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1.
Sensors (Basel) ; 23(9)2023 Apr 29.
Artículo en Inglés | MEDLINE | ID: mdl-37177600

RESUMEN

The present work developed an electrochemical genosensor for the detection of virulence outer membrane protein A (ompA, tDNA) gene of Cronobacter sakazakii (C. sakazakii) by exploiting the excellent glucose-oxidase-mimicking activity of copper Metal-organic frameworks (Cu-MOF) doped with gold nanoparticle (AuNPs). The signal nanotags of signal probes (sDNA) that biofunctionalized AuNPs@Cu-MOF (sDNA-AuNPs@Cu-MOF) were designed using an Au-S bond. The biosensor was prepared by immobilization capture probes (cDNA) onto an electrodeposited AuNPs-modified glassy carbon electrode (GCE). AuNPs@Cu-MOF was introduced onto the surface of the GCE via a hybridization reaction between cDNA and tDNA, as well as tDNA and sDNA. Due to the enhanced oxidase-mimicking activity of AuNPs@Cu-MOF to glucose, the biosensor gave a linear range of 1.0 × 10-15 to 1.0 × 10-9 mol L-1 to tDNA with a detection limit (LOD) of 0.42 fmol L-1 under optimized conditions using differential pulse voltammetry measurement (DPV). It can be applied in the direct detection of ompA gene segments in total DNA extracts from C. sakazakii with a broad linear range of 5.4-5.4 × 105 CFU mL-1 and a LOD of 0.35 CFU mL-1. The biosensor showed good selectivity, fabricating reproducibility and storage stability, and can be used for the detection of ompA gene segments in real samples with recovery between 87.5% and 107.3%.


Asunto(s)
Técnicas Biosensibles , Cronobacter sakazakii , Nanopartículas del Metal , Estructuras Metalorgánicas , Estructuras Metalorgánicas/química , Oro/química , Cobre/química , ADN Complementario , Glucosa Oxidasa , Reproducibilidad de los Resultados , Límite de Detección , Nanopartículas del Metal/química , Carbono/química , Glucosa , Técnicas Electroquímicas , Electrodos
2.
J Dairy Sci ; 106(6): 3827-3837, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-37105876

RESUMEN

This research aimed to disclose the antibacterial activity of beetroot extract (Beta vulgaris) against Cronobacter sakazakii and its possible mechanisms. We evaluated its antibacterial activity by measuring the minimum inhibitory concentration (MIC) and time-kill kinetics. We also evaluated the intracellular ATP levels, bacterial apoptosis-like death (ALD), and reactive oxygen species (ROS) levels to reveal the possible antibacterial mechanisms. Our results showed that the MIC of beetroot extract against C. sakazakii was 25 mg/mL and C. sakazakii (approximately 8 log cfu/mL) was completely inhibited after treatment with 2 MIC of beetroot extract for 3 h. Beetroot extract reduced intracellular ATP levels and facilitated characteristics of ALD in C. sakazakii, such as membrane depolarization, increased intracellular Ca2+ levels, phosphatidylserine externalization, caspase-like protein activation, and DNA fragmentation. Additionally, and different from most bacterial ALD caused by the accumulation of ROS, beetroot extract reduced the intracellular ROS levels in C. sakazakii. Our experimental data provide a rationale for further research of bacterial ALD and demonstrate that beetroot extract can inhibit C. sakazakii in food processing environments.


Asunto(s)
Beta vulgaris , Cronobacter sakazakii , Cronobacter , Animales , Especies Reactivas de Oxígeno/metabolismo , Beta vulgaris/metabolismo , Antibacterianos/farmacología , Antibacterianos/metabolismo , Bacterias/metabolismo , Apoptosis , Adenosina Trifosfato/metabolismo , Fórmulas Infantiles/microbiología , Microbiología de Alimentos
3.
Food Microbiol ; 65: 254-263, 2017 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-28400011

