Biological control of foodborne pathogens by lacticacid bacteria: A focus on juice processing industries

Abstract The use of lactic acid bacteria (LAB) in foods as biocontrol agents against foodborne pathogens has become increasingly known. Under the premise that controlling the adhesion of microorganisms to food contact surfaces is an essential step for meeting the goals of food processing, the aim of this work was to investigate the inhibitory and anti-biofilm effectiveness of Lactobacillus rhamnosus GG (ATCC 53103) and Lactobacillus casei (ATCC 393) against Escherichia coli O157:H7, Salmonella enterica and Listeria monocytogenes. Lactobacillus strains (108UFCCFU/ml) and pathogens (104UFCCFU/ml) were evaluated to monitor LAB anti-adhesive and antibiofilm effect, in two main scenarios: (i) co-adhesion and (ii) pathogen incorporation to stainless steel surfaces with a protective biofilm of Lactobacillus cells. In (i) the predominant effect was observed in L. rhamnosus against S. enterica and L. monocytogenes, whereas in (ii) both LAB significantly reduced the number of pathogenic adherent cells. The effect of pre-established LAB biofilms was more successful in displacing the three pathogens than when they were evaluated under co-adhesion. These findings show that both LAB can be considered good candidates to prevent or inhibit the adhesion and colonization of L. monocytogenes, S. enterica and E. coli O157:H7 on surfaces and conditions of relevance for juice processing industries, offering alternatives for improving the safety and quality of fruit-based products.

Resumen Existe un creciente interés en el uso de bacterias ácido lácticas (BAL) como agentes de biocontrol frente a patógenos de transmisión alimentaria. Bajo la premisa de que el control de la adhesión de microorganismos a superficies de contacto con alimentos es el paso esencial para evitar su contaminación, el objetivo de este trabajo fue investigar la efectividad inhibitoria y antibiofilm de Lactobacillus rhamnosus GG (ATCC 53103) y Lactobacillus casei (ATCC 393) frente a Escherichia coli O157:H7, Salmonella enterica y Listeria monocytogenes. A fin de cumplir con el objetivo propuesto, las cepas de Lactobacillus (108UFCUFC/ml) y los patógenos (104UFCUFC/ml) se ensayaron en 2 escenarios: (1) coadhesión, y (2) incorporación de los patógenos a las superficies de acero inoxidable con un biofilm preformado de Lactobacillus. En (1), el efecto predominante se observó con L. rhamnosus frente a S. enterica y L. monocytogenes, mientras que en (2), ambas BAL redujeron significativamente el número de células patógenas adheridas. En función de estos resultados, concluimos que el efecto de un biofilm preformado de ambas BAL fue más exitoso en el desplazamiento de los 3 patógenos que en coadhesión. Ambas BAL pueden considerarse buenas candidatas para mitigar la adhesión y colonización de L. monocytogenes, S. enterica y E. coli O157:H7 en superficies en condiciones de relevancia para la industria procesadora de jugos, y, de esta manera, ofrecer alternativas para mejorar la seguridad y calidad de los alimentos a base de frutas.

Grape juice increases the BDNF levels but not alter the S100B levels in hippocampus and frontal cortex from male Wistar Rats

ABSTRACT Several studies have shown that a high consumption of vegetables and fruits is consistently associated with a low risk of oxidative stress-induced diseases, which includes some degenerative diseases such as amyotrophic lateral sclerosis, Alzheimer and Parkinson. Therefore, the objective of this study is to verify the effects of conventional and organic grape juice in the modulation of the neurotrophic factor (BDNF) and astrocytic markers protein (S100B) in hippocampus and frontal cortex of Wistar rats. In this study, 24 male Wistar rats were divided into three groups. To the first one, it was given organic purple grape juice; to the second, conventional grape juice, while the last one received only saline. After 30 days, all rats were sacrificed and hippocampus and frontal cortex were dissected. The animals that received organic and conventional grape juice showed, in frontal cortex, an elevated BNDF levels in relation to saline group. However, S100B levels did not change. These results showed that grape juices are able to modulate important marker in brain tissue, and could be an important factor to prevent brain diseases.

