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1.
Appl Opt ; 60(7): 1924-1929, 2021 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-33690282

RESUMEN

A rapid and label free aflatoxin B1 (AFB1) microfluid sensor was proposed and tested. The device was fabricated with hollow-core photonics crystal fiber infiltrated with the AFB1 solution. The autofluorescence emitting from the AFB1 molecules was detected. The sensor length was optimized. The AFB1 concentration was tested with a 4 cm long sensor. The best limit of detection was achieved as low as 1.34 ng/ml, which meets the test requirement of the national standards for AFB1 in food. The effectiveness of this sensor being applied in beer solution was also verified to be a little more sensitive than in aqueous solution. Compared with traditional AFB1 detection methods, the proposed single-ended device perfectly satisfies the demand of process control in alcoholic beverages manufacture.


Asunto(s)
Aflatoxina B1/química , Bebidas Alcohólicas/análisis , Contaminación de Alimentos/análisis , Dispositivos Laboratorio en un Chip , Bebidas Alcohólicas/microbiología , Microbiología de Alimentos , Límite de Detección
2.
Int J Food Microbiol ; 344: 109114, 2021 Apr 16.
Artículo en Inglés | MEDLINE | ID: mdl-33652336

RESUMEN

Thermal inactivation kinetics of Salmonella in low moisture foods are necessary for developing proper thermal processing parameters for pasteurization. The effect of water activity on thermal inactivation kinetics of Salmonella and Enterococcus faecium NRRL B-2354 in ground black pepper has not been studied previously. Identification of a suitable surrogate assists in conducting in-plant process validations. Ground black pepper was inoculated with a 5-serotype Salmonella cocktail or E. faecium NRRL B-2354, equilibrated to water activities of 0.25, 0.45 or 0.65 in a humidity-controlled chamber, and isothermally treated at different temperatures. The survivor data were used for fitting the log-linear models to obtain the D and z-values of Salmonella and E. faecium in ground black pepper. Modified Bigelow models were developed to evaluate the effects of temperature and water activity on the thermal inactivation kinetics of Salmonella and E. faecium. Water activity and temperature showed significant negative effects on the thermal resistance of Salmonella and E. faecium in ground black pepper. For example, significantly higher D values of Salmonella were observed at water activity of 0.45 (D70°C = 20.5 min and D75°C = 7.8 min) compared to water activity of 0.65 (D70°C = 3.9 min and D75°C = 2.0 min). D-values of E. faecium were significantly higher than those of Salmonella at all three water activities, indicating that E. faecium is a suitable surrogate for Salmonella in thermal processing validation.


Asunto(s)
Enterococcus faecium/crecimiento & desarrollo , Pasteurización/métodos , Piper nigrum/microbiología , Salmonella/crecimiento & desarrollo , Recuento de Colonia Microbiana , Enterococcus faecium/clasificación , Enterococcus faecium/fisiología , Microbiología de Alimentos , Calor , Salmonella/fisiología , Agua/análisis
3.
Int J Food Microbiol ; 344: 109110, 2021 Apr 16.
Artículo en Inglés | MEDLINE | ID: mdl-33657496

RESUMEN

Salmonella genus has foodborne pathogen species commonly involved in many outbreaks related to the consumption of chicken meat. Many studies have aimed to model bacterial inactivation as a function of the temperature. Due to the large heterogeneity of the results, a unified description of Salmonella spp. inactivation behavior is hard to establish. In the current study, by evaluating the root mean square errors, mean absolute deviation, and Akaike and Bayesian information criteria, the double Weibull model was considered the most accurate primary model to fit 61 datasets of Salmonella inactivation in chicken meat. Results can be interpreted as if the bacterial population is divided into two subpopulations consisting of one more resistant (2.3% of the total population) and one more sensitive to thermal stress (97.7% of the total population). The thermal sensitivity of the bacteria depends on the fat content of the chicken meat. From an adapted version of the Bigelow secondary model including both temperature and fat content, 90% of the Salmonella population can be inactivated after heating at 60 °C of chicken breast, thigh muscles, wings, and skin during approximately 2.5, 5.0, 9.5, and 57.4 min, respectively. The resulting model was applied to four different non-isothermal temperature profiles regarding Salmonella growth in chicken meat. Model performance for the non-isothermal profiles was evaluated by the acceptable prediction zone concept. Results showed that >80% of the predictions fell in the acceptable prediction zone when the temperature changes smoothly at temperature rates lower than 20 °C/min. Results obtained can be used in risk assessment models regarding contamination with Salmonella spp. in chicken parts with different fat contents.