RESUMEN

Cronobacter sakazakii and Escherichia coli O157:H7 are well known food-borne pathogens that can cause severe disease. The identification of new alternatives to heating to control these pathogens in foods, while reducing the impact on organoleptic properties and nutritional value, is highly desirable. In this study, nisin and its bioengineered variants, nisin V and nisin S29A, are used alone, or in combination with plant essential oils (thymol, carvacrol and trans-cinnamaldehyde) or citric acid, with a view to controlling C. sakazakii and E. coli O157:H7 in laboratory-based assays and model food systems. The use of nisin variants (30 µM) with low concentrations of thymol (0.015%), carvacrol (0.03%) and trans-cinnamaldehyde (0.035%) resulted in extended lag phases of growth compared to those for corresponding nisin A-essential oil combinations. Furthermore, nisin variants (60 µM) used in combination with carvacrol (0.03%) significantly reduced viable counts of E. coli O157:H7 (3-log) and C. sakazakii (4-log) compared to nisin A-carvacrol treatment. Importantly, this increased effectiveness translated into food. More specifically, sub-inhibitory concentrations of nisin variants and carvacrol caused complete inactivation of E. coli O157:H7 in apple juice within 3 h at room temperature compared to that of the equivalent nisin A combination. Furthermore, combinations of commercial Nisaplin and the food additive citric acid reduced C. sakazakii numbers markedly in infant formula within the same 3 h period. These results highlight the potential benefits of combining nisin and variants thereof with carvacrol and/or citric acid for the inhibition of Gram negative food-borne pathogens.


Asunto(s)
Ácido Cítrico/farmacología , Cronobacter sakazakii/efectos de los fármacos , Escherichia coli O157/efectos de los fármacos , Conservación de Alimentos/métodos , Conservantes de Alimentos/farmacología , Nisina/análogos & derivados , Aceites de Plantas/farmacología , Acroleína/análogos & derivados , Acroleína/farmacología , Antibacterianos/farmacología , Bioingeniería , Recuento de Colonia Microbiana , Cronobacter sakazakii/crecimiento & desarrollo , Cimenos , Escherichia coli O157/crecimiento & desarrollo , Aromatizantes/farmacología , Microbiología de Alimentos , Jugos de Frutas y Vegetales/microbiología , Humanos , Lactante , Fórmulas Infantiles/microbiología , Malus , Monoterpenos/farmacología , Nisina/química , Nisina/farmacología , Timol/farmacología
4.
Risk Anal ; 37(12): 2360-2388, 2017 12.
Artículo en Inglés | MEDLINE | ID: mdl-28403572

RESUMEN

A probabilistic and interdisciplinary risk-benefit assessment (RBA) model integrating microbiological, nutritional, and chemical components was developed for infant milk, with the objective of predicting the health impact of different scenarios of consumption. Infant feeding is a particular concern of interest in RBA as breast milk and powder infant formula have both been associated with risks and benefits related to chemicals, bacteria, and nutrients, hence the model considers these three facets. Cronobacter sakazakii, dioxin-like polychlorinated biphenyls (dl-PCB), and docosahexaenoic acid (DHA) were three risk/benefit factors selected as key issues in microbiology, chemistry, and nutrition, respectively. The present model was probabilistic with variability and uncertainty separated using a second-order Monte Carlo simulation process. In this study, advantages and limitations of undertaking probabilistic and interdisciplinary RBA are discussed. In particular, the probabilistic technique was found to be powerful in dealing with missing data and to translate assumptions into quantitative inputs while taking uncertainty into account. In addition, separation of variability and uncertainty strengthened the interpretation of the model outputs by enabling better consideration and distinction of natural heterogeneity from lack of knowledge. Interdisciplinary RBA is necessary to give more structured conclusions and avoid contradictory messages to policymakers and also to consumers, leading to more decisive food recommendations. This assessment provides a conceptual development of the RBA methodology and is a robust basis on which to build upon.


Asunto(s)
Fórmulas Infantiles/efectos adversos , Fórmulas Infantiles/microbiología , Leche Humana/química , Leche Humana/microbiología , Simulación por Computador , Cronobacter sakazakii/aislamiento & purificación , Cronobacter sakazakii/patogenicidad , Ácidos Docosahexaenoicos/administración & dosificación , Ácidos Docosahexaenoicos/análisis , Femenino , Contaminación de Alimentos/estadística & datos numéricos , Microbiología de Alimentos/estadística & datos numéricos , Alimentos Fortificados/análisis , Humanos , Lactante , Fórmulas Infantiles/química , Masculino , Modelos Estadísticos , Método de Montecarlo , Bifenilos Policlorados/toxicidad , Medición de Riesgo/estadística & datos numéricos , Diseño de Software
5.
Microbiology (Reading) ; 162(9): 1708-1714, 2016 09.
Artículo en Inglés | MEDLINE | ID: mdl-27460095

