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BACKGROUND: Statins are widely used for treating patients with ischemic stroke at risk of secondary cerebrovascular events. It is unknown whether Asian populations benefit from more intensive statin-based therapy for stroke recurrence. Therefore, in the present study we evaluated the effectiveness and safety of high-dose and moderate-dose statins for patients who had experienced mild ischemic stroke during the acute period. METHODS AND RESULTS: This multicenter prospective study included patients with mild ischemic stroke who presented within 72 hours of symptom onset. The outcomes of patients in the high-intensity and moderate-intensity statin treatment groups were compared, with the main efficacy outcome being stroke recurrence and the primary safety end point being intracranial hemorrhage. The propensity score matching method was employed to control for imbalances in baseline variables. Subgroup analyses were conducted to evaluate group differences. In total, the data of 2950 patients were analyzed at 3 months, and the data of 2764 patients were analyzed at 12 months due to loss to follow-up. According to the multivariable Cox analyses adjusted for potential confounders, stroke recurrence occurred similarly in the high-intensity statin and moderate-intensity statin groups (3 months: adjusted hazard ratio [HR], 1.12 [95% CI, 0.85-1.49]; P=0.424; 12 months: adjusted HR, 1.08 [95% CI, 0.86-1.34]; P=0.519). High-intensity statin therapy was associated with an increased risk of intracranial hemorrhage (3 months: adjusted HR, 1.81 [95% CI, 1.00-3.25]; P=0.048; 12 months: adjusted HR, 1.86 [95% CI, 1.10-3.16]; P=0.021). The results from the propensity score-matched analyses were consistent with those from the Cox proportional hazards analysis. CONCLUSIONS: Compared with moderate-intensity statin therapy, high-dose statin therapy may not decrease the risk of mild, noncardiogenic ischemic stroke recurrence but may increase the risk of intracranial hemorrhage. REGISTRATION: URL: www.chictr.org.cn/. Unique Identifier: ChiCTR1900025214.
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Inibidores de Hidroximetilglutaril-CoA Redutases , AVC Isquêmico , Recidiva , Humanos , Inibidores de Hidroximetilglutaril-CoA Redutases/uso terapêutico , Inibidores de Hidroximetilglutaril-CoA Redutases/efeitos adversos , Feminino , Masculino , Estudos Prospectivos , AVC Isquêmico/tratamento farmacológico , AVC Isquêmico/epidemiologia , AVC Isquêmico/diagnóstico , Idoso , Pessoa de Meia-Idade , Resultado do Tratamento , Fatores de Tempo , Fatores de Risco , Pontuação de Propensão , Hemorragias Intracranianas/induzido quimicamente , Hemorragias Intracranianas/epidemiologia , Índice de Gravidade de Doença , Prevenção Secundária/métodosRESUMO
Shiga toxin-producing Escherichia coli (STEC) causes a wide spectrum of diseases including hemorrhagic colitis and hemolytic uremic syndrome (HUS). Previously, we developed a rapid, sensitive, and potentially portable assay that identified STEC by detecting Shiga toxin (Stx) using a B-cell based biosensor platform. We applied this assay to detect Stx2 present in food samples that have been implicated in previous STEC foodborne outbreaks (milk, lettuce, and beef). The STEC enrichment medium, modified Tryptone Soy Broth (mTSB), inhibited the biosensor assay, but dilution with the assay buffer relieved this effect. Results with Stx2a toxoid-spiked food samples indicated an estimated limit of detection (LOD) of ≈4 ng/mL. When this assay was applied to food samples inoculated with STEC, it was able to detect 0.4 CFU/g or 0.4 CFU/mL of STEC at 16 h post incubation (hpi) in an enrichment medium containing mitomycin C. Importantly, this assay was even able to detect STEC strains that were high expressors of Stx2 at 8 hpi. These results indicate that the STEC CANARY biosensor assay is a rapid and sensitive assay applicable for detection of STEC contamination in food with minimal sample processing that can complement the current Food Safety Inspection Service (US) methodologies for STEC.
