Browsing Articles publicats (Tecnologia, Enginyeria i Ciència dels Aliments) by Author "Alegre Vilas, Isabel"
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- ItemOpen AccessAloe vera gel: An update on its use as a functional edible coating to preserve fruits and vegetables(Elsevier, 2021) Nicolau Lapeña, Iolanda; Colás Medà, Pilar; Alegre Vilas, Isabel; Aguiló-Aguayo, Ingrid; Muranyi, Peter; Viñas Almenar, InmaculadaAloe vera L. is a common succulent plant that has been used for centuries regarding their healing properties and health benefits. Nowadays, scientific investigations on its gel have gained more attention because of its interesting antioxidant and antimicrobial properties. Also, the food industry encounters the need to preserve safety and quality of fresh produce; fruits and vegetables are in high demand due to their reported health benefits, and fresh-cut products are a new trend that meets the restless needs of the society. Edible coatings are an effective way to maintain freshness of these products, extend their shelf life, and even act as an alternative to modified atmosphere packaging to be used in conventional packaging. Aloe vera gel is a natural hydrocolloid, composed mainly by polysaccharides, that has been applied in the last years on fruits and vegetables. It can act as a semipermeable barrier for gases and water vapor, decreasing the respiration and ripening processes of the fruit, thus maintaining weight, firmness and valuable compounds. Its antioxidant and antimicrobial properties make it also an interesting material for increasing the shelf-life of fruits and vegetables. This review aims to describe the preparation and preservation of Aloe vera gel as well as the properties and compounds that are effective against oxidation and microbial growth. Moreover, the recent findings of its use – with or without additives – as an edible coating on fruits and vegetables have been widely detailed, showing that Aloe vera gel is a promising preservative method in this industry.
- ItemRestrictedAn Enterobacteriaceae species isolated from apples controls foodborne pathogens on fresh-cut apples and peaches(Elsevier, 2012) Alegre Vilas, Isabel; Viñas Almenar, Inmaculada; Usall i Rodié, Josep; Anguera, Marina; Figge, Marian J.; Abadias i Sero, Mª IsabelCurrently, chlorine is the most widely used decontaminant in the minimally processed (MP) food industry. However, it does not achieve more than a 1–2 log reduction in bacterial populations. Efficient decontamination of MP produce could create a less competitive environment in which pathogens can multiply without restriction. Therefore, our objective was to test the efficacy of the biopreservative bacterial strain CPA-6 isolated from MP apples to control a non-pathogenic strain of Escherichia coli O157:H7, Salmonella and Listeria innocua on MP apples and peaches. Apple and peach plugs were co-inoculated with a suspension containing one of the pathogens (105 colony forming units (cfu) plug−1) and CPA-6 (106 cfu plug−1) and incubated at 20 °C or 5 °C. CPA-6 effectively inhibited the growth of, or reduced, in some cases to below the limit of detection, pathogen populations on both fruit incubated for 2 days at 20 °C and of E. coli on both fruit incubated at 5 °C, compared with the pathogen inoculated alone. The minimum effective dose required to inhibit any of the pathogens tested was 106 cfu plug−1 on both fruit and at both temperatures and it did not cause a hypersensitive reaction on tobacco plants. Finally, CPA-6 could not be assigned to any of the recognised species within the family Enterobacteriaceae based on phenotypic and 16S rRNA results. Therefore, this strain may be a suitable microorganism to use as a biopreservative culture to control the growth of food borne pathogens on MP fruit.
