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1.
Meat Sci ; 216: 109572, 2024 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-38970932

RESUMEN

Growing health and environmental concerns have increased demand for all-natural products, with a focus on clean labelling. Sodium nitrite is the most widely used additive in the meat industry because it imparts the typical cured flavour and colour to meat products and, most importantly, their microbiological safety. However, due to health concerns, the European Commission is proposing revised regulations to reduce nitrate and nitrite levels in meat products. As a result, the meat industry is actively seeking alternatives. This study explored the production of four cooked hams utilising nitrate-rich vegetable sources combined with two different nitrate-reducing commercial food cultures, alongside a control ham prepared with sodium nitrite (150 ppm). Microbiological, physico-chemical (pH, water activity, nitrate and nitrite concentration, lipid profile, lipid oxidation) and sensory (texture and colour profile) characterisation of the products was carried out. Challenge tests for Listeria monocytogenes, Clostridium sporogenes and Clostridium perfringens have been performed to assess the growth of pathogens, if present in the products. Results revealed comparable microbiological and physico-chemical profiles across ham formulations, with minor differences observed in colour parameters for sample C. The sensory analysis showed that for the pilot ham formulations A and D, there were no significant differences in consumer perception compared to the control ham. In the challenge tests, L. monocytogenes levels were similar in both control and tested hams. There were no significant differences in C. sporogenes and C. perfringens counts at any temperature or between test and control samples. These results indicate that this technology has a potential future in the cured meat sector, as regulators mandate the reduction of added synthetic chemicals and consumers seek healthier and more natural ingredients in their daily diets.


Asunto(s)
Microbiología de Alimentos , Productos de la Carne , Nitratos , Nitrito de Sodio , Productos de la Carne/microbiología , Productos de la Carne/análisis , Animales , Nitrito de Sodio/química , Nitratos/análisis , Humanos , Porcinos , Comportamiento del Consumidor , Listeria monocytogenes , Color , Etiquetado de Alimentos , Proyectos Piloto , Manipulación de Alimentos/métodos , Gusto , Clostridium perfringens , Verduras/química
2.
Foods ; 13(2)2024 Jan 20.
Artículo en Inglés | MEDLINE | ID: mdl-38275695

RESUMEN

This study explores the potential of thermosonication as an alternative to traditional heat treatments, such as pasteurization, in the processing of fruit juices. Conventional methods often lead to undesirable quality changes in fruit juices, whereas thermosonication offers promising results regarding microbial inactivation and quality preservation. This work focused on the inactivation kinetics of Listeria innocua 2030c, a surrogate for pathogenic L. monocytogenes, in kiwifruit juice using thermosonication at 45 °C, 50 °C, and 55 °C. These treatments were compared with equivalent heat treatments. Quality attributes of the juice were also evaluated to assess process efficiency. Survival data of L. innocua were fitted with the Weibull model, estimating first decimal reduction times (δ) and shape parameters (n). The results reveal temperature and process dependencies on δ, while n remains mostly temperature and treatment independent. Thermosonication outperforms heat treatment, achieving higher L. innocua reductions while retaining quality attributes like pH, soluble solid content, and total phenolics and chlorophylls. Thermosonication at 55 °C stands out, providing a 6.2-log-cycle reduction in just 3 min with superior quality retention. These findings highlight the synergistic effect of temperature and ultrasound, making mild heat processes feasible while enhancing product quality. Thermosonication, particularly at 55 °C, emerges as an effective alternative to traditional thermal treatments for fruit juices, offering improved microbial safety without compromising product quality.

3.
Foods ; 12(7)2023 Mar 23.
Artículo en Inglés | MEDLINE | ID: mdl-37048174

RESUMEN

The 2030 Sustainable Development Agenda calls for all social actors to contribute to significant societal and environmental issues [...].

