Greek vs traditional yogurts: Sensory and physicochemical comparison

ABSTRACT Greek yogurt (GY) has gained popularity in recent years for its marked texture, taste, and nutritional characteristics compared to traditional yogurt (TY). The objective of this work was to analyze the physicochemical, sensory, and lipid profile of GY and TY with blueberry flavor, both manufactured by a local industry in the state of Rio Grande do Sul, Brazil. Protein and lipid content, as well as humidity, ash, and fatty acid profile were quantified and a sensory evaluation was completed using the affective method. The physicochemical results showed 1.5% and 2.3% more proteins and lipids, respectively, for GY compared to TY. The humidity in TY was 10% lower than in GY. Eighteen types of polyunsaturated, saturated, monounsaturated fatty acids were identified, with a high proportion of C14, C16, and C18. Sensory analysis showed a preference for GY over TY (64% versus 36%, p0.05). Both the protein and lipid content, associated with creaminess, likely influence better acceptance of GY.

RESUMEN El yogur griego (YG) ha ganado popularidad durante los últimos años por su marcada textura, sabor y características nutricionales en comparación con el yogur tradicional (YT). El objetivo de este trabajo fue analizar el perfil fisicoquímico, sensorial y lipídico de YG y YT con sabor a arándano, ambos fabricados por una industria ubicada en el estado de Rio Grande do Sul, Brasil. Fueron cuantificados el contenido de proteínas, lípidos, humedad y cenizas, así como también el perfil de ácidos grasos y la evaluación sensorial por método afectivo. Los resultados fisicoquímicos mostraron que YG contiene 1,5% y 2,3% más de proteínas y lípidos, respectivamente, en comparación con YT (p0,05) en relación a la aceptación de los atributos color, olor, sabor y acidez. Los atributos cuerpo, apariencia y textura presentaron mejores scores de aceptación para el YG. Tanto el contenido de proteínas y lípidos, asociados a la cremosidad, probablemente hayan influenciado una mejor aceptación del YG.

Antimicrobial effect of ethanol extract of leaf neem (Azadirachta indica A. Juss) on Listeria monocytogenes

Listeria monocytogenes es un patógeno causante de enfermedades alimentarias. En la búsqueda de controlar su propagación utilizando sustancias naturales se planteó el objetivo de mostrar si el extracto etanólico foliar de neem (Azadirachta Indica A. Juss.) tiene efecto antimicrobiano sobre L. monocytogenes ICTA-12446. El extracto se obtuvo a partir de hojas de neem sometidas a secado por 8 días, se redujeron de tamaño mecánicamente, se sometieron a maceración en frío por 3 días usando etanol 96% en recipientes ámbar, se filtró y concentró en rota evaporador. Se estandarizó el concentrado con dimetilsulfóxido (DMSO) a una concentración de 60 mg/L. Listeria monocytogenes ICTA-12446, fue inoculado en caldo nutriente junto con soluciones del extracto a diferentes concentraciones (20, 30, 40, 50 y 60 mg/L), se emplearon tiempos de contacto (2.5, 5, 10 y 15 minutos). Cumplido cada tiempo se realizaron diluciones seriadas e inocularon en agar nutritivo por extensión durante 24 h a 37ºC. Se efectuó el recuento en Unidades Formadoras de Colonias UFC. Al comparar las concentraciones del extracto se evidencia entre 20 y 60 mg/mL diferencia significativa, mientras que en 30, 40 y 50 mg/mL un comportamiento similar. Al contrastar tiempos de contacto, se observa que entre el tiempo 2.5 min y los restantes un p=0,03. El tiempo mínimo donde existió inhibición fue 2.5 minutos, y concentración mínima inhibitoria de 20 mg/mL. Los cuatro tiempos de contacto arrojan porcentajes de inhibición microbiana de 100% al emplear 60mg/mL. Se concluye que el extracto etanólico foliar de neem posee un efecto inhibitorio sobre Listeria monocytogenes(AU)