- ItemRestrictedAntagonistic effect of Pseudomonas graminis CPA-7 against foodborne pathogens in fresh-cut apples under simulated commercial conditions(Elsevier, 2013) Alegre Vilas, Isabel; Viñas Almenar, Inmaculada; Usall i Rodié, Josep; Abadias i Sero, Mª Isabel; Altisent Rosell, Rosa; Anguera, MarinaRecently, we reported that the application of the strain CPA-7 of Pseudomonas graminis, previously isolated from apple, could reduce the population of foodborne pathogens on minimally processed (MP) apples and peaches under laboratory conditions. Therefore, the objective of the present work was to find an antioxidant treatment and a packaging atmosphere condition to improve CPA-7 efficacy in reducing a cocktail of four Salmonella and five Listeria monocytogenes strains on MP apples under simulated commercial processing. The effect of CPA-7 application on apple quality and its survival to simulated gastric stress were also evaluated. Ascorbic acid (2%, w/v) and N-acetyl-l-cysteine (1%, w/v) as antioxidant treatments reduced Salmonella, L. monocytogenes and CPA-7 recovery, meanwhile no reduction was observed with NatureSeal® AS1 (NS, 6%, w/v). The antagonistic strain was effective on NS-treated apple wedges stored at 10 °C with or without modified atmosphere packaging (MAP). Then, in a semi-commercial assay, efficacy of CPA-7 inoculated at 105 and 107 cfu mL−1 against Salmonella and L. monocytogenes strains on MP apples with NS and MAP and stored at 5 and 10 °C was evaluated. Although high CPA-7 concentrations/populations avoided Salmonella growth at 10 °C and lowered L. monocytogenes population increases were observed at both temperatures, the effect was not instantaneous. No effect on apple quality was detected and CPA-7 did not survived to simulated gastric stress throughout storage. Therefore, CPA-7 could avoid pathogens growth on MP apples during storage when use as part of a hurdle technology in combination with disinfection techniques, low storage temperature and MAP.
- ItemOpen AccessBacterial Spore inactivation in orange juice and orange peel by ultraviolet-C light(MDPI, 2021-04-15) Colás Medà, Pilar; Nicolau Lapeña, Iolanda; Viñas Almenar, Inmaculada; Neggazi, Isma; Alegre Vilas, IsabelSpore-forming bacteria are a great concern for fruit juice processors as they can resist the thermal pasteurization and the high hydrostatic pressure treatments that fruit juices receive during their processing, thus reducing their microbiological quality and safety. In this context, our objective was to evaluate the efficacy of Ultraviolet-C (UV-C) light at 254 nm on reducing bacterial spores of Alicyclobacillus acidoterrestris, Bacillus coagulans and Bacillus cereus at two stages of orange juice pro13 duction. To simulate fruit disinfection before processing, orange peel was artificially inoculated with each of the bacterial spores and submitted to UV-C light (97.8-100.1 W/m2) with treatment times between 3 s and 10 min. The obtained product, the orange juice, was also tested by exposing artificially inoculated juice to UV-C light (100.9-107.9 W/m2 16 ) between 5 and 60 min. A three-minute treatment (18.0 kJ/m2 17 ) reduced spore numbers on orange peel around 2 log units, while more than 45 min (278.8 kJ/m2 18 ) were needed to achieve the same reduction in orange juice for all evaluated bacterial spores. As raw fruits are the main source of bacterial spores in fruit juices, reducing bacte20 rial spores on fruit peels could help fruit juice processors to enhance microbiological quality and safety of fruit juices.
- ItemOpen AccessBioconservación frente a patógenos de transmisión alimentaria en frutas y hortalizas mínimamente procesadas(Consejo Superior de Investigaciones Científicas (CSIC), 2020-03) Alegre Vilas, Isabel; Abadias i Sero, Mª Isabel; Colás Medà, Pilar; Collazo Cordero, Cyrelys; Viñas Almenar, InmaculadaEl aumento en la producción y consumo de frutas y hortalizas mínimamente procesadas de los últimos años ha contribuido a incrementar las toxiinfecciones alimentarias asociadas al consumo de productos vegetales frescos. Esto es debido a que los tratamientos desinfectantes llevados a cabo actualmente por industria de IV gama son insuficientes para garantizar la seguridad microbiológica de los productos finales, y además estos no reciben ningún tratamiento capaz de eliminar todos los patógenos antes de su consumo. Por lo tanto, es necesario utilizar estrategias alternativas para reducir los microorganismos patógenos y alterantes en frutas y hortalizas. La bioconservación, mediante el uso de microorganismos o sus metabolitos, es una alternativa que, en combinación con las prácticas habituales, puede reducir o prevenir el crecimiento de patógenos en productos mínimamente procesados, mejorando su calidad microbiológica. En este artículo se presentan los resultados más relevantes sobre la bioconservación de frutas y hortalizas mínimamente procesadas.