RESUMEN

The present study investigated plant extracts for their anti-quorum-sensing (QS) potential to inhibit the biofilm formation in Cronobacter sakazakii strains. The bioassay based on loss of pigment production by Chromobacterium violaceum 026 and Agrobacterium tumefaciens NTL4(pZLR4) was used for initial screening of the extracts. Further, the effect of extracts on the inhibition of QS-mediated biofilm in C. sakazakii isolates was evaluated using standard crystal violet assay. The effect on biofilm texture was studied using SYTO9 staining and light and scanning electron microscopy. Among the tested extracts, Piper nigrum and Cinnamomum verum at 100 ppm resulted in 78 and 68 % reduction in the production of violacein as well as blue-green colour in both biosensor strains. A higher inhibitory activity (>50 %) on biofilm formation in C. sakazakii was observed for Pip. nigrum and Cin. verum, whereas the other extracts possessed moderate (25-50 %) and minimal (<25 %) inhibitory activities. Further, the fluorescent and scanning electron microscopic images indicated a major disruption in the architecture of biofilms of tested strains by Pip. nigrum. This study points to the possibility of using Pip. nigrum and Cin. verum as inhibitor of QS-mediated biofilm formation by C. sakazakii that could be further explored for novel bioactive molecules to limit the emerging infections of C. sakazakii.


Asunto(s)
Biopelículas/efectos de los fármacos , Cronobacter sakazakii/efectos de los fármacos , Extractos Vegetales/farmacología , Plantas/química , Percepción de Quorum/efectos de los fármacos , Cronobacter sakazakii/fisiología , Evaluación Preclínica de Medicamentos
6.
Foodborne Pathog Dis ; 13(4): 196-204, 2016 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-26919471

RESUMEN

Cronobacter sakazakii is an opportunistic pathogen transmitted by food that affects mainly newborns, infants, and immune-compromised adults. In this study, the antibacterial activity of ferulic acid was tested against C. sakazakii strains. Minimum inhibitory concentration of ferulic acid against C. sakazakii strains was determined using the agar dilution method. Changes in intracellular pH, membrane potential and intracellular ATP concentration were measured to elucidate the possible antibacterial mechanism. Moreover, SYTO 9 nucleic acid staining was used to assess the effect of ferulic acid on bacterial membrane integrity. Cell morphology changes were observed under a field emission scanning electron microscope. The minimum inhibitory concentrations of ferulic acid against C. sakazakii strains ranged from 2.5 to 5.0 mg/mL. Addition of ferulic acid exerted an immediate and sustained inhibition of C. sakazakii proliferation. Ferulic acid affected the membrane integrity of C. sakazakii, as evidenced by intracellular ATP concentration decrease. Moreover, reduction of intracellular pH and cell membrane hyperpolarization were detected in C. sakazakii after exposure to ferulic acid. Reduction of green fluorescence indicated the injury of cell membrane. Electronic microscopy confirmed that cell membrane of C. sakazakii was damaged by ferulic acid. Our results demonstrate that ferulic acid has moderate antimicrobial activity against C. sakazakii. It exerts its antimicrobial action partly through causing cell membrane dysfunction and changes in cellular morphology. Considering its antimicrobial properties, together with its well-known nutritional functions, ferulic acid has potential to be developed as a supplement in infant formula or other foods to control C. sakazakii.


Asunto(s)
Antibacterianos/metabolismo , Ácidos Cumáricos/metabolismo , Cronobacter sakazakii/metabolismo , Suplementos Dietéticos , Conservantes de Alimentos/metabolismo , Adenosina Trifosfato/metabolismo , Antibacterianos/farmacología , Membrana Celular/efectos de los fármacos , Membrana Celular/metabolismo , Membrana Celular/ultraestructura , Proliferación Celular/efectos de los fármacos , China , Recuento de Colonia Microbiana , Ácidos Cumáricos/farmacología , Cronobacter sakazakii/efectos de los fármacos , Cronobacter sakazakii/crecimiento & desarrollo , Cronobacter sakazakii/ultraestructura , Farmacorresistencia Bacteriana , Conservantes de Alimentos/farmacología , Humanos , Concentración de Iones de Hidrógeno , Lactante , Alimentos Infantiles/microbiología , Fórmulas Infantiles/microbiología , Líquido Intracelular/efectos de los fármacos , Líquido Intracelular/metabolismo , Potenciales de la Membrana/efectos de los fármacos , Pruebas de Sensibilidad Microbiana , Viabilidad Microbiana/efectos de los fármacos , Microscopía Electrónica de Rastreo , Especificidad de la Especie
7.
J Dairy Sci ; 99(2): 1019-1028, 2016 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-26627860