Asunto(s)
Pollos/microbiología , Calor , Carne/microbiología , Intoxicación Alimentaria por Salmonella/prevención & control , Salmonella/crecimiento & desarrollo , Animales , Teorema de Bayes , Recuento de Colonia Microbiana , Microbiología de Alimentos , Salmonella/clasificación
4.
Int J Food Microbiol ; 344: 109108, 2021 Apr 16.
Artículo en Inglés | MEDLINE | ID: mdl-33667851

RESUMEN

The study determined the growth kinetic parameters of a cocktail of Listeria monocytogenes 1/2c and 4b strains in coconut water (pH 4.76, 5.0°Brix, 0.09% malic acid, aw 0.998) subjected to low (~2.0 log CFU/mL) and high (~4.0 log CFU/mL) contamination levels, and exposed to different storage temperatures (4 °C, 17 °C, 30 °C, and 35 °C). The pathogen proliferated in all tested conditions except in that with low contamination stored at 4 °C. Despite not growing at 4 °C, the pathogen was detectable throughout the storage period, which lasted for almost 400 h. In conditions where the pathogens proliferated, growth lag (tlag) ranged from 0.0 to 68.3 h. The growth rates (KG) ranged from 0.05 to 0.48 log CFU/h, while the final populations ranged from 6.3 to 8.7 log CFU/mL. Both storage temperature and contamination level significantly (P < 0.05) affected the growth parameters. Sanitary risk times (SRT) were determined with the microbiological shelf life (SL) of coconut water. In some of the conditions tested, SRT took place before SL (SRT < SL), emphasizing the importance of having good hygienic and manufacturing practices in place for such a vulnerable commodity.


Asunto(s)
Cocos/microbiología , Conservación de Alimentos , Almacenamiento de Alimentos , Listeria monocytogenes/crecimiento & desarrollo , Frío , Recuento de Colonia Microbiana , Manipulación de Alimentos , Microbiología de Alimentos , Calor
5.
Int J Food Microbiol ; 344: 109116, 2021 Apr 16.
Artículo en Inglés | MEDLINE | ID: mdl-33676332

RESUMEN

Staphylococcus aureus is among the most common zoonotic pathogens originating from animals consumed as food, especially raw chicken meat (RCM). As far as we know, this might be the first report that explores the efficacy of metal oxide nanoparticles (MONPs), such as zinc peroxide nanoparticles (ZnO2-NPs), zinc oxide nanoparticles (ZnO-NPs), and titanium dioxide nanoparticles (TiO2-NPs) against multidrug resistant (MDR) and/or pandrug resistant (PDR) S. aureus strains with a strong biofilm-producing ability isolated from RCM and giblets. The overall prevalence of coagulase-positive staphylococci was 21%, with a contamination level range between 102 and 104 CFU/g. The incidence of virulence genes See (21/36), pvl (16/36), clfA (15/36), sec (12/36), tst (12/36), and sea (11/36) among S. aureus strains were relatively higher those of seb, sed, fnbA, and fnbB. For antimicrobial resistance gene distribution, most strains harbored the blaZ gene (25/36), aacA-aphD gene (24/36), mecA gene (22/36), vanA gene (20/36), and apmA gene (20/36) confirmed the prevalence of MDR among S. aureus of RCM products. However, cfr (11/36), spc (9/36), and aadE (7/36) showed a relatively lower existence. The data of antibiogram resistance profiles was noticeably heterogeneous (25 patterns) with 32 MDR and four PDR S. aureus strains. All tested strains had a very high MAR index value (>0.2) except the P11 pattern (GEN, MXF, PMB), which showed a MAR index of 0.19. Among the strong biofilm-producing ability (BPA), 14 (70%) strains were isolated from wet markets, while only six strong BPA strains were isolated from supermarkets. The mean values of BPA ranged from 2.613 ± 0.04 to 11.013 ± 0.05. Clearly, ZnO2-NPs show significant inhibitory activity against S. aureus strains compared with those produced by the action of ZnO-NPs and TiO2-NPs. The results of anti-inflammatory activity suggest ZnO2-NPs as a lead compound for designing an alternative antimicrobial agent against drug-resistant and strong biofilm-producing S. aureus isolates from retail RCM and giblets.


Asunto(s)
Antibacterianos/farmacología , Contaminación de Alimentos/prevención & control , Staphylococcus aureus/crecimiento & desarrollo , Titanio/farmacología , Óxido de Zinc/farmacología , Animales , Biopelículas/efectos de los fármacos , Biopelículas/crecimiento & desarrollo , Pollos/microbiología , Farmacorresistencia Bacteriana Múltiple/genética , Contaminación de Alimentos/análisis , Microbiología de Alimentos , Carne/microbiología , Nanopartículas del Metal , Pruebas de Sensibilidad Microbiana , Infecciones Estafilocócicas/epidemiología , Infecciones Estafilocócicas/prevención & control , Staphylococcus aureus/efectos de los fármacos , Staphylococcus aureus/aislamiento & purificación , Virulencia/genética
6.
Nutr. hosp ; 38(1): 146-151, ene.-feb. 2021. tab, graf
Artículo en Español | IBECS | ID: ibc-198851