4.
Foods ; 12(3)2023 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-36766150

RESUMEN

The peels of many fruits are rich sources of nutrients, although they are not commonly consumed. If they are properly decontaminated, they can be used as healthy food ingredients reducing food waste. The objective was to apply thermosonication processes to kiwi peel and evaluate the impact on Listeria innocua survival (a non-pathogenic surrogate of L. monocytogenes) and key nutrients and quality indicators: proteins, fibers, minerals (Ca, K, Mg, Na, and P), chlorophylls, and phenolic contents. Kiwi peels were artificially inoculated with L. innocua and thermal and thermosonication treatments were performed at 55 °C and 60 °C for 30 and 15 min maximum, respectively. Bacteria were enumerated through treatment time, and quality indicators were assessed before and at the end of treatments. A Weibull model with a decimal reduction time (D-value) was successfully used in L. innocua survival data fits. Results showed that coupling temperature to ultrasound had a synergistic effect on bacteria inactivation with significant decreases in D-values. Thermosonication at 60 °C was the most effective in terms of protein, fiber, chlorophylls, and phenolics retention. Minerals were not significantly affected by all treatments. Applying thermosonication to kiwi peel was more effective for decontamination than thermal treatments at the same temperature while allowing the retention of healthy compounds.

5.
J Sci Food Agric ; 103(3): 1127-1138, 2023 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-36085567

RESUMEN

BACKGROUND: EU policies towards a circular economy address plastic packaging as one of the significant concerns and sets ambitious recycling targets. Polyolefins (POs) cannot be recycled for food contact using conventional polyethylene terephthalate (PET) recycling approaches. Thermal degradation prevents the use of high temperatures and, consequently, decontamination of POs may be insufficient when using lower temperatures. Polypropylene (PP) beverage cups were decontaminated using supercritical fluid extraction with carbon dioxide (scCO2 ). Decontamination efficiencies (DEs) of selected markers were determined in challenge tests following European Food Safety Authority guidelines. The effects of time (10-60 min) for PET, polylactic acid (PLA), and PP and temperature (60-80 °C) for PP were studied at constant pressure. The physical properties, sensorial properties, and overall migration of treated scCO2 PP were analysed and compared with virgin PP. RESULTS: PP showed the highest average DE, and PET the lowest, for all the surrogates and in all time conditions. A relative increase in the DE with the increase in process time, particularly for PET and to some extent for PLA, was seen. For PP, no significant impact of time and temperature was observed under the conditions tested. The DE of volatile surrogates was higher than that of semi-volatiles. Results indicate that the scCO2 treatment did not affect the physical and sensorial properties, nor the overall migration of PP, although it contributes to a considerable reduction in extractable n < C24 alkanes. CONCLUSIONS: Results indicate that scCO2 can be used to decontaminate post-consumption PP beverage cups with higher DEs than those for PET and PLA, applying mild processing conditions. © 2022 Society of Chemical Industry.


Asunto(s)
Tereftalatos Polietilenos , Polipropilenos , Polipropilenos/análisis , Tereftalatos Polietilenos/análisis , Dióxido de Carbono , Bebidas/análisis
6.
Children (Basel) ; 9(11)2022 Nov 19.
Artículo en Inglés | MEDLINE | ID: mdl-36421227

RESUMEN

Psychomotor intervention has been used to promote development by the enhancement of psychomotor and socio-emotional competence. However, studies with high-quality evidence, describing psychomotor-intervention processes and outcomes are scarce. Therefore, we aimed to generate expert consensus regarding psychomotor-intervention guidelines to support psychomotor therapists through the design and implementation of interventions for preschool (3−6 years old) children with autism spectrum disorder (ASD). A formal consensus process was carried out, using modified nominal group (phase I) and Delphi survey (phase II) techniques. We recruited 39 Portuguese experts in psychomotor intervention with preschool children with ASD in phase I. Experts participated in at least one of the five online meetings, discussing themes (e.g., objectives, methods, strategies) concerning psychomotor intervention with preschool children with ASD. A deductive thematic analysis from phase I resulted in 111 statements composing round 1 of the Delphi survey. Thirty-five experts completed round 1, and 23 round 2. The experts reached a consensus (agreement > 75%) on 88 statements, grouped under 16 sections, (e.g., intervention source, general setting, intended facilitation-style), reflecting generic psychomotor-intervention guidelines. Consensus guidelines may be used to support transparent and standard psychomotor interventions, although further studies should be undertaken to determine their efficacy.