Assuntos
Técnicas Biossensoriais , Microbiologia de Alimentos , Lactuca , Escherichia coli Shiga Toxigênica , Escherichia coli Shiga Toxigênica/isolamento & purificação , Técnicas Biossensoriais/métodos , Lactuca/microbiologia , Contaminação de Alimentos/análise , Leite/microbiologia , Animais , Toxina Shiga II/análise , Toxina Shiga II/genética , Limite de Detecção , Carne Vermelha/microbiologia , BovinosRESUMO
Shiga-toxin-producing Escherichia coli (STEC) causes a wide spectrum of diseases including hemorrhagic colitis and hemolytic uremic syndrome (HUS). The current Food Safety Inspection Service (FSIS) testing methods for STEC use the Food and Drug Administration (FDA) Bacteriological Analytical Manual (BAM) protocol, which includes enrichment, cell plating, and genomic sequencing and takes time to complete, thus delaying diagnosis and treatment. We wanted to develop a rapid, sensitive, and potentially portable assay that can identify STEC by detecting Shiga toxin (Stx) using the CANARY (Cellular Analysis and Notification of Antigen Risks and Yields) B-cell based biosensor technology. Five potential biosensor cell lines were evaluated for their ability to detect Stx2. The results using the best biosensor cell line (T5) indicated that this biosensor was stable after reconstitution with assay buffer covered in foil at 4 °C for up to 10 days with an estimated limit of detection (LOD) of ≈0.1-0.2 ng/mL for days up to day 5 and ≈0.4 ng/mL on day 10. The assay detected a broad range of Stx2 subtypes, including Stx2a, Stx2b, Stx2c, Stx2d, and Stx2g but did not cross-react with closely related Stx1, abrin, or ricin. Additionally, this assay was able to detect Stx2 in culture supernatants of STEC grown in media with mitomycin C at 8 and 24 h post-inoculation. These results indicate that the STEC CANARY biosensor developed in this study is sensitive, reproducible, specific, rapid (≈3 min), and may be applicable for surveillance of the environment and food to protect public health.
Assuntos
Abrina , Toxina Shiga II , Escherichia coli , Toxina Shiga , BioensaioRESUMO
Shiga toxin-producing Escherichia coli (STEC) O145 is a major serotype associated with severe human disease. Production of Shiga toxins (Stxs), especially Stx2a, is thought to be correlated with STEC virulence. Since stx genes are located in prophages genomes, induction of prophages is required for effective Stxs production. Here, we investigated the production of Stxs in 12 environmental STEC O145:H28 strains under stresses STEC encounter in natural habitats and performed comparative analysis with two O145:H28 clinical strains, one linked to a 2010 U.S. lettuce-associated outbreak (RM13514) and the other linked to a 2007 Belgium ice cream-associated outbreak (RM13516). Similar to the outbreak strains, all environmental strains belong to Sequence Type (ST)-78 using the EcMLST typing scheme. Although all Stx1a-prophages were grouped together, variations in Stx1a production were observed prior to or following the inductions. Among all stx2a positive environmental strains, only the Stx2a-prophage in cattle isolate RM9154-C1 was clustered with the Stx2a-prophages in RM13514, the Stx2a-phage induced from a STEC O104:H4 strain linked to the 2011 outbreak of enterohemorrhagic infection in Germany, and the Stx2a-prophage in STEC O157:H7 strain EDL933, a prototype of enterohemorrhagic E. coli. Furthermore, the Stx2a-prophage in RM9154-C1 shared the same chromosomal insertion site and carried the same antiterminator Q gene and the late promoter PR' as the Stx2a-prophage in RM13514. Following mitomycin C or enrofloxacin treatment, the production of Stx2a in RM9154-C1 was the highest among all environmental strains tested. In contrast, following acid challenge and recovery, the production of Stx2a in RM9154-C1 was the lowest among all the environmental strains tested, at a level comparable to the clinical strains. A significant increase in Stx2a production was detected in all strains when exposed to H2O2, although the induction fold was much lower than those by other inducers. This low-efficiency induction of Stx-prophages by H2O2, a natural inducer of Stx-prophages, supports the hypothesis of bacterial altruism in controlling Stxs production, a strategy that assures the survival of the STEC population as a whole by sacrificing a small fraction of cells for Stxs production and release. Differential induction of Stxs among strains carrying nearly identical Stx-prophages suggests a role of host bacteria in regulating Stxs production. Our study revealed diverse Stx-prophages in STEC O145:H28 strains that were genotypically indistinguishable. Identification of a cattle isolate harboring a Stx2a-prophage associated with high virulence supports the premise that cattle, a natural reservoir of STEC, serve as a source of hypervirulent STEC strains.