RESUMEN

ANTECEDENTES Y OBJETIVO: las aflatoxinas son metabolitos secundarios producidos por hongos de los géneros Aspergillus y Penicillium. Estos hongos contaminan los cereales y varios otros tipos de alimentos. Los efectos fisiopatológicos de las aflatoxinas en los seres humanos incluyen el cáncer de hígado, la cirrosis y la acumulación en los tejidos humanos. El objetivo del estudio fue cuantificar las aflatoxinas cancerígenas en alimentos no procesados vendidos en los mercados de alimentos de 13 distritos de la ciudad de Lima, Perú, y discutir el efecto sobre la salud pública. MATERIALES Y MÉTODOS: se realizó un ensayo inmunoenzimático -utilizando el kit Veratox(R) para la aflatoxina total- a fin de detectar aflatoxinas en los alimentos de consumo humano, mencionándose además la implicación de los hallazgos para la salud pública. RESULTADOS: los alimentos más contaminados que se encontraron fueron el cacahuete o maní (Arachis hypogaea) (149,7 ppb) del mercado Limoncillo del distrito de Rímac y el ají panca o chile rojo peruano (Capsicum chinense) (56,4 ppb) del mercado central del distrito de Comas. El cacahuete se puede consumir crudo en pastas o cremas y el ají panca también se consume a veces crudo, siempre de forma sostenida en el tiempo al formar parte de la gastronomía típica de Perú. CONCLUSIONES: se demuestra un alto riesgo para la salud pública debido al vínculo entre las aflatoxinas de estos alimentos y el cáncer de hígado, principalmente, en una ciudad donde el cáncer hepático y el gástrico son prevalentes


INTRODUCTION AND OBJECTIVES: aflatoxins are secondary metabolites produced by fungi of the Aspergillus and Penicillium geni. These fungi contaminate cereals and several other types of food. The pathophysiologic effects of aflatoxins in humans include liver cancer, cirrhosis, and accumulation in human tissues. The study aimed to quantify carcinogenic aflatoxins in unprocessed food sold in the foodstuff markets of 13 districts of the city of Lima, Perú, and to discuss their effects for public health. METHODS: in order to so, we performed an immunoenzymatic assay using a Veratox(R) kit for total aflatoxin to detect aflatoxins in food for human consumption, and the implications of our findings for public health. RESULTS: the most contaminated foods we found included peanuts (Arachis hypogaea) (149.7 ppb) from the Limoncillo market at the Rimac district, and "ají panca" or Peruvian red chili pepper (Capsicum chinense) (56.4 ppb) from the central market at the Comas district. Peanuts may be eaten raw in pasta or creams, and Capsicum chinense is also eaten sometimes raw, always in a sustained manner over time as part of typical Peruvian cuisine. CONCLUSIONS: we demonstrated a high risk to public health due to the link between aflatoxins in these foods and mainly liver cancer, in a city where the hepatic cancer and gastric cancer are prevalent


Asunto(s)
Humanos , Aflatoxinas/efectos adversos , Aflatoxinas/análisis , Consumo de Alimentos/normas , Microbiología de Alimentos , Perú , Arachis , Capsicum , Neoplasias Hepáticas/epidemiología , Neoplasias Hepáticas/etiología , Neoplasias Gástricas/epidemiología , Estudios Transversales , Estudios Prospectivos
7.
Methods Mol Biol ; 2246: 279-290, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33576996

RESUMEN

Foodborne diseases are a major global public health concern. The gold standard detection techniques, namely culture plating techniques, are nowadays considered inadequate for the modern food industry mainly due to the time requirements of this sector. As such, the adoption of faster detection methods to be routinely used in screening the protocols of foodborne pathogens is required. Fluorescence in situ Hybridization (FISH) methods have been described as a valid alternative to standard plating techniques and are compatible with the requirements of the food industry.Here, we give an overview of the methodological aspects to consider regarding sample preparation and sample analysis for pathogen detection in food matrices by FISH methodologies.


Asunto(s)
Microbiología de Alimentos/métodos , Hibridación Fluorescente in Situ/métodos , Técnicas Biosensibles/métodos , Contaminación de Alimentos/prevención & control , Industria de Alimentos/métodos
8.
Washington, D.C.; OPS; 2021-02-19.
en Español | PAHO-IRIS | ID: phr-53292