7.
Foods ; 11(9)2022 Apr 27.
Artículo en Inglés | MEDLINE | ID: mdl-35563995

RESUMEN

Carob fruit is native to the Mediterranean region and produced mainly in Portugal, Italy, Morocco and Turkey. The production of the carob fruit in Portugal is highly extensive and sustainable. Currently, carob flour (CF) production is mainly achieved after pulp separation, despite it having been demonstrated that the seeds improve the extraction efficiency of bioactive compounds such as polyphenols, promoting human health. This study aimed to produce an integral CF through an innovative process and assess its physicochemical and bioactive properties at different particle sizes throughout simulated gastrointestinal tract (GIT) digestion. The sugar content profile obtained throughout GIT digestion indicated that sucrose, the sugar present at the highest concentration in undigested CF, was digested and broken down into simple sugars, namely glucose and fructose. The total phenolic content (TPC) and antioxidant activity obtained for the ≤100 µm fraction were in accordance and gastric digestion promoted an increase in the TPC value compared to the undigested sample. The >100 µm fractions displayed a distinct profile from the ≤100 µm fraction. This study showed that the particle size affects the sugar, antioxidant and total phenolic content of CFs and also their gastrointestinal tract digestion. The ≤100 µm fraction demonstrated the most suitable profile as a functional food ingredient.

8.
Foods ; 11(10)2022 May 21.
Artículo en Inglés | MEDLINE | ID: mdl-35627069

RESUMEN

Melon peel is recognized as a source of healthy nutrients and oxidant compounds. Being considered a non-edible part with no profit value, large amounts of melon rinds are discharged by fruit industries. Innovative food ingredients with potential health benefits may arise if these parts were conveniently transformed. The objective was to freeze-dry small melon peel cubes to attain a potential edible matrix. An ozone pre-treatment was applied seeking decontamination purposes and quality retention. The effect of these processes was assessed in terms of physicochemical parameters (moisture content, water activity and color), bioactive compounds (total phenolics, vitamin C and chlorophylls) and antioxidant capacity, during 7 weeks of storage at room temperature. Intrinsic microflora (mesophylls, yeasts and molds) were also monitored. Results showed that the freeze-drying process allowed retention of the most bioactive compounds analyzed, except for total phenolic content. In this case, the ozone pre-treatment was important for phenolics preservation. During the storage period, ozonated samples presented a higher content of bioactive compounds. In terms of microflora, the ozone and freeze-drying effects were not significant. Freeze-drying proved to be a suitable preservation method for melon peel. The ozone impact was not relevant in terms of decontamination.

9.
Foods ; 10(4)2021 Mar 30.
Artículo en Inglés | MEDLINE | ID: mdl-33808125

RESUMEN

Fruit waste parts, particularly peel, are abundant sources of bioactive compounds. To be included in the formulation of value-added foods, peel needs to be transformed and subjected to a preservation process. Therefore, this study seeks to assess the effect of ozone on the quality and antilisterial indicators of cantaloupe melon peel paste, aiming at obtaining a product with the potential to be used as a food additive. Ozone was bubbled during 30 and 60 min, and some physicochemical characteristics (soluble solids content, pH and colour), bioactive compounds (total phenolics, chlorophylls and vitamin C) and antioxidant activity were analysed. Peel was also inoculated with Listeria innocua, used as a treatment efficiency indicator. The results indicated that, although ozone negatively affected antioxidant activity, it positively influenced all bioactive compounds analysed. An L. innocua reduction of 1.2 log cycle was achieved after ozone exposure. Ozone should be exploited as a promising technology to assure the quality/safety of cantaloupe melon peel. Indeed, if melon peel is conveniently converted into a suitable form that can be used as a food ingredient, this will promote the valorisation of waste materials with the consequent reduction of industrial by-products and new perspectives for market opportunities.