RESUMEN

This study evaluated the antimicrobial activity of tea polyphenols (TP) against 4 Cronobacter sakazakii strains with different sequence types (ST) isolated from powdered infant formula (PIF). The results showed that in normal saline, 5mg/mL of TP (pH 3.44) could eliminate approximately 7.0 log cfu/mL of C. sakazakii within 1 h; in rehydrated PIF, after acidification with HCl (pH 3.55), TP showed a stronger antibacterial activity compared with the controls (malic acid, ascorbic acid, and citric acid). Further, some differences were obvious in tolerance to TP between C. sakazakii strains with different ST. The tolerance of C. sakazakii CE1 (ST4) to TP was found to be greater than that of the other 3 C. sakazakii strains (ST1, ST8, and ST64). The results of recovered test and transmission electron microscope analysis revealed that the action of TP against C. sakazakii was an irreversible bactericidal process caused by leakage of cytoplasm. Taken together, these results indicated that TP had an effective bactericidal effect against C. sakazakii, and provided a new idea for preventing and inactivating C. sakazakii in PIF.


Asunto(s)
Antibacterianos/farmacología , Camellia sinensis/química , Cronobacter sakazakii/efectos de los fármacos , Cronobacter sakazakii/aislamiento & purificación , Fórmulas Infantiles/microbiología , Polifenoles/farmacología , Animales , Ácido Cítrico , Microbiología de Alimentos , Humanos , Lactante , Polifenoles/química
8.
Foodborne Pathog Dis ; 11(10): 795-7, 2014 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-25062020

RESUMEN

Cronobacter sakazakii and C. malonaticus are opportunistic pathogens that cause infections in children and immunocompromised adults. In the present study, the antibacterial activity of 19 plant-derived compounds, 5 essential oils, and an extract of propolis were assessed against C. sakazakii and C. malonaticus. The effects of most of these antimicrobials have not been reported previously. Both strains were susceptible to thymol, carvacrol, thymoquinone, p-cymene, linalool, camphor, citral, eugenol, and trans-cinnamaldehyde as well as cinnamon, lemongrass, oregano, clove, and laurel essential oils; their minimum inhibitory concentrations varied between 0.1 and 2.0 mg/mL. As an alternative treatment method, vapors of the volatiles were tested as an indirect treatment. Vapors of trans-cinnamaldehyde, eugenol, oregano, and cinnamon essential oils inhibited both tested strains, while vapors of linalool were only active against C. sakazakii. To our knowledge, this study is the first time that the inhibitory activity of the vapors of these compounds and essential oils has been reported against Cronobacter spp.


Asunto(s)
Antibacterianos/farmacología , Cronobacter sakazakii/efectos de los fármacos , Cronobacter/efectos de los fármacos , Aceites Volátiles/farmacología , Aceites de Plantas/farmacología , Acroleína/análogos & derivados , Acroleína/química , Acroleína/farmacología , Monoterpenos Acíclicos , Antibacterianos/química , Benzoquinonas/química , Benzoquinonas/farmacología , Alcanfor/química , Alcanfor/farmacología , Cinnamomum zeylanicum/química , Cymbopogon/química , Cimenos , Relación Dosis-Respuesta a Droga , Eugenol/química , Eugenol/farmacología , Pruebas de Sensibilidad Microbiana , Monoterpenos/química , Monoterpenos/farmacología , Aceites Volátiles/química , Origanum/química , Extractos Vegetales/química , Extractos Vegetales/farmacología , Aceites de Plantas/química , Sesquiterpenos/química , Sesquiterpenos/farmacología , Syzygium/química , Timol/química , Timol/farmacología
9.
Arch Virol ; 159(9): 2253-61, 2014 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-24705602

RESUMEN

Cronobacter sakazakii, an opportunistic pathogen found in milk-based powdered infant formulae, has been linked to meningitis in infants, with high fatality rates. A set of phages from various environments were purified and tested in vitro against strains of C. sakazakii. Based on host range and lytic activity, the T4-like phage vB_CsaM_GAP161, which belongs to the family Myoviridae, was selected for evaluation of its efficacy against C. sakazakii. Galleria mellonella larvae were used as a whole-animal model for pre-clinical testing of phage efficiency. Twenty-one Cronobacter strains were evaluated for lethality in G. mellonella larvae. Different strains of C. sakazakii caused 0 to 98% mortality. C. sakazakii 3253, with an LD50 dose of ~2.0×10(5) CFU/larva (24 h, 37 °C) was selected for this study. Larvae infected with a dose of 5×LD50 were treated with phage GAP161 (MOI=8) at various time intervals. The mortality rates were as high as 100% in the groups injected with bacteria only, compared to 16.6% in the group infected with bacteria and treated with phage. Phage GAP161 showed the best protective activity against C. sakazakii when the larvae were treated prior to or immediately after infection. The results obtained with heat-inactivated phage proved that the survival of the larvae is not due to host immune stimulation. These results suggest that phage GAP161 is potentially a useful control agent against C. sakazakii. In addition, G. mellonella may be a useful whole-animal model for pre-screening phages for efficacy and safety prior to clinical evaluation in mammalian models.