RESUMEN

La evaluación de riesgos caracteriza la exposición humana a un peligro y estima la probabilidad de que se produzcan efetos adversos para la salud. Puede utilizarse para examinar el efecto adverso de sustancias añadidas de manera deliberada a los alimentos (por ejemplo, aditivos alimentarios, productos químicos agrícolas o veterinarios) y sustancias que se encuentran de forma inadvertida en los alimentos (por ejemplo, contaminantes ambientales, toxinas naturales o microorganismos patógenos), así como el impacto de las nuevas tecnologías. La evaluación de riesgos es uno de los componentes principales del análisis de riesgos, en el que deben basarse las políticas de inocuidad alimentaria: evaluación de riesgos (asesoramiento científico y análisis de datos), gestión del riesgo (reglamentación y control) y comunicación del riesgo. Las decisiones relativas a la gestión del riesgo dependen de los resultados de las evaluaciones de riesgo, aunque también pueden considerar la importancia del riesgo para salud pública y los costos técnicos, económicos y sociales. Este manual abarca las definiciones y principios del análisis de riesgos; los pasos que se han de seguir para incorporarlo en las políticas públicas; los fundamentos, las etapas y la información necesaria para una evaluación de riesgos microbiológicos; y la metodología para realizar una evaluación cuantitativa de riesgos. Por último, incluye varios ejemplos y las principales herramientas y programas en línea para construir un modelo cuantitativo de riesgos. Está dirigido a profesionales de la alimentación con conocimientos básicos en microbiología y evaluación de riesgos, evaluadores de riesgos, gestores de riesgos, epidemiólogos, legisladores, científicos y responsables de la toma de decisiones.


Asunto(s)
Fiebre Aftosa , Farmacorresistencia Microbiana , Enfermedades Transmisibles , Toxicología , Inocuidad de los Alimentos , Microbiología de Alimentos , Alimentos , Enfermedades Transmitidas por los Alimentos , Factores de Riesgo
9.
Curr Top Microbiol Immunol ; 431: 79-102, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33620649

RESUMEN

Numerous studies point out that at present, a complete elimination of Campylobacter species in the poultry food chain is not feasible. Thus, the current aim should be to establish control measures and intervention strategies to minimize the occurrence of Campylobacter spp. in livestock (esp. poultry flocks) and to reduce the quantitative Campylobacter burden along the food chain in animals and subsequently in foods. The most effective measures to mitigate Campylobacter focus on the primary production stage. Nevertheless, measures applied during slaughter and processing complement the general meat hygiene approaches by reducing fecal contamination during slaughtering and processing and as a consequence help to reduce Campylobacter in poultry meat. Such intervention measures at slaughter and processing level would include general hygienic improvements, technological innovations and/or decontamination measures that are applied at single slaughter or processing steps. In particular, approaches that do not focus on a single intervention measure would need to be based on a thorough process of evaluation, and potential combinatory effects have to be modeled and tested. Finally, the education of all stakeholders (including retailers, food handlers and consumers) is required and will help to increase awareness for the presence of foodborne pathogens in raw meat and meat products and can thus aid in the development of the required good kitchen hygiene.


Asunto(s)
Infecciones por Campylobacter , Animales , Infecciones por Campylobacter/prevención & control , Infecciones por Campylobacter/veterinaria , Cadena Alimentaria , Manipulación de Alimentos , Microbiología de Alimentos , Aves de Corral
10.
Waste Manag ; 124: 102-109, 2021 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-33611154

RESUMEN

The 2011-2016 reports from the Food and Agriculture Organization of the United Nations has stated that annual food loss and waste occurs on a massive scale in fisheries and aquaculture. This study aimed to explore advanced technologies to recycle wasted salmon as an industrial resource with high commercial value by applying enzymatic hydrolysis under HPCD. Our results showed that HPCD treatment at 50 °C and 1 MPa for 16 h effectively prevents salmon from microbial contamination. Real-time PCR analysis demonstrated that HPCD was also able to inhibit an increase in bacteria at moderate temperatures. Based on NGS analysis, there was a very low abundance of Bacillus and some histamine producers, such as Pseudomonas, Acinetobacter, Enterobacter, and Klebsiella, detected in samples treated using HPCD at 50 °C and 1 MPa for 16 h. Hydrolysate analysis showed that HPCD treatment at 1 MPa did not affect the hydrolysates from salmon. It is anticipated that the results from this study will support the application of HPCD in industrial enzymatic hydrolysis and increase the sustainability of bio-based materials.


Asunto(s)
Dióxido de Carbono , Microbiología de Alimentos , Animales , Descontaminación , Carne , Salmón
11.
Int J Food Microbiol ; 342: 109056, 2021 Mar 16.
Artículo en Inglés | MEDLINE | ID: mdl-33540190

RESUMEN

The interest in the consumption of African indigenous leafy vegetables increased in African countries, e.g. Kenya, within the last years. One example of African indigenous leafy vegetables is African nightshade (Solanum scabrum) which is nutritious, rich in proteins and micronutrients and therefore could contribute to a healthy diet. African nightshade has several agricultural advantages. However, the most important disadvantage is the fast perishability which leads to enormous post-harvest losses. In this study, we investigated the fermentation of African nightshade as a post-harvest processing method to reduce post-harvest losses. The two lactic acid bacterial starter strains Lactiplantibacillus plantarum BFE 5092 and Limosilactobacillus fermentum BFE 6620 were used to inoculate fermentations of African nightshade leaves with initial counts of 106-107 cfu/ml. Uninoculated controls were conducted for each fermentation trial. Fermentations were performed both in Kenya and in Germany. The success of the inoculated starter cultures was proven by the measurement of pH values and determination of lactic acid concentration. Lactobacilli strains dominated the microbiota of the starter inoculated samples in contrast to the non-inoculated controls. This was supported by classical culture-dependent plating on different microbiological media as well as by the culture-independent molecular biological methods denaturing gradient gel electrophoresis and 16S rRNA gene high-throughput amplicon sequencing. We could demonstrate that the use of the selected starter cultures for fermentation of African nightshade leaves led to controlled and reliable fermentations with quick acidification. Thus, controlled fermentation with appropriate starter cultures is a promising method for post-harvest treatment of African nightshade leaves.