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Toxina Shiga/metabolismo , Escherichia coli Shiga Toxigênica/genética , Animais , Bacteriófagos/genética , Bélgica , Bovinos , Surtos de Doenças , Escherichia coli Êntero-Hemorrágica , Microbiologia Ambiental , Infecções por Escherichia coli/microbiologia , Genoma , Genótipo , Alemanha , Humanos , Peróxido de Hidrogênio , Prófagos/genética , Sorogrupo , Toxina Shiga/genética , Toxina Shiga II/genética , VirulênciaRESUMO
Brown mushroom (Agaricus bisporus) stalk bases from mushroom waste were treated with UV-B light to rapidly increase vitamin D2 content. Chitin was also recovered from this waste and converted into chitosan by N-deacetylation. FTIR spectra showed that the mushroom chitosan were similar to chitosan from animal sources. Chitosan films were prepared using high molecular weight (HW), low molecular weight (LW) and fungal chitosan. UV-B treated mushroom particles were also incorporated into fungal chitosan films. The fungal chitosan films showed similar density, porosity and water vapor barrier properties to the LW and HW chitosan films. However, fungal chitosan films were more hydrophobic and less flexible than the LW and HW chitosan films. Addition of mushroom particles did not significantly affect mechanical or water barrier properties of the fungal chitosan films.
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Tree nuts as a group cause a significant number of fatal anaphylactic reactions to foods. Walnuts (Juglans spp.) are one of the leading causes of allergic reactions to tree nuts in the U.S. and Japan. The purpose of this study was to purify and characterize potential food allergens from black walnut. Here, we report the isolation of the black walnuts allergen Jug n 4 (an 11S globulin) by ammonium sulfate precipitation, hydrophobic interaction, and size exclusion chromatography. Reducing SDS-PAGE analysis indicated that purified Jug n 4 consists of three major bands. N-Terminal sequencing data of these bands indicated that they were the results of a post-transcriptional protease cleavage of the mature protein at a site that consists of a known conserved protease recognition motif, NGXEET. Western blot experiments revealed that 32% of the sera from 25 patients with double-blind, placebo-controlled clinical walnut allergy contained IgE antibodies that recognized Jug n 4, indicating that it is a walnut allergen. Identifying this and additional allergens may facilitate the understanding of the allergenicity of seed storage proteins in tree nuts and their cross-reactivity.
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Alérgenos/isolamento & purificação , Antígenos de Plantas/isolamento & purificação , Juglans/química , Hipersensibilidade a Noz/imunologia , Proteínas de Plantas/isolamento & purificação , Adolescente , Alérgenos/genética , Alérgenos/imunologia , Motivos de Aminoácidos , Antígenos de Plantas/genética , Antígenos de Plantas/imunologia , Precipitação Química , Criança , Cromatografia em Gel , Dicroísmo Circular , Eletroforese em Gel de Poliacrilamida , Humanos , Soros Imunes , Juglans/imunologia , Proteínas de Plantas/genética , Proteínas de Plantas/imunologia , Processamento Pós-Transcricional do RNA , Adulto Jovem , LeguminasRESUMO
Based on dendrochronological methods, we established residual chronologies of Pinus koraiensis and Picea jezoensis, with the dominant species of broadleaved Korean pine mixed forest at low altitudes chosen as the research object, to identify the key climatic factors affecting the radial growth of the two species in Xiaoxing'anling Mountains, Northeast China. The results showed that the responses of the two species to climate factors were different, and P. koraiensis was more sensitive, and hence more suitable for dendroclimatological analysis. Response function coefficients indicated that the radial growth of P. koraiensis negatively correlated with June mean temperature of current year, while positively correlated with precipitation in June of current year. There was no significant correlation between P. jezoensis and all climate variables. Spatial correlation analysis revealed that variations in chronology of P. koraiensis contained strong regional signals, and the highest correlation occurred in the vicinity of the study area. Warming caused drought stress, which was the main factor that limited the growth of P. koraiensis, and it might have adverse effects on the Korean pine if global temperature continues to increase. The coupling effects of large-scale atmospheric-oceanic variability may affect the radial growth of P. koraiensis in Xiaoxing'anling Mountains.