Effect of different presentations of resveratrol on cell proliferation and epitelial thickness of the oral mucosa of wistar rats

Introduction: Grape is one of the most important fruit crops across the world and can be consumed in different ways. There has been a growing interest in the role of antioxidants such as resveratrol, which can be found in grape skin, in oral and dental tissues. Thus, the objective of this study was to analyze the effect of different presentations of resveratrol on cell proliferation and epithelial thickness of the oral mucosa of Wistar rats. Methods: Fifty male Wistar rats were randomly divided into five groups: water/control, red wine, grape juice, 12% alcoholic solution/ethanol and aqueous solution of resveratrol. Samples of palatal and tongue mucosa were collected for a histomorphometric analysis using hematoxylin-eosin staining and the argyrophilic nucleolar organizer region (AgNOR) technique for quantification of cell proliferation. Results: As to epithelial thickness, both the tongue and the palate showed a statistically significant difference between the control group and the other groups, with greater decrease in the resveratrol and the wine groups. In the suprabasal layer of both the tongue and the palate epithelium, red wine reduced the rate of cell proliferation, while ethanol increased it. In the basal layer of the tongue epithelium, there was a statistically significant difference between the control, the grape juice and the resveratrol groups and the ethanol group, with increased cell proliferation in the ethanol group. Conclusions: Wine does not interfere in the physiological renewal of the basal layer of the buccal epithelium and exerts a protective action by reducing the cell proliferation rate of the suprabasal layer (AU)

Determination of As (III) and As (V) in grape juice samples by differential pulse cathodic stripping voltammetry

This study describes a simple and sensitive voltammetric method for determining As (III) and As (V)concentrations in ìg.L-1. Electroactive As (III) is evaluated by direct analysis. As (V) is converted into As (III) using reduction solution; the new As (III) concentration, represents the total inorganic As in the analyzed sample. As (III) and total inorganic As determination showed a work potential peak at -0.68 V;As (V) concentration was determined by subtraction [total inorganic As – As (III)]. Quantification and detection limits for As (III) were 0.22 and 0.08 ìg.L-1, respectively, for a deposition time of 180 s with the linear range from 1 to 5 ìg.L-1. Standard deviation for 1 to 5 ìg.L-1 arsenic concentration (n = 10) was 5%.The methodology was successfully applied for identifying and quantifying the inorganic arsenic in grape juices; and the accuracy was assessed by a recovery test on spiked samples, being 98.2% for As (III) and 96.4% for As (V). These results were compared with those from hydride generation atomic absorptions pectrometry analyses. The grape juice samples analyzed by voltammetric technique showed As (III) and As (V) concentrations ranging 51-71 ìg.L-1 and 34-60 ìg.L-1, respectively.

Aquecimento de vinho tinto e suco de uva utilizados em preparações culinárias não afeta a capacidade antioxidante e o teor de fenóis totais / Heating of red wine and grape juice in food preparations does not affect their antioxidant capacity and total phenol content

OBJETIVO: Avaliar a capacidade antioxidante e a concentração dos compostos fenólicos de vinho tinto e suco de uva utilizados em preparações culinárias, quando submetidos ao processo de fervura. Métodos: A avaliação ocorreu após diferentes períodos de aquecimento (100ºC) em dois sistemas: i) panela de alumínio e chama de fogão e ii) balão de vidro e manta térmica. Amostras comerciais de vinho tinto (n=4) e suco de uva integral (n=4) foram submetidas à fervura por 10, 20 e 60 minutos. Antes e após cada período de fervura, a capacidade antioxidante total foi avaliada pela medida do potencial redutor férrico, e o teor de fenóis totais foi quantificado pelo método de Folin-Ciocalteau. As diferenças foram comparadas pela análise de variância para medidas repetidas (p<0,05). Resultados: A fervura durante os diferentes períodos de tempo não provocou variações importantes na capacidade antioxidante total e no teor de fenóis totais das bebidas, independentemente do sistema de aquecimento utilizado. Conclusão: De acordo com os resultados obtidos, as propriedades antioxidantes do vinho tinto e do suco de uva, quando submetidos à fervura por até 60 minutos, mantiveram-se relativamente estáveis.