10.
Foods ; 10(4)2021 Mar 25.
Artículo en Inglés | MEDLINE | ID: mdl-33805929

RESUMEN

BACKGROUND: A wide variety of social, cultural and economic factors may influence dietary patterns. This work aims to identify the main determinants of food consumption and barriers for healthy eating at the workplace, in a university setting. METHODS: A cross-sectional observational study was conducted with 533 participants. Data were obtained through the application of a self-administered questionnaire that included socio-demographic information, food consumption determinants and the main perceived barriers for healthy eating at the workplace. RESULTS: The respondents identified "price" (22.5%), "meal quality" (20.7%), and "location/distance" (16.5%). For women, the determinant "availability of healthy food options" was more important than for men (p < 0.001). The food consumption determinants at the workplace most referred to by respondents were related to the nutritional value. Smell, taste, appearance and texture, and good value for money, were also considered important for choosing food at the workplace. Respondents referred to work commitments and lack of time as the main barriers for healthy eating at the workplace. CONCLUSIONS: Identification of determinants involved in food consumption, and the barriers for healthy eating, may contribute to a better definition of health promotion initiatives at the workplace aiming to improve nutritional intake.

11.
Eur J Case Rep Intern Med ; 7(7): 001491, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32665920

RESUMEN

Listeria monocytogenes is a gram positive bacillus responsible for listeriosis. This infection manifests mainly as bacteremia and / or central nervous system (CNS) infection. Involvement of other sites is rare. Pleural listeriosis is an uncommon presentation of L. monocytogenes infection and there is little data to guide the management of these patients. First-line antibiotics used empirically to treat bacterial respiratory infections are ineffective in treating these L. monocytogenes infections, which contributes to the progression of the infection and a worse prognosis. We present a case report of a patient admitted to an intensive care unit with septic shock secondary to systemic listeriosis with L. monocytogenes isolation in pleural fluid culture and blood cultures. The evolution of the hospitalization and the clinical outcome are reported. LEARNING POINTS: Pleural listeriosis is an infection rarely observed in clinical practice.It is typically found in immunosuppressed patients.Delay in the identification of this microorganism and the empirical use of inappropriate antibiotics may lead to an adverse outcome.

12.
Acta Med Port ; 33(4): 252-260, 2020 Apr 01.
Artículo en Portugués | MEDLINE | ID: mdl-32238239

RESUMEN

INTRODUCTION: Transgenic (genetically modified) foods are being grown, sold and eaten in Portugal. As such it is important that physicians stay up to date on any negative health consequences of such foods. This study aimed to identify their opinion, knowledge and training needs regarding transgenic foods. MATERIAL AND METHODS: A total of 278 physicians responded to a survey Results: In terms of opinion, 85.8% of physicians had a neutral position, 12.5% had a negative view and a minority (1.7%) was positive. However, 79.8% had a low level of knowledge, 17.7% had an average level of knowledge and only 2.5% showed a high level of knowledge regarding the subject. It should be noted that 91.4% of physicians consider that it is useful to carry out some kind of training during their university education and 65.1% said that it would be very useful during the professional life to have continuing education concerning the issue. Most physicians (83%) could be grouped together according to their interest in learning more. The other group (17%) showed lack of interest. DISCUSSION: Physicians are considered reliable sources, to whom the general population can turn to in order to access valuable health information, which suggests the need to stay up-to-date regarding transgenic foods. CONCLUSION: This is a pioneering study on Portuguese physicians and transgenic foods. Results point to a need for specific training concerning this issue.