Asunto(s)
Alimentos y Bebidas Fermentados/microbiología , Lactobacillales/metabolismo , Solanum , Verduras/microbiología , África , Fermentación , Microbiología de Alimentos , Ácido Láctico/análisis , Ácido Láctico/metabolismo , Lactobacillus/metabolismo , Microbiota , Hojas de la Planta/microbiología , ARN Ribosómico 16S/genética
12.
Int J Food Microbiol ; 342: 109075, 2021 Mar 16.
Artículo en Inglés | MEDLINE | ID: mdl-33550153

RESUMEN

In many countries campylobacteriosis ranks as one of the most frequently reported foodborne illnesses and poultry is the commodity that is most often associated with these illnesses. Nevertheless, efforts to reduce the occurrence of pathogen contamination on poultry are often more focused on Salmonella. While some control measures are pathogen specific, such as pre-harvest vaccination for Salmonella, improvements in sanitary dressing and interventions applied during the slaughter process can be effective against all forms of microbial contamination. To investigate the potential effectiveness of these non-specific pathogen reduction strategies in the United States, it is helpful to assess if, and by how much, Campylobacter contamination of chicken meat has changed across time. This study assesses change considering data collected in both slaughter and retail establishments and comparing observed trends in contamination with trends in human surveillance data. The results support the assertion that substantial reductions in Campylobacter contamination of chicken meat in the late 1990s and early 2000s contributed to a reduction in the human case rate of campylobacteriosis. Further reductions in chicken meat contamination between 2013 and 2018 are more difficult to associate with trends in human illnesses, with one contributing factor being the inclusion of culture independent diagnostic test results in the official case counts during that time. Other contributing factors are discussed.


Asunto(s)
Infecciones por Campylobacter/epidemiología , Campylobacter/aislamiento & purificación , Contaminación de Alimentos/estadística & datos numéricos , Enfermedades Transmitidas por los Alimentos/epidemiología , Productos Avícolas/microbiología , Animales , Infecciones por Campylobacter/prevención & control , Pollos , Contaminación de Alimentos/prevención & control , Microbiología de Alimentos , Enfermedades Transmitidas por los Alimentos/microbiología , Enfermedades Transmitidas por los Alimentos/prevención & control , Humanos , Estados Unidos/epidemiología
13.
Int J Food Microbiol ; 342: 109092, 2021 Mar 16.
Artículo en Inglés | MEDLINE | ID: mdl-33607541

RESUMEN

Tomato is widely consumed and marketed as juice, puree, or fresh product. Nevertheless, 30% of its harvest volume is lost because of the fungus Alternaria alternata. This research aimed to provide early detection methods for this fungal decay on tomato juice and fresh fruit. Biomass content, CO2, O2 and volatile compounds (VOCs) during A. alternata growth in tomato juice and fruit at two ripening stages (breaker and red colour) were evaluated. Additionally, CO2 and VOCs data set were analysed with a hierarchical cluster technique (HCA) to explore the differences between inoculated and non-inoculated samples. Biomass was determined by gravimetry, CO2 and O2 by gas chromatography (GC), and VOCs by GC-mass spectrometry. Biomass content was not drastically modified by tomato's ripening stage (3-6 mg of dry weight). CO2 in tomato juice was considerably higher in the inoculated samples with A. alternata (27-63%) than in the non-inoculated ones (2.8-6.6%), regardless of the ripeness stage; while in tomato fruit CO2 was higher at breaker stage and inoculated with A. alternata (33-41%) than the remaining treatments (9-23%). It was also observed that, except for limonene, trans-sabinene hydrate, and rhodovibrin, VOCs' release during the interaction between tomato juice and A. alternata was different from the fresh tomato and A. alternata interaction. Only the HCA based on CO2 data showed clear differences between the inoculated and non-inoculated tomato juice and fruit at both ripening stages.