Assuntos
Mudança Climática , Pinus , China , Florestas , PiceaRESUMO
The 7S vicilin and 11S legumin seed storage globulins belong to the cupin protein superfamily and are major food allergens in many foods from the "big eight" food allergen groups. Here, for the first time, pecan vicilin was found to be a food allergen. Western blot experiments revealed that 30% of 27 sera used in this study and 24% of the sera from 25 patients with double-blind, placebo controlled clinical pecan allergy contained IgE antibodies specific to pecan vicilin. This allergen consists of a low-complexity region at its N-terminal and a structured domain at the C-terminal that contains two cupin motifs and forms homotrimers. The crystal structure of recombinant pecan vicilin was determined. The refined structure gave R/Rfree values of 0.218/0.262 for all data to 2.65 Å. There were two trimeric biological units in the crystallographic asymmetric unit. Pecan vicilin is also a copper protein. These data may facilitate the understanding of the nutritional value and the allergenicity relevance of the copper binding property of seed storage proteins in tree nuts.
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Carya/imunologia , Hipersensibilidade Alimentar/imunologia , Proteínas de Armazenamento de Sementes/química , Proteínas de Armazenamento de Sementes/imunologia , Adolescente , Motivos de Aminoácidos , Carya/química , Criança , Pré-Escolar , Feminino , Hipersensibilidade Alimentar/sangue , Humanos , Imunoglobulina E/sangue , Imunoglobulina E/imunologia , Masculino , Sementes/química , Sementes/imunologia , Adulto JovemRESUMO
The aims of this study were to predict, identify and characterize pine nut allergens. Korean pine (Pinus koraiensis) vicilin was predicted to be a pine nut allergen. Recombinant Korean pine vicilin was expressed in E. coli and purified. Natural Korean pine vicilin isolated from pine nuts (which displayed multiple bands in SDS-gels due to posttranslational digestion) and its full length recombinant counterpart were used to test whether it is a food allergen. The recognition of the protein (and its fragments) by patient serum IgE was analyzed by Western blot. The study included fourteen patients diagnosed with clinical pine nut allergy. Twenty nine percent of the patient sera recognized both the natural and recombinant pine nut vicilin, indicating that Korean pine vicilin is a bona fide food allergen. The serum recognition patterns of the naturally occurring protein fragments suggested that some of linear IgE epitopes may be mapped to the fragment boundaries. The chemical and thermal stability of the recombinant protein was investigated. It underwent a thermal transition with a Tm=76.6°C. The transition was accompanied by an increase in the amplitude of the circular dichroism signal at 220nm. Urea induced unfolding of the recombinant protein had a Cm of 4.6M.