- ItemRestrictedChanges in the quality and antioxidant properties of fresh-cut melontreated with the biopreservative culture Pseudomonas graminis CPA-7 during refrigerated storage(Elsevier B.V., 2016) Plaza, Lucía; Altisent Rosell, Rosa; Alegre Vilas, Isabel; Viñas Almenar, Inmaculada; Abadias i Sero, Mª IsabelThe strain CPA-7 of Pseudomonas graminis, isolated from apple by our group, was reported to reduce the population of foodborne pathogens in minimally processed fruit. The aim of this work was to investigate its effect on physical parameters, visual quality, enzymatic activity, vitamin C content and antioxidant activity of fresh-cut melon during refrigerated storage. CPA-7 treated or untreated fresh-cut melon was packaged under air or modified atmosphere (MAP) and stored at 5 and 10 °C for 8 days. Results showed a loss of texture during storage, above all at 10 °C. A good visual quality was observed for samples stored at 5 °C, although samples treated with the antagonistic strain CPA-7 and stored in air presented the lowest score, whereas those stored at 10 °C showed a poor visual appearance and a decrease of lightness. In general, CPA-7 treated samples presented higher POD values than untreated ones at 5 °C, and lower values at 10 °C. PPO increased during refrigerated storage regardless of the addition of the antagonist. Also, treatment with the antagonistic strain CPA-7 retained the antioxidant activity and vitamin C content of fresh-cut melon during refrigerated storage.
- ItemRestrictedComparative study of improved vs. traditional apple cultivars and their aptitude to be minimally processed as "ready to eat" apple wedges(Elsevier, 2014) Altisent Rosell, Rosa; Plaza, Lucía; Alegre Vilas, Isabel; Viñas Almenar, Inmaculada; Abadias i Sero, Mª IsabelThe development of fresh-cut apple products requires the reconsideration of cultivar selection because different characteristics are required compared with those characteristics for the fresh market. The aim of this work was to evaluate four improved cultivars ('Modì', 'Ariane', 'Fuji Kiku 8' and 'Pink Lady') and to compare these cultivars with traditional cultivars ('Golden Smoothee' and 'Granny Smith'). Cultivars were evaluated according to physicochemical parameters and nutritional, enzymatic, and sensory aspects. Next, the cultivars were peeled, cut, treated with different antioxidant treatments, packaged in polypropylene trays and stored at 4 °C. After seven days of storage, physicochemical parameters and visual assessment were determined. As whole apples, the improved cultivars were notable for their sensory characteristics. Moreover, two of them ('Modì' and 'Ariane') presented the highest amount of total phenols and vitamin C, respectively. After processing and storage, certain of the improved cultivars presented better aptitude for minimal processing. For instance, 'Modì' showed high suitability, and 'Fuji Kiku 8' was notable for its sensory quality after seven days of refrigerated storage. Among antioxidant treatments that were assayed, 40 g/L NatureSeal® demonstrated the best results in terms of physicochemical parameters, visual assessment and sensory quality.