Listeria monocytogenes is a pathogen causing foodborne illness. In seeking to control its spread using natural substances in order to show if the leaf ethanol extract of neem (Azadirachta indica A. Juss) has antimicrobial effect on L. monocytogenes ICTA-12446, was proposed. The extract was obtained from neem leaves, which was subjected to drying for 8 days. It was reduced in size mechanically, and subjected to cold soak for 3 days, using 96% ethanol in amber vessels, filtered and concentrated in rot evaporator. Concentrated was solubilized with dimethylsulfoxide (DMSO) and standarized to achieve a concentration of 60 mg/mL Listeria monocytogenes was inoculated in nutrient broth with extract solutions at different concentrations (20, 30, 40, 50 and 60mg/mL), four contact times (2.5, 5, 10 and 15 minutes) were used. Completed each time it was diluted and inoculated on nutrient agar by extension for 24h at 37ºC. The count of Colony Forming Units UFC was taking. Comparing the concentrations of the extract between 20 and 60mg /mL significant difference was appreciate, while 30, 40 and 50 mg/mL show a similar behavior. Contrasting contact times observed between time 2.5 min and the remaining p = 0.03. The minimum time where there was some kind of inhibition was 2.5 minutes, and minima inhibitory concentration of 20mg/mL. The four contact times yield microbial inhibition percentages of 100% by using 60mg/L. It is concluded that ethanol extract of neem leaf has an inhibitory effect on L. monocytogenes(AU)

Efecto bacteriostático y/o bactericida del xilitol sobre cultivos de Listeria monocytogenes / Bacteriostatic effect and/or xylitol bactericide of crops on Listeria Monocytogenes

Listeria monocytogenes ha sido considerado como un patógeno emergente causante de enfermedades alimentarias. En la búsqueda de una vía alterna biocontroladora de su propagación, se propone al xilitol como posible agente bacteriostático y/o bactericida. El xilitol es un poliol derivado de la hidrogenación del monosacárido xilosa de relevancia en la industria farmacéutica por su efecto anticariogénico. Para comprobar el efecto del xilitol como posible agente bacteriostático y/o bactericida sobre Listeria monocytogenes, se determinó la concentración mínima inhibitoria (CMI), el tiempo mínimo de inhibición (TMI) y la concentración bactericida mínima (CBM) de soluciones de xilitol en cultivos de Listeria monocytogenes ATCC 7635. Se aplicó el método de difusión en agar, utilizando soluciones de xilitol en concentraciones de 0 a 10%, respectivamente, para la CMI. El TMI se determinó por curvas de crecimiento en caldo Soya tripticasa con soluciones de 1, 2, 3, 5, 8, 9, 10 y 20% de xilitol, respectivamente, con un inoculo inicial de 108 UFC de Listeria monocytogenes por mL en cada solución. Se observó que la CMI fue con la solución del 1% de xilitol; el TMI fue de 10 horas con las concentraciones de 1 a 10% y de 7 horas al aplicar 20% xilitol. Se comprobó que efectivamente el xilitol tiene poder bacteriostático sobre Listeria monocytogenes (p<0.001), más sin embargo, no se obtuvo efecto bactericida en los ensayos realizados.

Listeria monocytogenes has been considered as an emerging pathogen causing foodborne illness. In the search for an alternate route biocontrol propagation, xylitol has been proposed as a possible bacteriostatic and / or bactericide. Xylitol is a polyol derived from the hydrogenation of xylose monosaccharide of importance in the pharmaceutical industry for its anti-cariogenic effect. To check the possible effect of xylitol as bacteriostatic and /or bactericidal against Listeria monocytogenes, it was determined the minimum inhibitory concentration (MIC), the time minimum inhibition (TMI) and minimum bactericidal concentration (MBC) of xylitol solutions on Listeria monocytogenes ATCC 7635. The agar diffusion method was applied, using xylitol solutions at concentrations of 0-10%, respectively, for the MIC. The TMI was determined by growth curves in trypticase soy broth with solutions 1, 2, 3, 5, 8, 9, 10 and 20% of xylitol, respectively, with an initial inoculum of 108 CFU per ml of Listeria monocytogenes in each solution. MIC observed was the solution 1% of xylitol; the TMI was 10 hours to concentrations of 1 to 10% and 7 hours to apply 20% xylitol. It was found that xylitol has bacteriostatic power on Listeria monocytogenes (p <0.001), but not bactericide effect.