Introdução: Há alimentos transgénicos (modificados geneticamente) a serem cultivados, comercializados e consumidos em Portugal. É importante que os médicos se mantenham ao corrente quanto aos impactos de tais alimentos na saúde. Este trabalho propõe-se identificar a opinião, conhecimento e necessidades de formação dos médicos face aos alimentos transgénicos.Material e Métodos: Foi aplicado um inquérito a 278 médicos.Resultados: Em relação à opinião, 85,8% apresentam uma posição neutra, 12,5 % negativa e uma minoria (1,7%) positiva. No entanto, 79,8% têm um nível de conhecimento baixo, 17,7% médio e 2,5% alto. De referir que 91,4% consideram útil existir algum tipo de formação durante a educação universitária e 65,1% destacaram ser muito útil ao longo da vida profissional a existência de formação continuada sobre esta temática. Emergiram dois perfis de médicos: um grupo (83%), interessado em saber mais sobre alimentos transgénicos e outro grupo (17%), desinteressado.Discussão: Os médicos são considerados fontes de referência fiável a quem a população opta por recorrer para obter informação sobre saúde, o que sugere a necessidade de se manter um conhecimento suficiente e atualizado sobre este tema.Conclusão: Este estudo é pioneiro no que se refere ao posicionamento de médicos portugueses relativamente a estes alimentos. Os resultados apontam para uma necessidade de formação específica.


Asunto(s)
Alimentos Modificados Genéticamente , Conocimientos, Actitudes y Práctica en Salud , Evaluación de Necesidades , Médicos/psicología , Adulto , Actitud del Personal de Salud , Educación Médica Continua , Femenino , Humanos , Masculino , Persona de Mediana Edad , Médicos/estadística & datos numéricos , Portugal , Encuestas y Cuestionarios
13.
Food Microbiol ; 87: 103351, 2020 May.
Artículo en Inglés | MEDLINE | ID: mdl-31948609

RESUMEN

The objective of this work was to investigate the effect of stress conditions frequently encountered in food-associated environments on virulence-associated characteristics of eight strains of Listeria monocytogenes. Strains were grown at low (11 °C, cold stress) and optimal (37 °C) temperatures and in high NaCl concentrations (6% NaCl, 11 °C; cold-osmotic stress) and tested for their ability to invade the human intestinal epithelial Caco-2 cells. Results demonstrate that the correlation between exposure to cold stress and increased invasion phenotype is strain-dependent as strains investigated exhibited different behaviours, i.e. exposure to cold stress conditions resulted in a significant increase of invasion levels in five out of the eight strains tested, when compared to growth under optimal conditions. On the other hand, when these cold-adapted cells were subsequently submitted to high salt concentrations and low temperature, their enhanced ability to invade Caco-2 was lost. Surprisingly, saturated fatty acids (SFA) and branched chain fatty acids (BCFA) decreased when L. monocytogenes were exposed to stress conditions as opposed to what has been observed in other studies, therefore highlighting that further studies will need to deepen in the understanding of the lipid metabolism of these strains. The effect of stress conditions on the survival of three selected L. monocytogenes strains through an in vitro gastrointestinal (GI) tract digestion model was further investigated. The exposure to cold-osmotic stress increased the survival of one strain through the GI tract.


Asunto(s)
Listeria monocytogenes/fisiología , Listeriosis/microbiología , Adaptación Fisiológica , Células CACO-2 , Frío , Recuento de Colonia Microbiana , Humanos , Listeria monocytogenes/química , Listeria monocytogenes/crecimiento & desarrollo , Listeria monocytogenes/patogenicidad , Presión Osmótica , Cloruro de Sodio/metabolismo , Estrés Fisiológico , Virulencia
14.
Food Microbiol ; 85: 103282, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-31500713