- ItemOpen AccessControl biológico de las enfermedades fúngicas en poscosecha de fruta. Situación actual y perspectivas futuras(Interempresas Media, 2022-06-14) Viñas Almenar, Inmaculada; Colás Medà, Pilar; Nicolau Lapeña, Iolanda; Alegre Vilas, IsabelTradicionalmente el control de las enfermedades fúngicas en poscosecha de frutas se ha venido realizando mediante fungicidas químicos de síntesis. Sin embargo, la fuerte demanda por parte de los consumidores de fruta libre de residuos de plaguicidas y las nuevas estrictas regulaciones sobre su registro y aplicación, han propiciado la aparición de alternativas a los productos químicos. Dentro de las alternativas, el control biológico se presenta como una de las más prometedoras. En los últimos 35 años de investigación de los agentes de biocontrol en poscosecha se han llevado a cabo considerables avances y la comercialización de algunos productos. No obstante, todavía existen numerosos desafíos y obstáculos que dificultan la implementación de su uso como una estrategia de control a gran escala.
- ItemOpen AccessControl de patógenos de transmisión alimentaria en fresas congeladas y listas para el consumo(SPE3 s.l., 2020-03-11) Viñas Almenar, Inmaculada; Valero, A.; Gimeno Añó, Vicente; López Fructuoso, Mª Luisa; Aguiló-Aguayo, Ingrid; Abadias i Sero, Mª Isabel; Alegre Vilas, Isabel; Colás Medà, Pilar; Bobo, Gloria; Lafarga, Tomás; Posada, G. D.; Vallesquino, P.; Cejudo, M.; Ortiz Solà, Jordi; Nicolau Lapeña, Iolanda; Pérez-Lavalle, L.Estrategias de mitigación de los problemas asociados a la presencia de patógenos de transmisión alimentaria para la mejora de la calidad e inocuidad en la obtención de fresas congeladas y listas para el consumo.
- ItemRestrictedControl of foodborne pathogens on fresh-cut fruit by a novel strain of Pseudomonas graminis(Elsevier, 2013) Alegre Vilas, Isabel; Viñas Almenar, Inmaculada; Usall i Rodié, Josep; Teixidó i Espasa, Neus; Figge, Marian J.; Abadias i Sero, Mª IsabelThe consumption of fresh-cut fruit has substantially risen over the last few years, leading to an increase in the number of outbreaks associated with fruit. Moreover, consumers are currently demanding wholesome, fresh-like, safe foods without added chemicals. As a response, the aim of this study was to determine if the naturally occurring microorganisms on fruit are “competitive with” or “antagonistic to” potentially encountered pathogens. Of the 97 and 107 isolates tested by co-inoculation with Escherichia coli O157:H7, Salmonella and Listeria innocua on fresh-cut apple and peach, respectively, and stored at 20 °C, seven showed a strong antagonistic capacity (more than 1-log unit reduction). One of the isolates, CPA-7, achieved the best reduction values (from 2.8 to 5.9-log units) and was the only isolate able to inhibit E. coli O157:H7 at refrigeration temperatures on both fruits. Therefore, CPA-7 was selected for further assays. Dose-response assays showed that CPA-7 should be present in at least the same amount as the pathogen to adequately reduce the numbers of the pathogen. From the results obtained in in vitro assays, competition seemed to be CPA-7's mode of action against E. coli O157:H7. The CPA-7 strain was identified as Pseudomonas graminis. Thus, the results support the potential use of CPA-7 as a bioprotective agent against foodborne pathogens in minimally processed fruit.