[Bacteriostatic effect and/or xylitol bactericide of crops on Listeria Monocytogenes]. / Efecto bacteriostático y/o bactericida del xilitol sobre cultivos de Listeria monocytogenes.

Listeria monocytogenes has been considered as an emerging pathogen causing foodborne illness. In the search for an alternate route biocontrol propagation, xylitol has been proposed as a possible bacteriostatic and / or bactericide. Xylitol is a polyol derived from the hydrogenation of xylose monosaccharide of importance in the pharmaceutical industry for its anti-cariogenic effect. To check the possible effect of xylitol as bacteriostatic and/or bactericidal against Listeria monocytogenes, it was determined the minimum inhibitory concentration (MIC), the time minimum inhibition (TMI) and minimum bactericidal concentration (MBC) of xylitol solutions on Listeria monocytogenes ATCC 7635. The agar diffusion method was applied, using xylitol solutions at concentrations of 0-10%, respectively, for the MIC. The TMI was determined by growth curves in trypticase soy broth with solutions 1, 2, 3, 5, 8, 9, 10 and 20% of xylitol, respectively, with an initial inoculum of 108 CFU per ml of Listeria monocytogenes in each solution. MIC observed was the solution 1% of xylitol; the TMI was 10 hours to concentrations of 1 to 10% and 7 hours to apply 20% xylitol. It was found that xylitol has bacteriostatic power on Listeria monocytogenes (p < 0.001), but not bactericide effect.

Efecto bacteriostático y/o bactericida del extracto de gel de Aloe vera sobre cultivos de Listeria monocytogenes

Listeria monocytogenes es una bacteria responsable de enfermedades transmitidas por alimentos (ETA). Para comprobar el efecto del extracto de gel de Aloe vera, como posible agente bacteriostático y/o bactericida sobre Listeria monocytogenes, se determinó la concentración mínima inhibitoria (CMI), el tiempo mínimo de inhibición (TMI) y la concentración bactericida mínima (CBM) de soluciones de extracto de gel de Aloe vera en diferentes concentraciones sobre cultivos de Listeria monocytogenes ATCC 7635. Se aplicó el método de difusión en agar, utilizando soluciones del extracto de gel de Aloe vera en concentraciones de 0 a 100% para la CMI. El TMI se determinó por curvas de crecimiento en caldo Soya tripticasa con un inoculo inicial de Listeria monocytogenes ATCC 7635 de 108 UFC por mL en cada solución. Se pudo determinar que la CMI fue del 10% de extracto de gel de Aloe vera y el TMI fue de 5 horas en las concentraciones de 10%, 20% y 30% de Aloe vera, mientras que a las concentraciones de 50, 80, 90 y 100%, el tiempo fue de 8 horas. Se comprobó que efectivamente el gel de Aloe vera tiene poder bacteriostático sobre Listera monocytogenes (p<0.001), mas sin embargo, no se obtuvo un efecto bactericida en los ensayos realizados.