Asunto(s)
Alternaria/aislamiento & purificación , Jugos de Frutas y Vegetales/microbiología , Frutas/microbiología , Lycopersicon esculentum/microbiología , Alternaria/metabolismo , Biomasa , Dióxido de Carbono/análisis , Dióxido de Carbono/metabolismo , Microbiología de Alimentos , Frutas/química , Jugos de Frutas y Vegetales/análisis , Compuestos Orgánicos Volátiles/análisis , Compuestos Orgánicos Volátiles/metabolismo
14.
Nat Med ; 27(2): 321-332, 2021 02.
Artículo en Inglés | MEDLINE | ID: mdl-33432175

RESUMEN

The gut microbiome is shaped by diet and influences host metabolism; however, these links are complex and can be unique to each individual. We performed deep metagenomic sequencing of 1,203 gut microbiomes from 1,098 individuals enrolled in the Personalised Responses to Dietary Composition Trial (PREDICT 1) study, whose detailed long-term diet information, as well as hundreds of fasting and same-meal postprandial cardiometabolic blood marker measurements were available. We found many significant associations between microbes and specific nutrients, foods, food groups and general dietary indices, which were driven especially by the presence and diversity of healthy and plant-based foods. Microbial biomarkers of obesity were reproducible across external publicly available cohorts and in agreement with circulating blood metabolites that are indicators of cardiovascular disease risk. While some microbes, such as Prevotella copri and Blastocystis spp., were indicators of favorable postprandial glucose metabolism, overall microbiome composition was predictive for a large panel of cardiometabolic blood markers including fasting and postprandial glycemic, lipemic and inflammatory indices. The panel of intestinal species associated with healthy dietary habits overlapped with those associated with favorable cardiometabolic and postprandial markers, indicating that our large-scale resource can potentially stratify the gut microbiome into generalizable health levels in individuals without clinically manifest disease.


Asunto(s)
Microbioma Gastrointestinal/genética , Metagenoma/genética , Microbiota/genética , Obesidad/microbiología , Adulto , Biomarcadores/metabolismo , Blastocystis/genética , Glucemia/metabolismo , Niño , Dieta/efectos adversos , Ayuno/metabolismo , Conducta Alimentaria , Femenino , Microbiología de Alimentos , Glucosa/genética , Secuenciación de Nucleótidos de Alto Rendimiento , Humanos , Masculino , Persona de Mediana Edad , Obesidad/genética , Obesidad/metabolismo , Periodo Posprandial/genética , Prevotella/genética , Prevotella/aislamiento & purificación
15.
Appl Environ Microbiol ; 87(6)2021 02 26.
Artículo en Inglés | MEDLINE | ID: mdl-33397695

RESUMEN

Inoculation studies are important when assessing microbial survival and growth in food products. These studies typically involve the pregrowth of multiple strains of a target pathogen under a single condition; this emphasizes strain diversity. To gain a better understanding of the impacts of strain diversity ("nature") and pregrowth conditions ("nurture") on subsequent bacterial growth in foods, we assessed the growth and survival of Salmonella enterica (n = 5), Escherichia coli (n = 6), and Listeria (n = 5) inoculated onto tomatoes, precut lettuce, and cantaloupe rind, respectively. Pregrowth conditions included (i) 37°C to stationary phase (baseline), (ii) low pH, (iii) high salt, (iv) reduced water activity, (v) log phase, (vi) minimal medium, and (vii) 21°C. Inoculated tomatoes were incubated at 21°C; lettuce and cantaloupe were incubated at 7°C. Bacterial counts were assessed over three phases, including initial reduction (phase 1), change in bacterial numbers over the first 24 h of incubation (phase 2), and change over the 7-day incubation (phase 3). E. coli showed overall decline in counts (<1 log) over the 7-day period, except for a <1-log increase after pregrowth in high salt and to mid-log phase. In contrast, S. enterica and Listeria showed regrowth after an initial reduction. Pregrowth conditions had a substantial and significant effect on all three phases of S. enterica and E. coli population dynamics on inoculated produce, whereas strain did not show a significant effect. For Listeria, both pregrowth conditions and strain affected changes in phase 2 but not phases 1 and 3.IMPORTANCE Our findings suggest that inclusion of multiple pregrowth conditions in inoculation studies can best capture the range of growth and survival patterns expected for Salmonella enterica and Escherichia coli present on produce. This is particularly important for fresh and fresh-cut produce, where stress conditions encountered by pathogens prior to contamination can vary widely, making selection of a typical pregrowth condition virtually impossible. Pathogen growth and survival data generated using multiple pregrowth conditions will allow for more robust microbial risk assessments that account more accurately for uncertainty.