- ItemOpen AccessDevelopment of a fresh-cut product based on pears and the subsequent evaluation of its shelf life under commercial conditions and after a cold chain break(Science and Education Publishing, 2016) Colás Medà, Pilar; Abadias i Sero, Mª Isabel; Altisent Rosell, Rosa; Alegre Vilas, Isabel; Plaza, Lucía; Gilabert, V.; Lacomba, R.; Viñas Almenar, InmaculadaProcessing of pears as a fresh-cut product could offer added value and introduce a product into the market that offers greater convenience and health benefits for consumers. Cultivar selection is one of the most important considerations for fresh-cut fruit processing because characteristics such as flesh texture, skin colour, and browning potential can vary greatly among cultivars. Four pear cultivars (‘Flor de invierno’, ‘Passe-Crassane’, ‘Ercolini’ and ‘Conference’) and four antioxidant treatments, that is, (NS) 50 g L-1 NatureSeal® AS1 (Agricoat) solution, (AsAc) 20 g L-1 ascorbic acid + 10 g L-1 citric acid + 10 g L-1 calcium chloride solution, (CaAs) 20 g L-1 calcium ascorbate + 10 g L-1 calcium chloride solution and (NaAs) 20 g L-1 sodium ascorbate + 10 g L-1 calcium chloride solution, were tested to obtain a high-quality fresh-cut pear. For the selected cultivar and treatment, the nutritional changes and physicochemical, microbial and sensorial quality were evaluated under conditions that simulated commercial application followed by storage at 4 °C and a simulated cold chain break at 8°C. The ‘Conference’ pear was selected as the best cultivar based on its physicochemical characteristics (high levels of soluble solids content and low acidity), low increase in browning index, and visual acceptance after 7 days of storage. The results demonstrated that CaAs maintained the fresh-cut pear quality after 8 days of storage at 4°C and also after a cold chain break. Furthermore, application of the selected treatment produced an increase in the ascorbic acid content, total phenolic content and antioxidant activity of minimally processed pear samples. These values were reduced during shelf life, but the total phenolic content at the final sampling point was higher than that of fresh-cut pears after processing without treatment.
- ItemOpen AccessEffect of ripeness stage during processing on Listeria monocytogenes growth on fresh-cut "Conference" pears(Elsevier, 2015) Colás Medà, Pilar; Abadias i Sero, Mª Isabel; Alegre Vilas, Isabel; Usall i Rodié, Josep; Viñas Almenar, InmaculadaThere are several factors that affect the shelf life of fresh-cut fruit, including the cultivar, the ripeness stage of the fruit during processing and the fruit's storage atmosphere and temperature. The effect of fruit ripeness during processing on the survival and growth of Listeria monocytogenes on fresh-cut 'Conference' pear slices at different temperatures (5, 10 and 20 °C) was studied. The four ripeness stages studied in this work (assessed by a fruit's firmness) were mature-green (54
60 N), partially ripe (43
53 N), ripe (31
42 N) and overripe (<31 N). In our studies, pH, acidity and soluble solids content did not significantly change during conditioning at 20 °C. L. monocytogenes grew under all experimental conditions, showing an increase of approximately 2 log CFU g−1 after 8 days of storage at 5 °C. There were significant differences in the L. monocytogenes population between different ripeness stages at the end of the experiments at 10 and 20 °C. Regardless of the ripeness stage of a fresh-cut pear, the growth potential of L. monocytogenes increased with increasing temperature. A pear's ripeness stage during processing is an important consideration to ensure the quality of a fresh-cut pear, but it is not as important for preventing L. monocytogenes growth at common storage temperatures.
- ItemOpen AccessEvaluation of commercial anti-listerial products for improvement of food safety in ready-to-eat meat and dairy products(MDPI, 2023-02-19T23:00:00Z) Colás Medà, Pilar; Viñas Almenar, Inmaculada; Alegre Vilas, IsabelIn ready-to-eat products, such as cooked ham, fresh cheese, and in which is a concern, the use of biopreservation techniques represents an additional hurdle to inhibit pathogen growth during storage. The objective of this study was to apply several biopreservation techniques in three different food matrices to reduce the growth of , used as a surrogate of . Several lactic acid bacteria, the bacteriocin nisin, the bacteriophage PhageGuard Listex P100, and the enzyme lysozyme were evaluated. Cooked ham treated with the bacteriophage PhageGuard Listex at 0.5% or with the lactic acid bacteria SafePro B-SF-43 (25 g/100 kg) reduced population to below the detection limit after 7 days of storage (4 °C plus modified atmosphere packaging). In fresh cheese, the application of PhageGuard Listex at 0.2 and 0.5% reduced counts by more than 3.4 logarithmic units after 6 days at 4 °C. In , the 1.0% of PhageGuard Listex reduced population by 0.7 ± 0.2 logarithmic units in front of control with no significant differences to other evaluated biopreservative agents. The present results confirm that the application of biopreservation techniques was able to inhibit in , cooked ham, and fresh cheese, and suggest that the type of food matrix and its physicochemical characteristics influence the biopreservative efficacy.