Bacteriostatic and/or bactericidal extract of Aloe vera gel on cultures of Listeria monocytogenes. Listeria monocytogenes is a bacteria responsible for food borne diseases (FBD) The effect of Aloe vera gel extract as a possible bacteriostatic and / or bactericidal against Listeria monocytogenes, was checked by determined the minimum inhibitory concentration (MIC), the time of minimum inhibition (TMI) and minimum bactericidal concentration (MBC) solutions extract of Aloe vera gel in different concentrations on cultures of Listeria monocytogenes ATCC 7635. We applied the agar diffusion method, using solutions of extract of Aloe vera gel at concentrations of 0 to 100% for the MIC. The TMI was determined by growth curves in trypticase soy broth with an initial inoculum of Listeria monocytogenes ATCC 7635 of 108 CFU/mL in each solution. It was determined that the MIC was 10% extract of Aloe vera gel and TMI was 5 hours at concentrations of 10%, 20% and 30% of Aloe vera, while concentrations of 50, 80, 90 and 100%, the time was 8 hours. It was found that indeed the Aloe vera gel is bacteriostatic power on Listeria monocytogenes (p <0.001), but yet, no bactericidal effect was obtained in our study.

[Bacteriostatic and/or bactericidal extract of Aloe vera gel on cultures of Listeria monocytogenes]. / Efecto bacteriostático y/o bactericida del extracto de gel de Aloe vera sobre cultivos de Listeria monocytogenes.

Listeria monocytogenes is a bacteria responsible for food borne diseases (FBD). The effect of Aloe vera gel extract as a possible bacteriostatic and/or bactericidal against Listeria monocytogenes, was checked by determined the minimum inhibitory concentration (MIC), the time of minimum inhibition (TMI) and minimum bactericidal concentration (MBC) solutions extract of Aloe vera gel in different concentrations on cultures of Listeria monocytogenes ATCC 7635. We applied the agar diffusion method, using solutions of extract of Aloe vera gel at concentrations of 0 to 100% for the MIC. The TMI was determined by growth curves in trypticase soy broth with an initial inoculum of Listeria monocytogenes ATCC 7635 of 108 CFU/mL in each solution. It was determined that the MIC was 10% extract of Aloe vera gel and TMI was 5 hours at concentrations of 10%, 20% and 30% of Aloe vera, while concentrations of 50, 80, 90 and 100%, the time was 8 hours. It was found that indeed the Aloe vera gel is bacteriostatic power on Listeria monocytogenes (p < 0.001), but yet, no bactericidal effect was obtained in our study.

Detección de Listeria monocytogenes en queso blanco criollo, mediante la reacción en cadena de la polimerasa (PCR) / Detection of Listeria monocytogenes in white cheese by Polymerase Chain Reaction (PCR)

La reacción en cadena de la polimerasa, conocida como PCR, es un método que permite replicar miles de veces, en pocas horas e in vitro, pequeñas cantidades de ADN. La aplicación de métodos rápidos y sensibles, para detectar Listeria monocytogenes en muestras de queso blanco, permitirá un mejor control microbiológico del proceso de producción. Se aplicó PCR a 30 muestras de queso blanco, de una quesera de Valencia Estado Carabobo. Se detectó especificidad y sensibilidad para PCR mediante el empleo de la cepa control Listeria monocytogenes 446. Extracción de ADN según metodología descrita por Torres y col., Marcador de peso molecular de 100 pares de base. Se emplearon: cuatro cebadores del gen hlyA de listeriolisina O; iniciadores L1/U1 para banda 938 pb y LF/LR para banda 750 pb del gen hlyA. Estadístico EpiInfo V6 para concordancia de observaciones en geles, mediante coeficiente Kappa (K). Resultados: 8 de las 30 muestras de queso analizadas, mostraron crecimiento presuntivo de Listeria spp en Agar PALCAM. De las cuales 2 de las muestras no pertenecian al género Listeria; en las 6 restantes las pruebas de confirmación arrojaron que: 2 eran L. monocytogenes, 3 L.ivanovii y 1 L. seeligeri. Mediante PCR 2 muestras resultaron positivas para L. monocytogenes al amplificar la banda 938 pb para Listeria y banda 750 pb para la especie monocytogenes. Se concluye que PCR demostró ser altamente específico y sensible para L. monocytogenes, teniendo ventaja sobre agar PALCAM al evidenciar la presencia especifica del patógeno en un tiempo relativamente corto.