Asunto(s)
Bacteriófagos/crecimiento & desarrollo , Terapia Biológica/métodos , Cronobacter sakazakii/virología , Infecciones por Enterobacteriaceae/microbiología , Lepidópteros/microbiología , Animales , Bacteriófagos/aislamiento & purificación , Modelos Animales de Enfermedad , Infecciones por Enterobacteriaceae/terapia , Larva/microbiología , Myoviridae/crecimiento & desarrollo , Myoviridae/aislamiento & purificación , Análisis de Supervivencia , Resultado del Tratamiento
10.
Food Microbiol ; 39: 127-31, 2014 May.
Artículo en Inglés | MEDLINE | ID: mdl-24387862

RESUMEN

Blueberry juice and blueberry polyphenols reportedly have antimicrobial properties against foodborne pathogens, without much currently known on their effects against Cronobacter sakazakii. This study evaluated the antimicrobial effects of blueberry proanthocyanidins (PAC) and commercial blueberry juice (BJ) against two strains of C. sakazakii, ATCC 29004 and 29544. BJ (pH 2.8), blueberry PAC (5 mg/ml) and controls (phosphate buffered saline (PBS), pH 7.2, and malic acid pH 3.0) were mixed with equal volumes of washed overnight cultures of C. sakazakii and incubated for 30 min, 1 h, 3 h and 6 h at 37°C. Reductions of ∼1 and 1.50 log CFU/ml were obtained for strains 29004 and 29544, respectively after 30 min with BJ or blueberry PAC. Both C. sakazakii strains 29004 and 29544 were reduced to undetectable levels from 8.25 ± 0.12 log CFU/ml and 8.48 ± 0.03 log CFU/ml, respectively with BJ (pH 2.8) or blueberry PAC after 1 h, while malic acid (pH 3.0) showed ∼1.3 log CFU/ml reduction for both strains. Scanning electron microscopy studies showed differences in cell membrane morphology with clumping and formation of blebs of the treated strains compared to untreated controls. These results warrant further in vivo studies with blueberry bioactives to determine potential for preventing and treating C. sakazakii infections.


Asunto(s)
Antibacterianos/farmacología , Arándanos Azules (Planta)/química , Cronobacter sakazakii/efectos de los fármacos , Extractos Vegetales/farmacología , Proantocianidinas/farmacología , Cronobacter sakazakii/crecimiento & desarrollo , Frutas/química
11.
Appl Environ Microbiol ; 80(3): 959-71, 2014 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-24271174

RESUMEN

We present the results of a study using high-throughput whole-transcriptome sequencing (RNA-seq) and vibrational spectroscopy to characterize and fingerprint pathogenic-bacterium injury under conditions of unfavorable stress. Two garlic-derived organosulfur compounds were found to be highly effective antimicrobial compounds against Cronobacter sakazakii, a leading pathogen associated with invasive infection of infants and causing meningitis, necrotizing entercolitis, and bacteremia. RNA-seq shows changes in gene expression patterns and transcriptomic response, while confocal micro-Raman spectroscopy characterizes macromolecular changes in the bacterial cell resulting from this chemical stress. RNA-seq analyses showed that the bacterial response to ajoene differed from the response to diallyl sulfide. Specifically, ajoene caused downregulation of motility-related genes, while diallyl sulfide treatment caused an increased expression of cell wall synthesis genes. Confocal micro-Raman spectroscopy revealed that the two compounds appear to have the same phase I antimicrobial mechanism of binding to thiol-containing proteins/enzymes in bacterial cells generating a disulfide stretching band but different phase II antimicrobial mechanisms, showing alterations in the secondary structures of proteins in two different ways. Diallyl sulfide primarily altered the α-helix and ß-sheet, as reflected in changes in amide I, while ajoene altered the structures containing phenylalanine and tyrosine. Bayesian probability analysis validated the ability of principal component analysis to differentiate treated and control C. sakazakii cells. Scanning electron microscopy confirmed cell injury, showing significant morphological variations in cells following treatments by these two compounds. Findings from this study aid in the development of effective intervention strategies to reduce the risk of C. sakazakii contamination in the food production environment and on food contact surfaces, reducing the risks to susceptible consumers.