Asunto(s)
Cucumis melo/microbiología , Escherichia coli/crecimiento & desarrollo , Lechuga/microbiología , Listeria/crecimiento & desarrollo , Lycopersicon esculentum/microbiología , Salmonella enterica/crecimiento & desarrollo , Recuento de Colonia Microbiana , Microbiología de Alimentos
16.
Artículo en Inglés | MEDLINE | ID: mdl-33435627

RESUMEN

The prevalence of bacteria with multidrug-resistance (MDR) is a significant threat to public health globally. Listeria spp. are naturally ubiquitous, with L. monocytogenes particularly being ranked as important foodborne disease-causing microorganisms. This study aimed to evaluate the incidence and determine the antimicrobial resistance (AMR) profiles of multidrug-resistant Listeria spp. (MDRL) isolated from different environmental samples (river and irrigation water) in the Sarah Baartman District Municipality (SBDM), Eastern Cape Province (ECP), South Africa. Molecular identification and characterization were carried out using polymerase chain reaction (PCR) and isolates that exhibited phenotypic resistance were further screened for relevant antimicrobial-resistant genes (ARGs). Findings revealed a total of 124 presumptive Listeria isolates; 69 were molecularly confirmed Listeria species. Out of the confirmed species, 41 isolates (59%) were classified as L. monocytogenes while 9 (13%) were classified as L. welshimeri. All Listeria spp. exhibited phenotypic resistance against ampicillin, penicillin, and trimethoprim-sulphamethoxazole and further screening revealed ARGs in the following proportions: sulI (71%), blaTEM (66%), tetA (63%), and blaCIT (33%). Results confirmed the occurrence of ARGs among Listeria inhabiting surface waters of ECP. The present study indicates that the river water samples collected from SBDM are highly contaminated with MDRL, hence, constituting a potential health risk.


Asunto(s)
Listeria monocytogenes , Listeria , Antibacterianos/farmacología , Farmacorresistencia Bacteriana , Microbiología de Alimentos , Listeria/genética , Listeria monocytogenes/genética , Pruebas de Sensibilidad Microbiana , Reacción en Cadena de la Polimerasa , Sudáfrica/epidemiología
17.
Artículo en Inglés | MEDLINE | ID: mdl-33480838

RESUMEN

During a project focusing on the diversity of meat microbiota associated with beef ripening, a Pseudomonas strain was isolated exhibiting high 16S rRNA gene sequence similarities (>99 %) to Pseudomonas carnis DSM 107652T, P. lactis DSM 29167T, P. paralactis DSM 29164T and P. azotoformans DSM 18862T. Phylogenetic analysis of the complete rpoB gene sequences of the isolate V5/DAB/2/5T indicated a separate branch with about 99.0 % nucleotide identities to the closest relatives P. carnis DSM 107652T, P. lactis DSM 29167T and P. paralactis DSM 29164T, while average nucleotide identities (ANIb) calculated from the draft genomes were 94.8, 94.2 and 90.2 %, respectively. Pairwise genome-to-genome distance calculations (GGDC) resulted in values of 67.7, 63.5 and 45.7 %, respectively, lying below the actual species demarcation line as well. A second isolate, UBT403, was detected some years later by using matrix-assisted laser desorption ionization-time of flight MS of the microbiota of minced beef. The fatty acid profile of V5/DAB/2/5T consisted of C16 : 0, summed feature C 16 : 1 ω7c/iso-C15 : 0 2-OH, C18 : 1 ω7c, C17 : 0 cyclo, C12 : 0, C12 : 0 3-OH, C10 : 0 3-OH and C12 : 0 2-OH. The major cellular lipids were aminopholipids, phospholipids, phosphatidylethanolamine and phosphatidylglycerol; the major quinone was Q9 with a minor proportion of Q8. Based on phenotypic and chemotaxonomic characterizations, the isolates can be considered as representing a novel species, for which the name Pseudomonas paracarnis sp. nov. is proposed. The type strain is V5/DAB/2/5T (=DSM 111363T=LMG 31846T); a second strain is UBT403 (=DSM 111362=LMG 31847).


Asunto(s)
Microbiología de Alimentos , Filogenia , Pseudomonas/clasificación , Carne Roja/microbiología , Animales , Técnicas de Tipificación Bacteriana , Composición de Base , Bovinos , ADN Bacteriano/genética , Ácidos Grasos/química , Hibridación de Ácido Nucleico , Fosfolípidos/química , Pseudomonas/aislamiento & purificación , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADN , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción , Vitamina K 2/análogos & derivados , Vitamina K 2/química
18.
Food Chem ; 347: 129069, 2021 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-33493839

RESUMEN

The growth and metabolism of Alicyclobacillus acidoterrestris can lead to the spoilage of commercial fruit juice. Existing methods have some drawbacks such as complex sample pretreatment, skilled technician requirement, reduced sensitivity and specificity. Herein, a novel fluorescence immunoassay was developed using a monoclonal antibody (mAb) against A. acidoterrestris as the sensing element and carbon dots (CDs) as the signal response unit. The CDs can be quenched via fluorescence resonance energy transfer (FRET) by the oxidization product of p-phenylenediamine (PPD), a chromogenic substrate of horseradish peroxidase (HRP). This approach showed enhanced accuracy and sensitivity with relatively low limit of detection (LOD) of 6.16 × 102 CFU mL-1. Moreover, apple juice contaminated with 1 CFU mL-1 of A. acidoterrestris can be identified after 24 h enrichment. This fluorescence immunoassay could serve as a powerful tool for laboratory identification and on-site inspection of A. acidoterrestris, reducing the adverse effect on the quality of fruit juice.


