atividade antisséptica do óleo essencial de Lippia origanoides Cham. (Alecrim-pimenta) na presença de leite bovino / Antiseptic activity of the essential oil of Lippia origanoides in the presence of bovine milk

Objetivou-se determinar atividade antisséptica do óleo essencial de Lippia origanoides na presença de leite bovino. A composição química do óleo essencial de alecrim pimenta foi determinada por cromatografia gasosa acoplada à espectrometria de massas (CG-EM), sendo detectados 53 compostos, dos quais 16 foram identificados (>0,1% área total). O carvacrol (32,7%), p-cimeno (23%), timilmetil éter, cariofileno (7,98%) e o γ-terpineno (5,40%) foram os componentes mais abundantes. A concentração inibitória mínima para Staphylococcus aureus ATCC 25923 e E. coli ATCC 8739 foi de 60µL/mL, enquanto para Salmonella Choleraesuis ATCC 35640 foi de 90µL/mL. A concentração bactericida mínima foi de 120µL/mL para as três bactérias. Avaliou-se a atividade antisséptica do óleo essencial na concentração de 120µL/mL na presença de leite bovino sobre as mesmas cepas bacterianas. O óleo em estudo apresentou efeito inibitório do crescimento das cepas em diferentes tempos de ação (p<0,05). S. aureus apresentou maiores índices de inibição após 5 min de contato e Escherichia coli e Salmonella Choleraesuis após 15 min. O óleo essencial de alecrim-pimenta revelou ser um potencial antimicrobiano natural, mesmo na presença de matéria orgânica constituída de uma matriz nutricional complexa que é o leite bovino.(AU)

This study aimed to determine the antiseptic activity of the essential oil of Lippia origanoides in the presence of bovine milk. The essential oil chemical composition was determined by gas chromatography-mass spectrometry (CG EM) 53 compounds were detected, of which 16 were identified (>0.1% total area). The carvacrol (32.7%), p-cymene (23%), thymil methyl ether (10.03%), caryophyllene (7.98 %) and γ-terpinene (5.40%) were the most abundant components. The minimum inhibitory concentration for Staphylococcus aureus ATCC 25923 and Escherichia coli ATCC 8739 was 60uL/mL, as for this Salmonella Choleraesuis ATCC 35640 was 90uL/mL. The minimum bactericidal concentration was 120µL/mL for all three bacteria. We evaluated the antiseptic activity of the essential oil in the concentration of 120µL/mL in the presence of bovine milk for the same bacterial strains. The oil under study It showed an inhibitory effect of growth of the strains in different action times (p <0.05). S. aureus showed higher inhibition rates after 5 min of contact and E. coli and Salmonella Choleraesuis after 15 min. The essential oil Lippia origanoides proved to be a natural antimicrobial potential even in the presence of organic matter consists of a complex nutritional matrix is bovine milk.(AU)

Electrical field assisted matrix solid phase dispersion as a powerful tool to improve the extraction efficiency and clean-up of fluoroquinolones in bovine milk.

This work presents a new method by electrical matrix solid phase dispersion for the extraction and clean-up of marbofloxacin, ofloxacin, norfloxacin, ciprofloxacin, enrofloxacin, difloxacin and sarafloxacin in bovine milk. Composition and pH of the eluent, applied electrical potential and polarity were optimized by experimental designs. The combination of the chromatographic and electrophoretic mechanisms allowed the extraction and clean-up in one step with low organic solvent consumption, high extraction throughput and elution automation. Linearity, precision, trueness and limit of quantification were evaluated and provided values in accordance with other methods recently developed for the analysis of fluoroquinolones in milk. This technique proved to be promising for the extraction and clean-up of ionizable analytes in different milk matrices.

Do different standard plate counting (IDF/ISSO or AOAC) methods interfere in the conversion of individual bacteria counts to colony forming units in raw milk?

AIMS: This study aimed to establish the correlation between individual bacterial count (IBC) obtained by flow cytometry and the number of colony forming units (CFU) determined by standard plate count (SPC) in raw milk using two different reference methodologies: the methodology of the International Dairy Federation (IDF) - International Organization for Standardization (ISO) 4833, incubation for 72 h at 30°C and the methodology of the Association of Official Analytical Chemists (AOAC), incubation for 48 h at 35°C. METHODS AND RESULTS: For this, 100 bovine milk samples (80 ml) from different farms were collected in a sterile bottle and maintained refrigerated at 4°C and were delivered to the laboratory. In the laboratory, the samples were divided into two vials of 40 ml each. Then, half of the vials were forwarded for the SPC analysis, and the other half were analysed using the equipment BactoScan FC. The analyses by flow cytometry and SPC were performed at the same time (maximum deviation of +/- 1 h). To transform the data from IBC ml(-1) to CFU ml(-1) (IDF or AOAC methodology), a standard linear regression equation was used, as recommended by IDF/ISO-196. The difference between the reference methodologies affects the equation that transforms IBC into CFU and therefore the accuracy of the results. The results estimated by the equation using the ISO 4833 methodology were on average 0·18 log units higher than the results estimated using the equation using the AOAC methodology. CONCLUSIONS: After the comparison of the methodologies, it was concluded that there is an impact of the reference methodologies on the conversion of the results from IBC to CFU. SIGNIFICANCE AND IMPACT OF THE STUDY: Depending on the methodology adopted by each laboratory or country, there may not be equivalence in the results. Hence, the laboratories specialized in milk quality analysis that have changed their methodology for analysis, passing from the MAPA (AOAC) methodology to the IDF standard, need to develop new conversion equations to make their results in CFU ml(-1) consistent regardless of the reference methodology.