Asunto(s)
Compuestos Alílicos/farmacología , Antibacterianos/farmacología , Cronobacter sakazakii/efectos de los fármacos , Disulfuros/farmacología , Ajo/química , Espectrometría Raman , Sulfuros/farmacología , Transcriptoma , Compuestos Alílicos/aislamiento & purificación , Antibacterianos/aislamiento & purificación , Cronobacter sakazakii/ultraestructura , Disulfuros/aislamiento & purificación , Microscopía Electrónica de Rastreo , Conformación Proteica/efectos de los fármacos , Sulfuros/aislamiento & purificación , Sulfóxidos
12.
Food Microbiol ; 36(2): 142-8, 2013 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-24010592

RESUMEN

In the present study, Cronobacter sakazakii, a foodborne pathogen, was first subjected to heat shock at 47 °C for 15 min. Effect of heat shock on the fatty acid and protein profiles, carbon and nitrogen source requirements as well as the susceptibilities of C. sakazakii to Clidox-S, a chlorine-containing disinfectant and Quatricide, a quaternary ammonium compound were investigated. Results revealed that heat shock increased the proportion of myristic acid (14:0), palmitic acid (16:0) and the ratio of saturated fatty acid to unsaturated fatty acid, while reducing the proportion of palmitoleic acid (16:1) and cis-vacceric acid (18:1). In addition, eleven proteins showed enhanced expression, while one protein showed decreased expression in the heat-shocked compared to the non-heat-shocked cells. Non-heat-shocked cells in the medium supplemented with beef extract exhibited the highest maximum population. On the contrary, the highest maximum population of heat-shocked C. sakazakii was noted in the medium having either tryptone or yeast extract as the nitrogen source. Among the various carbon sources examined, the growth of the test organism, regardless of heat shock, was greatest in the medium having glucose as the carbon source. Furthermore, heat shock enhanced the resistance of C. sakazakii to Clidox-S or Quatricide.


Asunto(s)
Proteínas Bacterianas/metabolismo , Carbono/metabolismo , Cronobacter sakazakii/efectos de los fármacos , Cronobacter sakazakii/crecimiento & desarrollo , Desinfectantes/farmacología , Ácidos Grasos/metabolismo , Nitrógeno/metabolismo , Proteínas Bacterianas/genética , Cronobacter sakazakii/genética , Cronobacter sakazakii/metabolismo , Ácidos Grasos/química , Calor , Viabilidad Microbiana/efectos de los fármacos
13.
J Food Sci ; 77(9): M523-7, 2012 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-22900597

RESUMEN

The thermal tolerance Cronobacter sakazakii was examined in sterile powdered infant formula (PIF) rehydrated at 58 °C in water or apple juice supplemented with vanillin, ethyl vanillin, or vanillic acid. All three compounds decreased thermal tolerance during-rehydration and the lowest decimal reduction time (D-value, 0.19 ± 0.01 min) was measured in PIF rehydrated in apple juice supplemented with 20 mM vanillic acid. At this level of supplementation no C. sakazakii were detected in PIF stored for 48 h at 10 and 24 h at 21 °C subsequent to a sublethal heat treatment. Thermal tolerance during rehydration and survival in reconstituted PIF were influenced by compound type, concentration, and temperature. Supplementation of PIF with vanillin, ethyl vanillin, or vanillic acid could enhance the safety of PIF or other dehydrated foods contaminated with C. sakazakii.


Asunto(s)
Benzaldehídos/química , Cronobacter sakazakii/aislamiento & purificación , Fórmulas Infantiles/química , Ácido Vanílico/química , Bebidas , Recuento de Colonia Microbiana , Seguridad de Productos para el Consumidor , Cronobacter sakazakii/crecimiento & desarrollo , Suplementos Dietéticos , Contaminación de Alimentos/análisis , Manipulación de Alimentos/métodos , Microbiología de Alimentos , Humanos , Lactante , Malus/química , Temperatura
14.
J Appl Microbiol ; 110(3): 697-703, 2011 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-21255207