The Polymerase Chain Reaction, known as PCR, is a method to replicate thousands of times within a few hours and in vitro, small amounts of DNA. The application of rapid and sensitive methods to detect Listeria monocytogenes in cheese samples, allow a better microbiological control of the production process. PCR was applied to 30 samples of of white cheese, from Valencia, Carabobo State. It was detected PCR specificity and sensitivity by using the control strain Listeria monocytogenes 446. DNA extraction according to the methodology described by Torres et al., Molecular weight marker 100 base pairs. Were used: four primers hlyA gene of listeriolysin O; L1/U1 primers for 938 bp band and LF / LR 750 bp band hlyA gene. EpiInfo Statistical V6 to match observations in gels, by Kappa coefficient (K). Results: 8 out of 30 cheese samples analyzed showed presumptive growth of Listeria spp in PALCAM Agar. Two of the samples not belonged to the genus Listeria, in the 6 remaining sample confirmation tests showed that: 2 were L. monocytogenes, 3 L. ivanovii and 1 L. seeligeri. In PCR 2 samples were positive for L. monocytogenes by amplify the 938 bp band for Listeria and 750 bp band for the species monocytogenes. We concluded that PCR was highly specific and sensitive to L. monocytogenes, taking advantage of PALCAM agar to detect the presence of the pathogen specifies a relatively short time.

[Detection of Listeria monocytogenes in white cheese by polymerase chain reaction (PCR)]. / Detección de listeria monocytogenes en queso blanco criollo, mediante la reacción en cadena de la polimerasa (PCR).

UNLABELLED: The polymerase chain reaction, known as PCR, is a method to replicate thousands of times within a few hours and in vitro, small amounts of DNA. The application of rapid and sensitive methods to detect Listeria monocytogenes in cheese samples, allow a better microbiological control of the production process. PCR was applied to 30 samples of of white cheese, from Valencia, Carabobo State. It was detected PCR specificity and sensitivity by using the control strain Listeria monocytogenes 446. DNA extraction according to the methodology described by Torres et al., Molecular weight marker 100 base pairs. Were used: four primers hlyA gene of listeriolysin O; L1/U1 primers for 938 bp band and LF/LR 750 bp band hlyA gene. Epilnfo Statistical V6 to match observations in gels, by Kappa coefficient (K). RESULTS: 8 out of 30 cheese samples analyzed showed presumptive growth of Listeria spp in PALCAM Agar. Two of the samples not belonged to the genus Listeria, in the 6 remaining sample confirmation tests showed that: 2 were L. monocytogenes, 3 L. ivanovii and 1 L. seeligeri. In PCR 2 samples were positive for L. monocytogenes by amplify the 938 bp band for Listeria and 750 bp band for the species monocytogenes. We concluded that PCR was highly specific and sensitive to L. monocytogenes, taking advantage of PALCAM agar to detect the presence of the pathogen specifies a relatively short time.

[Prevalence of Listeria monocytogenes in fresh tomatoes (Lycopersicum esculentum) and coriander (Coriandrum sativum) in three markets of Valencia, Venezuela]. / Frecuencia de Listeria monocytogenes en muestras de tomates (Lycopersicum esculentum) y cilantro (Coriandrum sativum) frescos en tres supermercados de Valencia, Venezuela.