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The present study reports on the development of hybrid poly(lactic acid) (PLA) fibres loaded with highly crystalline bacterial cellulose nanowhiskers (BCNW) by the novel solution blow spinning method. Furthermore, fibres with antimicrobial properties were generated by incorporating carvacrol and THC as antimicrobial agents and the biocide effect against Listeria monocytogenes was studied. Initially, PLA blow spun fibres containing BCNW were optimized in terms of morphology and thermal properties. The addition of BCNW was seen to significantly increase the viscosity and surface tension of solutions, restricting the capacity to form fibres for concentrations greater than 30 wt.-% BCNW. 15 wt.-% BCNW was selected as the optimum nanofiller loading as it led to the most uniform fibres morphology, with BCNW homogeneously distributed along the fibres' axis. Subsequently, carvacrol and THC were incorporated into the fibres to confer them with antimicrobial properties, although the hydrophobic PLA matrix did not provide an efficient release of the antimicrobials. Thus, hydrophilic substances were added in order to trigger the antimicrobials release through water sorption mechanisms. The addition of the BCNW filler was not seen to significantly increase the antimicrobial capacity of the fibres by itself and, hence, gelatin was added to help promoting further the hydrophylicity and biocide performance of the fibres. Nevertheless, for the more hydrophilic THC, the biocide capacity of the fibres with gelatin was accentuated further by the presence of the BCNW.
Assuntos
Anti-Infecciosos/química , Ácido Láctico/química , Nanofibras/química , Nanotecnologia/métodos , Polímeros/química , Anti-Infecciosos/farmacologia , Varredura Diferencial de Calorimetria , Celulose/química , Celulose/metabolismo , Cimenos , Gluconacetobacter xylinus/química , Gluconacetobacter xylinus/metabolismo , Listeria monocytogenes/efeitos dos fármacos , Monoterpenos/química , Monoterpenos/farmacologia , Poliésteres , ViscosidadeRESUMO
Apple, grape, olive, and tomato pomaces as well as almond and walnut shells were torrefied at different temperatures and times in a muffle furnace. The fiber content and thermal stability of the raw byproducts were examined and the moisture and ash contents, elemental composition, and gross calorific values of the raw and torrefied samples were characterized. Response surface methodology and a central composite design were used to examine the effects of temperature and time on mass and energy yields of the torrefied byproducts. Raw apple pomace had the highest hemicellulose content, whereas raw grape pomace had the highest lignin content. Raw tomato pomace had the highest gross calorific value because of its high carbon content. Temperature had a larger effect on mass and energy yields than time. Grape pomace generally had the highest mass and energy yields. Also, energy yields of the byproducts could be predicted from mass loss values.
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Biotecnologia/métodos , Nozes/química , Resíduos , Elementos Químicos , Temperatura , TermogravimetriaRESUMO
Biochemical characterizations of food allergens are required for understanding the allergenicity of food allergens. Such studies require a relatively large amount of highly purified allergens. The level of Pru du 4 in almond is low, and its expression in a soluble form in Escherichia coli required an expression tag. An MBP tag was used to enhance its expression and solubility. Sumo was used for the first time as a peptidase recognition site. The expression tag was removed with a sumo protease, and the resulting wild-type Pru du 4 was purified chromatographically. The stability of the allergen was investigated with chemical denaturation. The Gibbs free energy of Pru du 4 folding-unfolding transition was determined to be 5.4 ± 0.7 kcal/mol.
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Antígenos de Plantas/química , Antígenos de Plantas/isolamento & purificação , Proteínas de Plantas/química , Proteínas de Plantas/isolamento & purificação , Prunus/química , Antígenos de Plantas/genética , Antígenos de Plantas/imunologia , Clonagem Molecular , Escherichia coli/genética , Escherichia coli/metabolismo , Expressão Gênica , Proteínas de Plantas/genética , Proteínas de Plantas/imunologia , Dobramento de Proteína , Prunus/genética , Prunus/imunologiaRESUMO
Tree nuts are responsible for many cases of severe food allergies. The 7S seed storage protein vicilin has been identified as a food allergen in many kinds of tree nuts. The vicilin protein consists of an N-terminal low-complexity region with antimicrobial activity and a C-terminal domain that forms a trimeric structure that belongs to the cupin superfamily. In this study, vicilin from pecan (Carya illinoinensis) was isolated and was expressed in bacteria for the first time. The cupin structural core of the protein, residues 369-792, was purified by metal-affinity and gel-filtration chromatography to high purity. Vicilin crystals were obtained and the best crystal diffracted to 2.65â Å resolution in space group P212121.