RESUMEN

AIMS: The study aimed to compare survival of Cronobacter sakazakii strains in plant-derived infant milk formula (IMF) ingredients and their thermotolerance in reconstituted IMF. METHODS AND RESULTS: Inulin and lecithin were inoculated with isolates of C. sakazakii including the typed clinical strains, NCTC 11467(T) and BAA 894; a mutant strain in which the wcaD gene had been disrupted; and two environmental strains isolated from IMF processing facilities. Samples were stored and examined for C. sakazakii. All strains were still detectable in both matrices after 338 days storage, except for the mutant strain that was no longer detectable at that time. Higher numbers of the environmental strains were recoverable after 338 days than the clinical strains. The thermotolerance of the five strains was investigated in reconstituted IMF at 55, 60 and 65°C. The clinically derived type strain, NCTC 11467(T), and the mutant strain were shown to be significantly more thermotolerant than other strains tested. CONCLUSIONS: Environmental strains were more persistent than the clinical strains in inulin and lecithin, indicating that patho-adaptation may have contributed to a reduction in the desiccation tolerance phenotype. However, the thermotolerance results could indicate that the ability to produce extracellular polysaccharide decreases thermotolerance. SIGNIFICANCE AND IMPACT OF THE STUDY: These results indicate that desiccation resistance may play a role in survival of C. sakazakii in dry IMF ingredients and processing plants; however, this trait may be of less importance in clinical environs.


Asunto(s)
Cronobacter sakazakii/fisiología , Microbiología de Alimentos , Fórmulas Infantiles , Animales , Recuento de Colonia Microbiana , Cronobacter sakazakii/efectos de los fármacos , Desecación , Infecciones por Enterobacteriaceae/microbiología , Microbiología Ambiental , Calor , Humanos , Lactante , Fórmulas Infantiles/química , Inulina/farmacología , Lecitinas/farmacología , Estrés Fisiológico , Factores de Tiempo
15.
Int J Food Microbiol ; 129(3): 295-9, 2009 Feb 28.
Artículo en Inglés | MEDLINE | ID: mdl-19167124

RESUMEN

Hot and cold water-soluble muscadine (Vitis rotundifolia) seed extracts and their polar and polyphenol fractions from two Muscadine cultivars ('Ison', purple and 'Carlos', bronze) were investigated for their inhibition of Enterobacter sakazakii. The heat treatment on each seed extract not only increased total phenolics and tannic acid but also enhanced antimicrobial activity against two strains of E. sakazakii. Within 1 h, all seed extracts reduced an initial population (approximately 6 log CFU/mL) of E. sakazakii to a non-detectable level (minimum detection limit, 10 CFU/mL). Regardless of extraction method and cultivar, only the polar fractions which contained malic, tartaric and tannic acids showed antimicrobial activity against two strains of E. sakazakii. The polyphenol fractions which contained gallic acid, catechin, epicatechin, ellagic acid and pigments showed slight inhibition against E. sakazakii. Results showed that water-soluble muscadine seed extracts (pH 3.3-3.78) contained strong antimicrobial inhibitors against E. sakazakii while acidified peptone water (pH 3.3) did not show any antimicrobial activity.


Asunto(s)
Antibacterianos/farmacología , Cronobacter sakazakii/efectos de los fármacos , Extractos Vegetales/farmacología , Semillas/química , Vitis/química , Agua/química , Antibacterianos/química , Cromatografía Líquida de Alta Presión , Concentración de Iones de Hidrógeno , Hidroxibenzoatos/química , Fenoles/química , Extractos Vegetales/química
16.
J Food Sci ; 74(9): M479-84, 2009.
Artículo en Inglés | MEDLINE | ID: mdl-20492118

RESUMEN

Cronobacter is a new genus containing 5 species previously known as Enterobacter sakazakii. The popularity of "natural" substances and alternative medicine has extended the use of natural antimicrobials and herbs to foods, and some herbs are claimed to relieve gastric disturbances in infants. The present study investigated the antimicrobial activity of bovine lactoferrin (LF) and Cronobacter survival in commercial herbal infant teas (HITs) reconstituted with water at different temperatures. Cronobacter cells were able to grow in all reconstituted HITs at 37 or 21 degrees C after 6 h. A 4-log reduction in Cronobacter was achieved by reconstituting herbal infant tea at > or = 60 degrees C. LF was able to reduce Cronobacter species viability in herbal infant tea. No viable cells were recovered after 4 h at 37 degrees C in the presence of > or = 5 mg LF/mL. The bactericidal activity of LF was reduced at lower concentrations and lower temperatures. This study demonstrates that if present in reconstituted herbal infant tea, Cronobacter can grow and this may compromise the safety of these products. Therefore, addition of LF to reconstituted HIT may be a promising approach for the effective control of this organism. Practical Application: Cronobacter species can be isolated from herbal teas, and these products are claimed to relieve gastric disturbances in infants. This study demonstrates that Cronobacter cells present in reconstituted herbal infant teas (HITs) can grow if not held at acceptable temperatures. It was shown that reconstitution of these tea formulas with > or = 60 degrees C water reduced the potential risk from Cronobacter. Furthermore, use of lactoferrin (LF) may be a promising approach for effective control of these organisms in HIT held at nonrefrigeration temperatures (10 to 37 degrees C) for short periods.