- ItemOpen AccessInactivation of Escherichia coli, Salmonella enterica and Listeria monocytogenes on apple peel and apple juice by ultraviolet C light treatments with two irradiation devices(Elsevier, 2022) Nicolau Lapeña, Iolanda; Colás Medà, Pilar; Viñas Almenar, Inmaculada; Alegre Vilas, IsabelFollowing the market trends, the consumption of fresh and cold-pressed juice in Europe is increasing. However, a primary concern – particularly in apple juice – is the related outbreaks caused by food-borne pathogens. One of the challenges is to find methods able to reduce pathogenic loads while avoiding deterioration of nutritional properties and bioactive compounds that occur in thermal pasteurization processes. In this study, the inactivation of Escherichia coli, Salmonella enterica and Listeria monocytogenes was evaluated under different ultraviolet C (UVC254nm) light treatments (up to 10,665.9 ± 28.1 mJ/cm2), in two different steps of the production chain (before and after juice processing): on apple peel discs and in apple juice. The systems proposed were a horizontal chamber with UVC254nm emitting lamps treating the product disposed at a distance of 12 cm, and a tank containing UVC254nm lamps and in which the product is immersed and agitated. Final reductions ranged from 3.3 ± 0.5 to 5.3 ± 0.4 logarithmic units, depending on the microorganism, matrix and used device. The survival curves were adjusted to Weibull and biphasic models (R2-adj ≥ 0.852), and UVC doses needed for the first decimal reduction were calculated, being lower for the apple peel discs (0.20 to 83.83 mJ/cm2) than they were for apple juice (174.60 to 1273.31 mJ/cm2), probably for the low transmittance of the apple juice compared to the surface treatment occurring on the peels. Within the treatments evaluated, the UVC254nm irradiation of apple peels immersed in water was the best option as it resulted in a reduction of the tested microorganisms of ca. 2–3 log units at lower UVC254nm doses (< 500 mJ/cm2) when compared to those occurring in apple peel treated with the UVC chamber and in juice. As contamination can proceed from apples, the sanitization of these fruit prior to juice production may be helpful in reducing the safety risks of the final product, reducing the drawbacks related to the poor transmittance of the fruit juices.