RESUMEN

Two biopreservation approaches for fresh lettuce, rocket salad, parsley and spinach were studied. The potential of Pediococcus pentosaceus DT016, as a protective culture, to suppress Listeria monocytogenes in vegetables during storage was evaluated. The pathogen numbers in the vegetables inoculated with P. pentosaceus DT016 were significantly (p < 0.01) lower throughout the storage period and, at the last storage day, a minimum difference of 1.4 log CFU/g was reported when compared with the vegetables without the protective culture. Moreover, by using two levels of L. monocytogenes (about 6 and 4 log CFU/g), it was observed that the antagonist effect of P. pentosaceus was higher for the lower pathogen numbers. The second approach evaluated a pediocin DT016 solution to inactivate and control L. monocytogenes proliferation. The pathogen load was studied after washing with: water, chlorine and the pediocin solution and along storage at 4  °C. Comparing the various washing solutions, the vegetables washed with pediocin presented significantly (p < 0.01) lower pathogen numbers throughout storage, by a minimum of 3.2 and 2.7 log CFU/g, than in vegetables washed with water and chlorine, respectively. The proposed methodologies are promising alternatives to maintain the safety of fresh vegetables during extended storage at refrigeration temperature.


Asunto(s)
Antibiosis , Microbiología de Alimentos/métodos , Conservación de Alimentos/métodos , Listeria monocytogenes/fisiología , Verduras/microbiología , Carga Bacteriana , Cloro/farmacología , Frío , Seguridad de Productos para el Consumidor , Manipulación de Alimentos/métodos , Lactuca/microbiología , Listeria monocytogenes/efectos de los fármacos , Listeria monocytogenes/crecimiento & desarrollo , Pediocinas/farmacología , Pediococcus pentosaceus/fisiología , Petroselinum/microbiología , Refrigeración , Spinacia oleracea/microbiología , Agua
15.
Food Microbiol ; 86: 103315, 2020 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-31703881

RESUMEN

Non-thermal food processing and replacement of chemical additives by natural antimicrobials are promising trends in the food industry. The objective of the present work was to evaluate the effect of a process which combines mild high hydrostatic pressure - HHP (200 and 300 MPa, 5 min, 10 °C), phage Listex™ P100 and the bacteriocin pediocin PA-1 as a new non-thermal process for destruction of Listeria monocytogenes (104 CFU mL-1 or 107 CFU mL-1) in milk. For inoculum levels of 104 CFU mL-1, HHP combined with phage P100 eliminated L. monocytogenes immediately after pressurization. When L. monocytogenes was inoculated at levels of 107 CFU mL-1, a synergistic effect between phage P100, pediocin PA-1 and HHP (300 MPa) on the inactivation of L. monocytogenes was observed during storage of milk at 4 °C. For non-pressure treated samples inoculated with phage or pediocin or both, L. monocytogenes counts decreased immediately after biocontrol application, but regrowth was observed in a few samples during storage. Phage particles were stable during refrigerated storage for seven days while pediocin PA-1 remained stable only during three days. Further studies will have to be performed to validate the findings of this work in specific applications (e.g. production of raw milk cheese).


Asunto(s)
Bacteriófagos/fisiología , Conservación de Alimentos/métodos , Conservantes de Alimentos/farmacología , Listeria monocytogenes/efectos de los fármacos , Listeria monocytogenes/virología , Leche/microbiología , Pediocinas/farmacología , Animales , Bovinos , Recuento de Colonia Microbiana , Conservación de Alimentos/instrumentación , Presión Hidrostática , Listeria monocytogenes/química , Listeria monocytogenes/crecimiento & desarrollo
16.
J Food Sci Technol ; 56(6): 3090-3098, 2019 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-31205363