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Carya/química , Proteínas de Armazenamento de Sementes/genética , Sequência de Bases , Cromatografia de Afinidade , Cromatografia em Gel , Cristalização , Primers do DNA , Proteínas de Armazenamento de Sementes/química , Proteínas de Armazenamento de Sementes/isolamento & purificaçãoRESUMO
UNLABELLED: Thyme essential oil (TEO) and apple skin polyphenols (ASP) are natural compounds considered as generally recognized as safe by FDA, with biological effects against bacteria and fungi. This work aimed to evaluate physical and antimicrobial properties of açaí edible films formulated with TEO and ASP at 3% and 6% (w/w) individually or combined at 3% (w/w) each. Physical properties studied include mechanical resistance, water vapor permeability (WVP), color, and thermal resistance. Antimicrobial activity against Listeria monocytogenes was determined using the overlay diffusion test. Addition of ASP resulted in improved mechanical properties. TEO at 6% (w/w) resulted in increased elongation. ASP films had significant higher WVP than control film. ASP films were lighter and had more red color than other films. Incorporation of ASP resulted in improved film thermal stability, whereas TEO caused rapid thermal decomposition. Presence of clusters was observed on the surface of films. Addition of ASP resulted in a smoother surface, whereas addition of TEO led to the formation of crater-like pits on the film surface. Açaí edible film incorporated with 6% (w/w) TEO presented the highest antimicrobial activity. However, both antimicrobials are necessary in the açaí films in order to obtain edible films with suitable physical-mechanical properties. The results of the present study showed that TEO and ASP can be used to prepare açaí edible films with adequate physical-mechanical properties and antimicrobial activity for food applications by direct contact. PRACTICAL APPLICATION: Developed açaí edible films presented antimicrobial activity against L. monocytogenes and good physical-mechanical properties, showing the potential use of açaí edible films in food preservation.
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Antibacterianos/farmacologia , Euterpe , Conservação de Alimentos/métodos , Listeria monocytogenes/efeitos dos fármacos , Óleos Voláteis/farmacologia , Extratos Vegetais/farmacologia , Polifenóis/farmacologia , Embalagem de Alimentos/métodos , Malus/química , Permeabilidade , Extratos Vegetais/química , Thymus (Planta)/químicaRESUMO
Increasing strawberry consumption has led to a growing safety concern because they are not washed after harvest. An antimicrobial edible coating could be an effective postharvest technique to ensure microbial safety and, at the same time, retain overall quality of the fruits. Response surface methodology was used to optimize the antimicrobial activity against Escherichia coli O157:H7 and Botrytis cinerea and several physical properties (turbidity, viscosity, and whitish index) of an alginate coating. A full factorial design was used to select the concentrations of carvacrol and methyl cinnamate on the basis of their effect against E. coli and B. cinerea. A central composite design was then performed to evaluate the effects/interactions of the two antimicrobials on the coating characteristics. The results from analysis of variance showed the significant fitting of all responses to the quadratic model. To attain the desirable responses, the optimal concentrations were 0.98% (w/w) carvacrol and 1.45% (w/w) methyl cinnamate.
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Alginatos/química , Anti-Infecciosos , Cinamatos/farmacologia , Embalagem de Alimentos/instrumentação , Fragaria/microbiologia , Monoterpenos/farmacologia , Botrytis/efeitos dos fármacos , Fenômenos Químicos , Cimenos , Escherichia coli O157/efeitos dos fármacos , Frutas , Ácido Glucurônico/química , Ácidos Hexurônicos/químicaRESUMO
The addition of plant essential oils to edible films and coatings has been shown to protect against bacterial pathogens and spoilage while also enhancing sensory properties of foods. This study evaluated the effect of adding 0.5 and 0.75% carvacrol (active ingredient of oregano oil) to apple- and tomato-based film-forming solutions and 0.5 and 0.75% cinnamaldehyde (active ingredient of cinnamon oil) to apple-based film-forming solutions on sensory properties of cooked chicken wrapped with these films. Paired preference tests indicated no difference between baked chicken wrapped with tomato and apple films containing 0.5% carvacrol and cinnamaldehyde compared to chicken wrapped with tomato or apple films without the plant antimicrobials. The taste panel indicated a higher preference for carvacrol-containing tomato-coated chicken over the corresponding apple coating. There was also a higher preference for cinnamaldehyde-containing apple films over corresponding carvacrol-containing wrapping. Films containing antibacterial active compounds derived from essential oils can be used to protect raw chicken pieces against bacterial contamination without adversely affecting preferences of wrapped chicken pieces after baking.