- ItemOpen AccessOccurrence of Alicyclobacillus acidoterrestris in pasteurized and high hydrostatic pressure-treated fruit juices and isolates' characterization(Elsevier, 2023) Neggazi, Isma; Colás Medà, Pilar; Viñas Almenar, Inmaculada; Garza Garza, Salvador; Alegre Vilas, IsabelIn recent years, acidophilic, heat-resistant, and spore-forming spoilage bacteria have been identified in pasteurized or treated by high hydrostatic pressure (HPP) fruit juices. Alicyclobacillus acidoterrestris is the bacteria more frequently linked to the spoilage of this type of product because its spores can survive conventional pasteurization and HPP treatments. Under favourable conditions, such as an acidic pH, its spores can germinate and multiply, with the consequent production of guaiacol. Guaiacol is a compound with an undesirable odour (“medicinal”, “smoked” or “antiseptic”). In this context, our objective was to determine the prevalence of A. acidoterrestris in 150 Spanish pasteurized and HPP-treated fruit juices purchased from supermarkets or received from manufacturers. Then, the isolates and the reference strain (CECT 7094 T) were characterized to establish differences in terms of (i) growth capacity at different pH and temperatures, and in (ii) guaiacol production capacity. The results showed a high incidence of A. acidoterrestris (18.0 %) in the analysed juices. The 44.4 % of the isolates came from blends of fruit juices. Within juice blends, 9 juices contained apple juice among their ingredients. This represents a 18.8 % of incidence with respect to the total of blended juices with apple. A high incidence in monovarietal apple juices was also observed (3 out of 14 samples). Regarding the characterization of the isolates, EC1 (isolated from an apple concentrate) showed the highest growth capacity at pH 4.0 at temperatures from 20 to 55 °C. Besides, three strains (R42, EC10, and EZ13, isolated from clementine, plum and white grape juice, respectively) could grow at room temperatures (20 and 25 °C). For pH, only EZ13, isolated from white grape juice, was able to grow significantly at pH 2.5. Finally, the production of guaiacol ranged from 74.1 to 145.6 ppm, being the isolate EC1 the one that produced more guaiacol after 24 h of incubation at 45 °C (145.6 ppm). As we have observed, there is a high incidence of A. acidoterrestris in marketed juices and intermediate products despite the treatments received (pasteurization or HPP). Under favourable conditions for the development of this microorganism, it could produce enough guaiacol to spoil the juices before their consumption. Therefore, in order to improve the quality of fruit juices it is necessary to investigate in more detail the origin of this microorganism and to find strategies to reduce its presence in final products.
- ItemOpen AccessPathogenic potential of the surviving Salmonella Enteritidis on strawberries after disinfection treatments based on ultraviolet-C light and peracetic acid(Elsevier, 2022-01-10) Ortiz Solà, Jordi; Colás Medà, Pilar; Nicolau Lapeña, Iolanda; Alegre Vilas, Isabel; Abadias i Sero, Mª Isabel; Viñas Almenar, InmaculadaFresh fruits, especially strawberries, are usually consumed raw without any step to ensure their food safety. Salmonella enterica is one of the most important etiologic agents for foodborne diseases throughout the world and its ability to respond to some stress responses makes it even more dangerous. In the present investigation, we study the survival of S. Enteritidis (CECT-4300) on strawberries after 2-min of various disinfection steps (NaClO (200 ppm), peracetic acid (PAA; 40 ppm), water-assisted UV-C (WUV-C), and the combination WUV-C and 40 ppm of PAA (WUV-C + PAA)) and after 5 days of cold storage (4 °C). Moreover, the pathogenic potential of the surviving bacteria, such as the ability to survive throughout the gastrointestinal tract (GI) and subsequently the capability to adhere to and invade Caco-2 cells, was tested at each sampling point. After 2-min of washing procedures, reductions of S. Enteritidis on strawberries were ≥1.2 log, with no significant differences among treatments. However, the use of WUV-C + PAA treatment achieved the highest reductions in washing water, in which S. Enteritidis was not detected (
- ItemOpen AccessPotencial de la radiación ultravioleta para el control de podredumbres en postcosecha de frutas y hortalizas(Phytoma-España, 2021-10) Alegre Vilas, Isabel; Colás Medà, Pilar; Nicolau Lapeña, Iolanda; Viñas Almenar, InmaculadaSe estima que más de un 20% de las frutas y hortalizas se desperdician antes de su consumo, siendo las podredumbres fúngicas una de las principales causas. El uso de la radiación ultravioleta puede ser una alternativa a los fungicidas químicos que está mostrando resultados prometedores, ya sea actuando directamente sobre el moho o incrementado la resistencia de los vegetales a las podredumbres. A continuación, se revisarán los avances más recientes sobre el uso de la radiación ultravioleta en frutas y hortalizas.