RESUMEN

A protein isolate (ERPI) was prepared from ethanol-treated rapeseed meal and used as a stabilizing agent in sunflower and rapeseed oil-in-water emulsions. The aim of the current study was to explore the influence of protein and oil concentrations on initial stability of sunflower and rapeseed oil-in-water emulsions by evaluating Gibbs free energy (ΔG) and particle size distribution. The 7-day dynamics of emulsion stability was investigated by turbidity measurement as well. A 32 factorial design was applied to assess the significance of oil (5%, 10% and 15% w/w) and ERPI protein (0.25%, 0.5% and 1.0% w/w) addition on stability of the emulsions. The results demonstrated that the increase of oil concentrations from 5 to 15% positively influenced the initial stability of sunflower and rapeseed oil-in-water emulsions. In both oil types, ERPI protein supplementation at all levels resulted in significant differences in the stability of 5% and 10% oil emulsions but did not alter the initial stability of the emulsions prepared with either 15% sunflower or rapeseed oil. With a few exceptions, there was a good agreement between Gibbs free energy data and microstructural profiles of the emulsions. Overall, emulsions with all sunflower oil concentrations and 1.0% ERPI protein exhibited better initial and a 7-day stability dynamics compared to all rapeseed oil-based emulsions. The study demonstrated the potential of ethanol-treated rapeseed meal protein isolate to serve as an emulsifying agent in sunflower and rapeseed oil containing emulsions.

17.
Food Microbiol ; 76: 416-425, 2018 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-30166169

RESUMEN

The application of lytic phages as biocontrol agents is emerging as a promising strategy towards elimination or reduction of foodborne pathogens in a variety of food products. This technology is particularly advantageous for minimally processed and ready-to-eat (RTE) foods. In this study, the potential use of Listex™ P100 combined with high hydrostatic pressure (HPP), to enhance the control of Listeria monocytogenes in food was evaluated. For that, the effect of three pressures (200, 300 or 400 MPa; 5 min, 10 °C) on phage P100 stability was tested when inoculated in six different matrices: phosphate buffered saline (PBS, pH 7.4); apple juice (pH 3.41); orange/carrot nectar (pH 3.54); UHT whole milk (pH 6.73); and, two traditional Portuguese fermented products, "Serra da Estrela" cheese (pH 5.66) and "Alheira", a meat sausage (pH 6.07). The results showed that treatment at 400 MPa reduced phage titres to below the detection level in all matrices, whereas at milder pressures the survival of the phage was matrix dependent. "Alheira", "Serra da Estrela" cheese and UHT whole milk were shown to be baroprotective matrices that support phage P100 application in HHP up to 300 MPa; however, an accentuated phage inactivation was observed in apple and orange/carrot nectar, which may be related to the acidic pH values of these matrices. The initial phage load did not affect the inactivation rate during HHP processing (300 MPa, 5 min, 10 °C) in PBS, cheese, sausage or milk matrices, and the phage titres were stable in these matrices during storage at 4 °C for 28 days for milk and 60 days for "Alheira" and "Serra da Estrela" cheese. In addition, a baroprotective effect on phage stability was observed when PBS was supplemented with reducing sugars, dextrin, casein, and tween 80. In conclusion, at mild HHP treatment, phage P100 remained active in specific matrices and seems to present potential to be added in non-thermal inactivation of L. monocytogenes.


Asunto(s)
Bacteriófagos/fisiología , Queso/microbiología , Comida Rápida/microbiología , Conservación de Alimentos/métodos , Jugos de Frutas y Vegetales/microbiología , Listeria monocytogenes/virología , Productos de la Carne/microbiología , Leche/microbiología , Animales , Contaminación de Alimentos/prevención & control , Conservación de Alimentos/instrumentación , Presión Hidrostática , Listeria monocytogenes/fisiología
18.
Foodborne Pathog Dis ; 10(10): 861-6, 2013 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-23909772