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Anti-Infecciosos , Galinhas , Embalagem de Alimentos/instrumentação , Carne , Sensação , Acroleína/administração & dosagem , Acroleína/análogos & derivados , Acroleína/química , Animais , Cimenos , Preferências Alimentares , Conservação de Alimentos/métodos , Frutas , Humanos , Solanum lycopersicum , Malus , Monoterpenos/administração & dosagem , Monoterpenos/químicaRESUMO
BACKGROUND: The effect of ultraviolet-B (UV-B) light as a postharvest treatment to enhance the antioxidant content of carrots and fresh-cut carrot products was evaluated. Four levels of UV-B dose ranging from 1.3 to 12 kJ m⻲ were applied to whole, baby and various styles of cut carrots, and the changes in antioxidant capacity, total soluble phenolics and phenylalanine ammonia-lyase (PAL, EC 4.3.1.24) activity were measured after a 3 day incubation period at 15 °C and 45% relative humidity. RESULTS: Both cutting style and dose level were factors in determining carrot responses to UV-B treatment. Antioxidant capacity increased significantly (1.4-6.6-fold). Total soluble phenolic results correlated directly with those of antioxidant capacity (R² = 0.953), indicating that the enhancements achieved were due to an increase in phenolic content. High-performance liquid chromatography analysis revealed that 5-O-caffeoylquinic acid (5-CQA) was the primary phenolic responsible for this increase. Higher PAL activity was also observed in UV-B-treated samples, indicating that the increase in 5-CQA was a biological response to UV-B exposure. CONCLUSION: UV-B treatment has the potential to increase the nutritional value of carrots and offers an exciting opportunity to increase consumer accessibility to dietary choices that are rich in antioxidants.
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Antioxidantes/análise , Daucus carota/química , Daucus carota/efeitos da radiação , Irradiação de Alimentos , Raízes de Plantas/química , Raízes de Plantas/efeitos da radiação , Raios Ultravioleta , Antioxidantes/química , Ácido Clorogênico/análogos & derivados , Ácido Clorogênico/análise , Ácido Clorogênico/química , Cromatografia Líquida de Alta Pressão , Daucus carota/enzimologia , Relação Dose-Resposta à Radiação , Manipulação de Alimentos , Embalagem de Alimentos , Fenóis/análise , Fenóis/química , Fenilalanina Amônia-Liase/metabolismo , Proteínas de Plantas/metabolismo , Raízes de Plantas/enzimologia , Ácido Quínico/análogos & derivados , Ácido Quínico/análise , Ácido Quínico/química , Solubilidade , Fatores de TempoRESUMO
Wounding stresses resulting from fresh-cut processing are known to enhance the antioxidant capacity (AC) of carrots by increasing the synthesis of phenolic compounds. Ultraviolet-B (UV-B) light exposure further promotes the formation of phenolic compounds. Changes in total soluble phenolics (TSP), 5-O-caffeoylquinic acid (5-CQA), total carotenoids, AC, and phenylalanine ammonia-lyase (PAL) activity of five commercial fresh-cut carrot products (baby carrots, carrot stixx, shredded carrots, crinkle cut coins, and oblong chips) were evaluated after exposure to UV-B dosage at 141.4 mJ/cm(2). Significant increases in TSP, AC and 5-CQA levels were observed for each sample following UV-B exposure. Increases in PAL activity were also observed in all carrot products, except crinkle cut coins. Total carotenoids of the carrot products were unchanged by UV-B exposure. Increases in AC levels corresponded directly with increases in the area/weight ratio (exposure area) of the fresh-cut carrot products.