- ItemOpen AccessStudies on the biocontrol mechanisms of Pseudomonas graminis strain CPA-7 against food-borne pathogens in vitro and on fresh-cut melon(Elsevier, 2017) Collazo Cordero, Cyrelys; Abadias i Sero, Mª Isabel; Aguiló-Aguayo, Ingrid; Alegre Vilas, Isabel; Chenoll, Empar; Viñas Almenar, InmaculadaThe present study was aimed at gaining insight into the mode of action of the antagonistic bacteria Pseudomonas graminis CPA-7, which has been previously identified as an effective biocontrol agent against Listeria monocytogenes, Salmonella enterica and Escherichia coli O157:H7 on fresh-cut fruit. In vitro experiments did not reveal any antimicrobial or proteolytic activity on solid media or any biosurfactant activity on hydrophobic surfaces. Metabolites produced by CPA-7 in two different culture media and on 'Galia' melon were unable to inhibit L. monocytogenes populations on 'Galia' melon plugs at 25 °C or 5 °C. In contrast, at 25 °C the population of this pathogen on 'Galia' plugs was reduced by 2.1 and 3.3 log-units when co-inoculated with the antagonist in water, after 24 and 48 h, respectively. CPA-7 did not form biofilms after 72 h at 25 °C (OD = 0.03) or at 30 °C (OD = 0.01) on polystyrene plates and the production of alginate was close to the negative control. Studies of nutritional profiles showed high overlap (NOI > 0.9) between CPA-7 and E. coli O157:H7 regarding the use of carboxylic acids. This functional group could also contain putative targets for competiveness between CPA-7 and S. enterica, although overlapping was not restrictive enough (NOI = 0.83).
- ItemOpen AccessThe impact of a cold chain break on the survival of Salmonella enterica and Listeria monocytogenes on minimally processed ‘Conference’ pears during their shelf life(Wiley, 2016) Colás Medà, Pilar; Viñas Almenar, Inmaculada; Alegre Vilas, Isabel; Abadias i Sero, Mª IsabelBACKGROUND: In recent years, improved detection methods and increased fresh-cut processing of produce have led to an increased number of outbreaks associated with fresh fruits and vegetables. During fruit and vegetable processing, natural protective barriers are removed and tissues are cut, causing nutrient rich exudates and providing attachment sites for microbes. Consequently, fresh-cut produce ismore susceptible to microbial proliferation than whole produce.
- ItemOpen AccessUltraviolet applications to control patulin produced by penicillium expansum CMP-1 in Apple products and study of further patulin degradation products formation and toxicity(Springer, 2022) Nicolau Lapeña, Iolanda; Rodríguez Bencomo, Juan José; Colás Medà, Pilar; Viñas Almenar, Inmaculada; Sanchís Almenar, Vicente; Alegre Vilas, IsabelPatulin is a mycotoxin whose presence in apple-derived products and fruit juices is legally regulated, being its maximum limits established in the legislation of multiple countries. However, the management of contaminated batches is still an issue for producers. This investigation aims to evaluate ultraviolet light (254 nm, UV-C254nm) irradiation to find solutions that can be applied at different stages of the apple juice production chain. In this regard, 8.8 (UV-1) and 35.1 (UV-2) kJ m−2 treatments inactivated spores of Penicillium expansum CMP-1 on the surface of apples. Although the same treatments applied to wounded apples (either before the infection or after the infection, immediately or when the lesion had appeared) did not show any effect on the growth rate of P. expansum during storage (up to 14 days, at 4 or 25 °C), they reduced patulin content per lesion size in apples treated after the infection had occurred (patulin decreased from 2.24 (control) to 0.65 µg kg−1 cm−2 (UV-2 treated apples)). Additionally, the treatment of juice with patulin with ultraviolet light up to 450.6 kJ m−2 resulted in more than 98 % reduction of patulin. Degradation products of patulin after UV-C254nm treatments were tentatively identified by HPLC–MS, and toxicity and biological activities were assessed in silico, and results indicated that such products did not pose an increased risk when compared to patulin.