Asunto(s)
Antibacterianos/farmacología , Bebidas/microbiología , Cronobacter sakazakii/efectos de los fármacos , Cronobacter sakazakii/crecimiento & desarrollo , Microbiología de Alimentos , Alimentos Infantiles/microbiología , Lactoferrina/farmacología , Bebidas/análisis , Calcio de la Dieta/análisis , Recuento de Colonia Microbiana , Conservantes de Alimentos/farmacología , Enfermedades Transmitidas por los Alimentos/prevención & control , Calor , Humanos , Lactante , Alimentos Infantiles/análisis , Hierro de la Dieta/análisis , Magnesio/análisis , Viabilidad Microbiana/efectos de los fármacos , Proteínas de la Leche/farmacología , Concentración Osmolar , Fitoterapia , Factores de Tiempo
18.
Lett Appl Microbiol ; 47(4): 315-21, 2008 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-19241526

RESUMEN

AIM: To determine the antimicrobial activity of natural organic compounds alone and in combination with nisin on the growth of Enterobacter sakazakii in laboratory media. METHODS AND RESULTS: The minimum inhibitory concentrations (MIC) of five natural organic compounds were determined, and their effects in combination with nisin were evaluated by comparing treatment with each natural organic compound alone and in combination with 25 mg ml(-1) nisin in tryptic soy broth. Among the tested natural organic compounds, the MIC of carvacrol and thymol was 125 mmol l(-1) and showed the strongest inhibitory activity against E. sakazakii, whereas the MIC of cinnamic acid was higher than 5 mmol l(-1), and therefore showed the weakest inhibitory activity. However, the combination of each compound with nisin did not result in the enhancement of their antimicrobial activities except when nisin was combined with diacetyl. CONCLUSIONS: The order of inhibition attributed to natural organic compounds was carvacrol = thymol > eugenol > diacetyl > cinnamic acid, and only the combination of diacetyl and nisin showed a synergistic effect of inhibiting the growth of E. sakazakii. SIGNIFICANCE AND IMPACT OF THE STUDY: This study shows the potential of natural organic compounds for controlling E. sakazakii.


Asunto(s)
Antibacterianos/farmacología , Cronobacter sakazakii/efectos de los fármacos , Nisina/farmacología , Extractos Vegetales/farmacología , Cinamatos/farmacología , Cimenos , Diacetil/farmacología , Sinergismo Farmacológico , Quimioterapia Combinada , Eugenol/farmacología , Pruebas de Sensibilidad Microbiana , Monoterpenos/farmacología , Timol/farmacología
19.
Breastfeed Med ; 2(4): 205-8, 2007 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-18081457

RESUMEN

OBJECTIVES: To compare the effects of a human breastmilk-derived fortifier on the antibacterial activity of milk obtained from lactating mothers delivering prematurely with the effects of a powdered fortifier on the same milk. STUDY DESIGN: Human milk samples were obtained after the first week of postnatal life from 10 lactating mothers, who had delivered prematurely. A bovine milk-based powdered fortifier and a human breastmilk-based frozen fortifier were evaluated. All mothers were healthy and they were not on any medications, although they were taking prenatal vitamins during lactation. The effects of each fortifier on the antimicrobial activity of milk toward Enterobacter sakazaki (ES), Escherichia coli, Clostridium difficile (CD), and Shigella soneii (SS) were evaluated by both the filter paper method and the growth inhibition method. RESULTS: Human milk inhibited the growth of all of the test organisms. This antibacterial activity was almost totally inhibited by the addition of the bovine protein-based human milk fortifier, while it remained unaffected by the addition of the human breastmilk-based fortifier. CONCLUSIONS: Breastmilk from women who have delivered preterm has antibacterial activity that can be affected by the addition of bovine-based fortifier, but not by the addition of a human breastmilk-based fortifier.


Asunto(s)
Alimentos Fortificados , Fórmulas Infantiles/química , Recien Nacido Prematuro , Proteínas de la Leche/farmacología , Leche Humana/inmunología , Animales , Bovinos , Clostridioides difficile/crecimiento & desarrollo , Cronobacter sakazakii/crecimiento & desarrollo , Escherichia coli/efectos de los fármacos , Femenino , Humanos , Lactante , Recién Nacido , Masculino , Leche/inmunología , Shigella sonnei/crecimiento & desarrollo
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