Objective: This study evaluated the antioxidant capacity and concentration of phenolic compounds in red wine and grape juice used in culinary preparations subjected to boiling. Methods: The assessments were done after different boiling times (100ºC) using two systems: i) aluminum pot and stove flame and ii) volumetric flask and heating mantle. Samples of red wine (n=4) and grape juice (n=4) were subjected to boiling for 10, 20 and 60 minutes. Before and after each boiling period, the total antioxidant capacity was evaluated by the ferric reducing antioxidant power assay and the total phenol content was determined by the Folin-Ciocalteu reagent. Differences were compared by repeated measures analysis of variance (RM-ANOVA) (p<0.05). Results: The different boiling times did not cause significant changes in the total antioxidant capacity or total phenol content of the beverages, regardless of boiling method. Conclusion: The results show that the antioxidant properties of red wine and grape juice did not change significantly after boiling for 60 minutes.

Caracterização de diferentes marcas de sucos de uva comercializados em duas regiões do Brasil / Characterization of different trading marks of grape juice in two regions of Brazil

Objetivou-se com este trabalho foi avaliar três marcas de diferentes sucos de uva integral (Vitis labrusca L.) oriundos de duas regiões do Brasil (Sudeste e Centro-Oeste). Os sucos foram avaliados quanto às seguintes análises: sólidos solúveis (°Brix), acidez titulável (AT), pH, vitamina C, açúcares redutores, totais e não-redutores. Os resultados indicaram variabilidade entre as diferentes marcas de sucos de uva, evidenciando que estas encontram-se fora dos padrões estabelecidos pela legislação brasileira em vigor. De acordo com os elevados valores de açúcares totais e não redutores, pode-se inferir que houve adição de sacarose nas três marcas dos sucos analisados.

The purpose of this work was to evaluated three different marks of juice of integral grape (Vitis labrusca L.) originating from two regions of Brazil (Southeast and Center-west). The juices had been evaluated as the following analyses: soluble solids (ºBrix), titratable acidity (AT), pH, vitamin C, reducing sugars, total and no-reducing sugars. The results indicated variability among the differents marks of grape juice, showing that they find themselves out of the established patterns by the vigorating Brazilian legislation. Acording to the high values of total and non reducing sugars, it may be inferred that there was addition of sucrose in the three analyzed juice marks.

Effect of Maternal Factors on the Concentrations of Minerals and Immunological Substance in Breast Milk

Flavonoids contained in grapes are potent antioxidants that may protect against oxidative stress and reduce the risk of chronic diseases related with free radical damage. In this study we investigated the effect of daily grape juice supplementation on blood pressure (BP), plasma lipid profiles and the generation of free radicals in 67 healthy volunteers (29 smoker, 38 nonsmokers). The daily 480 ml of grape juice supplementation for 8 weeks resulted in a significant decrease in diastolic BP by 6.5% in smokers and systolic and diastolic BP by 11.2 and 3.7% in non-smokers. Plasma total cholesterol, HDL- and LDL-cholesterol levels in smokers and total cholesterol in non-smokers were significantly increased after the intervention. Plasma triglycerides and conjugated dienes were not affected by grape juice supplementation. Levels of free radical determined by reading the lucigenin-perborate ROS generating sources, decreased significantly by 18% compared to the beginning of the study. The results indicated that the consumption of grape juice may reduce BP and free radical generation in smokers, which was possibly exerted by flavonoids. Our findings suggested that the grape juice has protective effect on chronic disease due to the overproduction of free radical in smokers.