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Antioxidantes/metabolismo , Daucus carota/metabolismo , Daucus carota/efeitos da radiação , Carotenoides/metabolismo , Daucus carota/enzimologia , Manipulação de Alimentos , Fenóis/metabolismo , Fenilalanina Amônia-Liase/metabolismo , Proteínas de Plantas/metabolismo , Raios UltravioletaRESUMO
The heat resistance of Salmonella inoculated onto almonds was determined after immersion in hot oil. Whole almonds were inoculated with Salmonella Enteritidis PT 30 or Salmonella Senftenberg 775W and heated in oil. After heating, almonds were drained, transferred to cold tryptic soy broth, and mixed with a stomacher, and samples were plated onto tryptic soy and bismuth sulfite agars. Salmonella survivor inactivation curves were upwardly concave. Rapid reductions of 2.9, 3.0, or 3.6 log CFU/g for Salmonella Enteritidis were observed after 30 s of exposure to oil at 116, 121, or 127 degrees C, respectively. Thereafter, reduction occurred at a much slower rate. Similar reductions were observed at 127 degrees C for Salmonella Senftenberg. The Weibull model was used to predict 4- and 5-log reductions of Salmonella Enteritidis after 0.74 and 1.3 min at 127 degrees C, respectively. Neither Salmonella serovar could be recovered by enrichment of 1-g samples after almonds inoculated at 5 log CFU/g were exposed to oil at 127 degrees C for 1.5 min. Standard oil roasting times and temperatures that achieve acceptable kernel color and texture should result in much greater than 5-log reductions of Salmonella in almonds.
Assuntos
Manipulação de Alimentos/métodos , Temperatura Alta , Prunus/microbiologia , Intoxicação Alimentar por Salmonella/prevenção & controle , Salmonella/crescimento & desenvolvimento , Contagem de Colônia Microbiana , Qualidade de Produtos para o Consumidor , Gorduras Insaturadas na Dieta , Contaminação de Alimentos/análise , Contaminação de Alimentos/prevenção & controle , Humanos , Salmonella enteritidis/crescimento & desenvolvimento , Fatores de TempoRESUMO
UNLABELLED: Large volumes of fine particulate matter or "dust" (soil, hulls, and shells) generated when hulls and shells are removed from almond kernels complicate cleaning and sanitation procedures in the huller-sheller (HS) environment. This study evaluated the efficacy of 3 aqueous quaternary ammonium sanitizers (AQuats) and an isopropyl alcohol-based quaternary ammonium sanitizer (IPAQuat) for reducing Salmonella in dust collected from 2 HS facilities. Dust (1 g) was thoroughly mixed with 1 to 2 mL of inoculum (1 to 5 log CFU/g) before adding 1 to 7 mL of water, an AQuat (200 or 1000 ppm), or IPAQuat (200 ppm, 58.6% isopropyl alcohol) and incubated at 15 and 30 degrees C for up to 21 d. At either 15 or 30 degrees C increases in Salmonella populations in the dust were not significantly different following addition of either water or AQuats. No significant differences were observed upon water or AQuat addition, either among the 3 AQuats tested, the concentration or volume of AQuat, or the initial level of Salmonella. When IPAQuat was added to dust inoculated at 1 to 7 log CFU/g, Salmonella levels were reduced to less than 1.3 log CFU/g after treatment and after incubation at 30 degrees C for 48 h. IPAQuat was an effective sanitizer compared to the AQuats, even in the presence of high levels of organic material. Recent large-scale outbreaks of salmonellosis with low-moisture foods have increased concerns regarding their safety. Little research or guidance is available on appropriate cleaning and sanitation programs for these food types. This research is focused on an evaluation of sanitation options for low-moisture foods, in particular almonds. The information should be applicable and useful to the nut industry and to other low-moisture foods. PRACTICAL APPLICATION: Recent large-scale outbreaks of salmonellosis with low-moisture foods have increased concerns regarding their safety. Little research or guidance is available on appropriate cleaning and sanitation programs for these food types. This research is focused on an evaluation of sanitation options for low-moisture foods, in particular almonds. The information should be applicable and useful to the nut industry and to other low-moisture foods.