RESUMEN

The aim of this study was to characterize a broad collection of isolates of Listeria monocytogenes, of different serotypes, recovered in Portugal between 2003 and 2007 from foods (n=353) and from clinical cases of human listeriosis (n=95), in terms of antimicrobial susceptibility. All the isolates were susceptible to ampicillin, the preferred agent to treat listeriosis. Resistances to nitrofurantoin (n=99), to ciprofloxacin (n=18), to erythromycin (n=10), to tetracycline (n=2), to gentamicin (n=1) and to rifampicin (n=1) were observed. One hundred (28.3%) and 20 (21.0%) food and clinical isolates, respectively, were resistant to at least one antibiotic. Eight isolates (1.8%) were resistant to two or more antimicrobials of different classes, and all were collected from foods. Serogroup IVb included the highest percentage of isolates resistant to erythromycin. The highest percentages of isolates resistant to nitrofurantoin were of serogroup IVb and IIc. It was demonstrated that the incidence of antibiotic-resistant isolates of L. monocytogenes, during the period 2003 to 2007, was low in Portugal but still higher than that observed in other countries. Given the increasing population at greater risk of listeriosis, namely, the elderly, the high mortality rate of the infection and the detection of resistant isolates, monitoring for antibiotic resistance in strains of L. monocytogenes on a large scale, and assessing the risk of infection by these strains, is highly recommended.


Asunto(s)
Antibacterianos/farmacología , Farmacorresistencia Bacteriana , Microbiología de Alimentos , Listeria monocytogenes/efectos de los fármacos , Listeriosis/epidemiología , Anciano , Humanos , Listeria monocytogenes/clasificación , Listeria monocytogenes/aislamiento & purificación , Listeriosis/microbiología , Pruebas de Sensibilidad Microbiana , Reacción en Cadena de la Polimerasa Multiplex , Portugal/epidemiología
19.
J AOAC Int ; 96(1): 33-6, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-23513954

RESUMEN

Ethylene oxide gas is commonly used to sterilize medical devices, and concerns about using this agent on biological systems are well-established. Medical devices sterilized by ethylene oxide must be properly aerated to remove residual gas and by-products. In this work, kinetics of ethylene oxide desorption from different sterilized materials were studied in a range of aeration temperatures. The experimental data were well-described by a Fickian diffusion mass transfer behavior, and diffusivities were estimated for two textile and two polymeric materials within the temperature range of 1.5 to 59.0 degrees C. The results will allow predictions of ethylene oxide desorption, which is a key step for the design of sterilization/aeration processes, contributing to an efficient removal of residual ethylene oxide content.


Asunto(s)
Óxido de Etileno/química , Esterilización , Difusión , Cinética
20.
J Water Health ; 10(1): 1-10, 2012 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-22361697

RESUMEN

This study aimed at assessing the role of ubiquitous (non-Escherichia coli) Enterobacteriaceae in the dissemination of antimicrobial resistance through the urban water cycle. Enterobacteriaceae isolated from a municipal wastewater treatment plant (111 isolates), urban water streams (33 isolates) and drinking water (123 isolates) were compared in terms of: (i) genera distribution, (ii) resistance to 12 antibiotics, and (iii) class 1 and class 2 integrons. The predominant bacterial genera were the same in the different types of water, although with a distinct pattern of species. The most prevalent resistance phenotypes were observed for amoxicillin, ticarcillin, cephalothin and sulphamethoxazole (24-59% in the three types of water). No resistance against ceftazidime or meropenem was observed. Resistance to cephalothin, amoxicillin and sulphamethoxazole was significantly more prevalent in drinking water, water streams and wastewater, respectively, than in the other types of water. It was possible to recognize antibiotic-resistance associations, namely for the pairs streptomycin-tetracycline (positive) and ticarcillin-cephalotin (negative). Class 1 and/or class 2 integrons with similar gene cassettes were detected in the three types of water. This study demonstrated that Enterobacteriaceae are important vehicles of antibiotic resistance, namely in drinking water.


Asunto(s)
Antibacterianos/farmacología , Agua Potable/microbiología , Farmacorresistencia Microbiana , Enterobacteriaceae/efectos de los fármacos , Enterobacteriaceae/aislamiento & purificación , Agua Dulce/microbiología , Microbiología del Agua , Distribución de Chi-Cuadrado , Enterobacteriaceae/genética , Integrones/genética , Pruebas de Sensibilidad Microbiana , Fenotipo , Portugal , Eliminación de Residuos Líquidos
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