EFFECTS OF GRAPE JUICE ON PROLIFERATION AND APOPTOSIS OF HUMAN PROSTATE CARCINOMA PC-3 CELLS / 营养学报

Objectives: To study the inhibitory effects of grape juice on human prostate carcinoma PC-3 cells and its possible mechanism. Method: PC-3 cells were treated with grape juice in different concentration(16, 32, 64 ?l/ml) and resveratrol for 48 h; and the proliferation of PC -3 cells were measured by growth curve and MTT assay. TUNEL was used to observe the morphology of apoptotic cells and flow cytometry to analyze the PC-3 apoptosis. Results: Resveratrol and grape juice could markedly inhibit the proliferation of PC-3 cells, and TUNEL positive cells were detectable. The percentages of apoptotic cells were 6.0%,18.5%,30.0%, 12.7% in experimental groups and resveratrol group respectively. The effect on PC-3 cells was enhanced with increasing amount of grape juice. The effect of low dose group was weaker than that of resveratrol group, but medium and high dose groups were stronger. Conclusion: The anti-prostate cancer effect of grape juice is not only related to resveratrol contained but also to synergism with other components, and its mechanism might be the induction of PC-3 cells apoptosis.

The Effects of Purple Grape Juice Supplementation on Blood Pressure, Plasma Lipid Profile and Free Radical Levels in Korean Smokers

Flavonoids contained in grapes are potent antioxidants that may protect against oxidative stress and reduce the risk of chronic diseases related with free radical damage. In this study we investigated the effect of daily grape juice supplementation on blood pressure (BP), plasma lipid profiles and the generation of free radicals in 67 healthy volunteers (29 smoker, 38 nonsmokers). The daily 480 ml of grape juice supplementation for 8 weeks resulted in a significant decrease in diastolic BP by 6.5% in smokers and systolic and diastolic BP by 11.2 and 3.7% in non-smokers. Plasma total cholesterol, HDL- and LDL-cholesterol levels in smokers and total cholesterol in non-smokers were significantly increased after the intervention. Plasma triglycerides and conjugated dienes were not affected by grape juice supplementation. Levels of free radical determined by reading the lucigenin-perborate ROS generating sources, decreased significantly by 18% compared to the beginning of the study. The results indicated that the consumption of grape juice may reduce BP and free radical generation in smokers, which was possibly exerted by flavonoids. Our findings suggested that the grape juice has protective effect on chronic disease due to the overproduction of free radical in smokers.

The Effects of Purple Grape Juice Supplementation on Improvement of Antioxidant Status and Lymphocyte DNA Damage in Korean Smokers

The purpose of this project was to evaluate whether daily fruit juice consumption could reduce the DNA damage in healthy subjects. The study was performed using 67 healthy volunteers (29 smokers, 38 nonsmokers) who were supplemented with 480 ml of grape juice for 8 weeks. Eight weeks of grape juice consumption did not change any anthropometric parameters. Lymphocyte DNA damage before the study was significantly greater (p < 0.05) in smoker than nonsmoker, but, grape juice consumption significantly reduced DNA damage in both smoker (26%) and nonsmoker (17%) to the level where there was no difference remained between the two groups after the intervention trial. This preventive effect of grape juice against DNA damage was not affected by sex of the subjects in non-smokers. Plasma alpha-carotene, lycopene and gamma-totopherol was significantly increased after the trial in smokers, while erythrocyte catalase was significantly increased in both smokers and nonsmokers. Total radical-trapping antioxidant potential (TRAP) level in all subjects was significantly reduced after the intervention, while GSH-Px activity was increased only in nonsmokers. These results suggests that daily consumption of grape juice may protect DNA damage in peripheral lymphocytes, and supports the hypothesis that grape juice might exert their effect partially via a decrease in oxidative damage to DNA in humans partly by improving their antioxidative defense system.