Atividade antisséptica do óleo essencial de Lippia origanoides Cham. (Alecrim-pimenta) na presença de leite bovino / Antiseptic activity of the essential oil of Lippia origanoides in the presence of bovine milk

This study aimed to determine the antiseptic activity of the essential oil of Lippia origanoides in the presence of bovine milk. The essential oil chemical composition was determined by gas chromatography-mass spectrometry (CG EM) 53 compounds were detected, of which 16 were identified (>0.1% total area). The carvacrol (32.7%), p-cymene (23%), thymil methyl ether (10.03%), caryophyllene (7.98 %) and γ-terpinene (5.40%) were the most abundant components. The minimum inhibitory concentration for Staphylococcus aureus ATCC 25923 and Escherichia coli ATCC 8739 was 60uL/mL, as for this Salmonella Choleraesuis ATCC 35640 was 90uL/mL. The minimum bactericidal concentration was 120μL/mL for all three bacteria. We evaluated the antiseptic activity of the essential oil in the concentration of 120μL/mL in the presence of bovine milk for the same bacterial strains. The oil under study It showed an inhibitory effect of growth of the strains in different action times (p <0.05). S. aureus showed higher inhibition rates after 5 min of contact and E. coli and Salmonella Choleraesuis after 15 min. The essential oil Lippia origanoides proved to be a natural antimicrobial potential even in the presence of organic matter consists of a complex nutritional matrix is bovine milk.(AU)

Objetivou-se determinar atividade antisséptica do óleo essencial de Lippia origanoides na presença de leite bovino. A composição química do óleo essencial de alecrim pimenta foi determinada por cromatografia gasosa acoplada à espectrometria de massas (CG-EM), sendo detectados 53 compostos, dos quais 16 foram identificados (>0,1% área total). O carvacrol (32,7%), p-cimeno (23%), timilmetil éter, cariofileno (7,98%) e o γ-terpineno (5,40%) foram os componentes mais abundantes. A concentração inibitória mínima para Staphylococcus aureus ATCC 25923 e E. coli ATCC 8739 foi de 60μL/mL, enquanto para Salmonella Choleraesuis ATCC 35640 foi de 90μL/mL. A concentração bactericida mínima foi de 120μL/mL para as três bactérias. Avaliou-se a atividade antisséptica do óleo essencial na concentração de 120μL/mL na presença de leite bovino sobre as mesmas cepas bacterianas. O óleo em estudo apresentou efeito inibitório do crescimento das cepas em diferentes tempos de ação (p<0,05). S. aureus apresentou maiores índices de inibição após 5 min de contato e Escherichia coli e Salmonella Choleraesuis após 15 min. O óleo essencial de alecrim-pimenta revelou ser um potencial antimicrobiano natural, mesmo na presença de matéria orgânica constituída de uma matriz nutricional complexa que é o leite bovino.(AU)

High-throughput method for the determination of residues of ß-lactam antibiotics in bovine milk by LC-MS/MS.

This study describes the development and validation procedures for scope extension of a method for the determination of ß-lactam antibiotic residues (ampicillin, amoxicillin, penicillin G, penicillin V, oxacillin, cloxacillin, dicloxacillin, nafcillin, ceftiofur, cefquinome, cefoperazone, cephapirine, cefalexin and cephalonium) in bovine milk. Sample preparation was performed by liquid-liquid extraction (LLE) followed by two clean-up steps, including low temperature purification (LTP) and a solid phase dispersion clean-up. Extracts were analysed using a liquid chromatography-electrospray-tandem mass spectrometry system (LC-ESI-MS/MS). Chromatographic separation was performed in a C18 column, using methanol and water (both with 0.1% of formic acid) as mobile phase. Method validation was performed according to the criteria of Commission Decision 2002/657/EC. Main validation parameters such as linearity, limit of detection, decision limit (CCα), detection capability (CCß), accuracy, and repeatability were determined and were shown to be adequate. The method was applied to real samples (more than 250) and two milk samples had levels above maximum residues limits (MRLs) for cloxacillin - CLX and cefapirin - CFAP.

Recovery of casein-derived peptides with in vitro inhibitory activity of angiotensin converting enzyme (ACE) using aqueous two-phase systems.

Peptides inhibiting the activity of angiotensin converting enzyme (ACE) were obtained by trypsin-catalyzed hydrolysis of bovine milk casein, performed at 37°C, during 1, 2, 5, 8 and 24h. Results of in vitro inhibitory activity ranged between 13.4% and 78.5%. The highest ACE inhibitory activity was evidenced for hydrolysates obtained after 2h of reaction. Aqueous two-phase systems (ATPS) formed by polyethylene glycol of 1500gmol-1 (PEG 1500)+sodium phosphate or potassium phosphates were produced and evaluated, in terms of partition coefficients (K) and extraction yields (y), to recovery the casein hydrolysates at room temperature. In ATPS containing sodium phosphate, the peptides showed a slightly greater affinity toward the bottom salt-rich phase (0.1≤K≤0.9; 5.7%≤y≤47%). In the case of ATPS containing potassium phosphates, these molecules showed substantially greater affinity toward the top polymer-rich phase (137≤K≤266; y≥99%). These results point out extraction using PEG 1500/potassium phosphate ATPS is an efficient technique to recover casein hydrolysates containing ACE inhibitors peptides. Outlined data will be helpful in integrating such unit operation to larger scale processes.