Asunto(s)
Alicyclobacillus/aislamiento & purificación , Anticuerpos Monoclonales/inmunología , Jugos de Frutas y Vegetales/microbiología , Inmunoensayo/métodos , Malus/microbiología , Puntos Cuánticos/química , Alicyclobacillus/inmunología , Anticuerpos Monoclonales/química , Carbono/química , Transferencia Resonante de Energía de Fluorescencia , Microbiología de Alimentos , Límite de Detección , Malus/metabolismo
19.
Int J Food Microbiol ; 341: 109050, 2021 Mar 02.
Artículo en Inglés | MEDLINE | ID: mdl-33498008

RESUMEN

Dromedary camel milk is generally considered a valuable and marketable commodity but its production suffers from poor hygienic conditions that result in low microbiological quality and the presence of various pathogens. The objective of the present study was to provide a detailed report of the bacterial species level composition of Moroccan raw camel milk samples that can serve as a starting point for the selection of starter cultures to facilitate a change in manufacturing practices to an improved and safer production system. The composition of the bacterial community in four freshly collected raw camel milk samples was analyzed by performing a large-scale isolation campaign combined with 16S rRNA gene amplicon sequencing. A total of 806 isolates were obtained from four raw camel milk samples using ten combinations of growth media and incubation conditions. Subsequent isolate dereplication using MALDI-TOF mass spectrometry and identification of representative isolates through sequence analysis of protein encoding and 16S rRNA genes revealed the presence of established and novel dairy lactic acid bacteria, as well as bacteria that are considered indicators of poor hygienic conditions and psychrotrophic spoilage organisms. The large numbers of Lactococcus and Enterococcus isolates obtained present an interesting resource for starter culture selection.


Asunto(s)
Bacterias/aislamiento & purificación , Camelus/fisiología , Enterococcus/aislamiento & purificación , Leche/microbiología , Alimentos Crudos/microbiología , Animales , Bacterias/clasificación , Bacterias/genética , Enterococcus/genética , Microbiología de Alimentos , Lactobacillales/genética , Lactobacillales/aislamiento & purificación , Marruecos , ARN Ribosómico 16S/genética , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción
20.
Int J Food Microbiol ; 341: 109068, 2021 Mar 02.
Artículo en Inglés | MEDLINE | ID: mdl-33498009

RESUMEN

Raw vegetables are a key food for a healthy diet, but their increased consumption brings a higher risk for foodborne disease. Contamination of salad greens with Shiga toxin-producing Escherichia coli (STEC) O157:H7 has caused severe disease and important economic losses almost yearly in the United States over the last 10 years. To curb the risk of infections from contaminated produce, approaches based on bacterial virus - commonly known as bacteriophage or phage - have recently started to draw interest among other antimicrobial strategies. Phages enter bacterial cells to reproduce and cause cellular lysis to release their phage progeny at the end of their infection cycle. This lytic effect is caused by lysins, phage-encoded enzymes that have evolved to degrade the bacterial cell wall resulting in hypotonic lysis. When applied externally in their purified form, such enzymes are able to kill sensitive bacteria on contact in a similar way. Their unique bactericidal properties have made lysins effective antimicrobial agents in a variety of applications, from treating multidrug-resistant infections in humans to controlling bacterial contamination in several areas, including microbiological food safety. Here we describe a novel lysin, namely PlyEc2, with potent bactericidal activity against key gram-negative pathogens including E. coli, Salmonella, Shigella, Acinetobacter and Pseudomonas. PlyEc2 displayed high bactericidal activity against STEC to a concentration of 12.5 µg/ml under different pH conditions. This lysin was also able to reduce the bacterial titer of several pathogenic strains in vitro by more than 5 logarithmic units, resulting in complete sterilization. Importantly, PlyEc2 proved to be a powerful produce decontamination agent in its ability to clear 99.7% of contaminating STEC O157:H7 in our Romaine lettuce leaf model. PlyEc2 was also able to eradicate 99.8% of the bacteria contaminating the washing solution, drastically reducing the risk of cross-contamination during the washing process. A sensory evaluation panel found that treatment with PlyEc2 did not alter the visual and tactile quality of lettuce leaves compared to the untreated leaves. Our study is the first to describe a highly effective lysin treatment to control gram-negative pathogenic contamination on fresh lettuce without the addition of membrane destabilizing agents.


Asunto(s)
Antibacterianos/farmacología , Bacteriófagos/enzimología , Escherichia coli O157/efectos de los fármacos , Enfermedades Transmitidas por los Alimentos/prevención & control , Lechuga/microbiología , Bacteriófagos/metabolismo , Recuento de Colonia Microbiana , Descontaminación/métodos , Contaminación de Alimentos/análisis , Microbiología de Alimentos/métodos , Inocuidad de los Alimentos/métodos , Enfermedades Transmitidas por los Alimentos/microbiología , Humanos , Alimentos Crudos/microbiología
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