The incidence of L. monocytogenes in tomatoes and coriander obtained from three different markets, during eight weeks were determined. 192 samples were evaluated: 96 of tomatoes, and 96 of coriander. The isolation of L. monocytogenes was performed using COVENIN 3718:2001. The data were analyzed by SPSS version 12.0. Kolmogorov Smirnov, Mann Whitney U, Kruskal Wallis U test; Spearman's correlation were applied, and p<0.05 significance level was aplied. It was not found significant differences between the medias values and standard deviations of Most Probable Number (MPN) of Listeria spp to tomatoes and coriander during the eight weeks of recollection in the markets; neither between the distributions of MPN of tomatoes and coriander from the markets (Chi2=5,233 p<0,073; Chi2=1,624 p<0,444 respectively) neither the samples per weeks (Chi2=6,547 p<0,477; Chi2=2,667 p<0,914 respectively). In the number of MPN between tomatoes and coriander both distributions were significant different according to test U Mann Whitney U=3040,5 (Z=-4,216 p<0,0001). It was found statistical significance (p<0,001) between the number of MPN of tomatoes and coriander. The presence of Listeria spp in tomatoe was 41,66% (25,0% L. monocytogenes and 16,7% L. ivanovii); in coriander 77,08% (36,5% L. monocytogenes, 33,3% L. ivanovii and 7,3% L. seelige). We concluded that the high level of L. monocytogenes in tomatoes and coriander is independent of the markets store; we see the necessity of a microbiological control on the irrigation system, collection and distribution to ensure the quality of the product.

Frecuencia de listeria monocytogenes en muestras de tomates (lycopersicum esculentum) y cilantro (coriandrum sativum) frescos en tres supermercados de Valencia, Venezuela / Prevalence of listeria monocytogenes in fresh tomatoes (lycopersicum esculentum) and coriander (coriandrum sativum) in three markets of Valencia, Venezuela

Se determinó la frecuencia de L. monocytogenes en tomates y cilantro, de tres diferentes supermercados, ubicados en el Municipio Valencia, Estado Carabobo, durante ocho semanas. Se evaluaron 192 muestras: 96 de tomates y 96 de cilantro. Procesamiento y análisis microbiológico, según Normas Industriales COVENIN 3718:2001. Paquete estadístico SPSS versión 12.0. Se aplicó prueba de Kolmogorov Smirnov, test de U Mann Whitney y Kruskal Wallis y correlación de Spearman. Nivel de significancia (pListeria spp para tomates y cilantro, durante las ocho semanas de recolección en los tres supermercados; ni tampoco entre las distribuciones de NMP en tomates y cilantro de los tres supermercados (Chi²=5,233 p2=1,624 p2=6,547 p2=2,667 pListeria spp en tomate fue 41,66 por ciento (25,0 por ciento L. monocytogenes y 16,7 por ciento L. ivanovii); en cilantro 77,08 por ciento (36,5 por ciento L. monocytogenes, 33,3 por ciento L. ivanovii, 7,3 por ciento L. seeligeri). Se concluye que el elevado porcentaje encontrado de L. monocytogenes en tomates y cilantro, es independiente del supermercado de expendio; se evidencia la necesidad de un control microbiológico a nivel del sistema de riego, recolección y distribución, para asegurar la calidad del producto.

The incidence of L. monocytogenes in tomatoes and coriander obtained from three different markets, during eight weeks were determined. 192 samples were evaluated: 96 of tomatoes, and 96 of coriander. The isolation of L. monocytogenes was performed using COVENIN 3718:2001. The data were analyzed by SPSS version 12.0. Kolmogorov Smirnov, Mann Whitney U, Kruskal Wallis U test; Spearman’s correlation were applied, and pListeria spp to tomatoes and coriander during the eight weeks of recollection in the markets; neither between the distributions of MPN of tomatoes and coriander from the markets (Chi²=5,233 p2=1,624 p2=6,547 p2=2,667 pL. monocytogenes and 16,7 percent L. ivanovii); in coriander 77,08 percent (36,5 percent L. monocytogenes, 33,3 percent L. ivanovii and 7,3 percent L. seelige.). We concluded that the high level of L. monocytogenes in tomatoes and coriander is independent of the markets store; we see the necessity of a microbiological control on the irrigation system, collection and distribution to ensure the quality of the product.