Agrotecnio Center

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https://repositori.udl.cat/handle/10459.1/56965

Agrotecnio aims to become a reference in Europe addressing all the key elements of the food production chain in an integrated way focusing on target crops and animals of commercial importance, rather than model systems. This later aspect sets our centre apart from other centers which focus on fundamental science and/or model plant and animal systems. As a result we should be able to address fundamental and important questions in the crop/animal of interest and results from our research will be directly and immediately applicable to our target organism. [Més informació]

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Adhesion and invasion of Listeria monocytogenes and interaction with Lactobacillus rhamnosus GG after habituation on fresh-cut pear
(Elsevier Ltd, 2017-07) Iglesias Valenzuela, María Belén; Viñas Almenar, Inmaculada; Colás Medà, Pilar; Collazo Cordero, Cyrelys; Serrano Casasola, José Carlos Enrique; Abadias i Sero, Mª Isabel
Several foods are carriers of probiotic bacteria. Most species of the genus Lactobacillus are probiotics and common inhabitants of the human gastrointestinal tract. It is known that they contribute to the health of gastrointestinal tract, but at the same time certain strains can be antagonistic against foodborne pathogens. In this study, we evaluated the effect of Lactobacillus rhamnosus GG on the ability of a strain of Listeria monocytogenes serovar 4b to survive passage through the gastrointestinal tract, and its adhesion and invasion into Caco-2 cells when it was previously habituated on fresh-cut pear stored at 10 °C for 7 days. At the end of the storage, L. rhamnosus GG caused a reduction in the survival of L. monocytogenes in the gastrointestinal tract, and adhesion and invasion into Caco-2 cells. Moreover, it showed an antagonistic activity against L. monocytogenes.
Open Access
An innovative water-assisted UV-C disinfection system to improve the safety of strawberries frozen under cryogenic conditions
(Elsevier, 2021) Ortiz Solà, Jordi; Viñas Almenar, Inmaculada; Aguiló-Aguayo, Ingrid; Bobo, Gloria; Abadias i Sero, Mª Isabel
Strawberries inoculated with Salmonella enterica, Listeria monocytogenes (108 CFU/mL, 50 μL) and murine norovirus (MNV-1; 106 TCID50/mL, 50 μL), were washed for 2 min in a water-assisted UV-C light tank (WUVC) combined or not with 40 mg/L of peracetic acid (WUVC+PA), and 200 mg/L of free chlorine solution (NaClO) with the UV-C lamps switched off. Moreover, a ‘conventional’ dry UV-C treatment (DUVC) was also tested. After 2-min exposure, washing sanitization with chemical agents gave the highest reduction for both bacteria (ca. ≥ 3.3 log CFU/g) and MNV-1 (≥1.8 log TCID50/mL). DUVC treatment proved to be the least effective technology (≤0.6 log CFU/g for bacteria and 1.5 log TCID50/mL for MNV-1). Regarding wash water, no presence of L. monocytogenes and S. enterica were reported with WUVC+PA and NaClO sanitization. After disinfection, samples were frozen at − 70 ± 2 ◦C in a cryogenic freezing cabinet with liquid nitrogen (N2). For both pathogens, frozen storage after washing substantially enhanced their inactivation in the first 3 days (1.1–4.9 log UFC/g) compared to the reductions obtained the following sampling points (0.0–0.8 log UFC/g). After 90 days, L. monocytogenes and S. enterica were not detected on the samples treated with water-assisted methodologies (WUVC, WUVC+PA and NaClO treatments), whilst MNV-1 was little affected. Further studies are needed to improve norovirus inactivation on frozen strawberries. Industrial relevance: The present work provides relevant information to the frozen food industry regarding a suitable decontamination alternative to chlorine sanitation. Low-dose immersion-assisted UV-C allows inactivation and inhibition of pathogenic microbiota while generates non-toxic byproducts and allows reusing the process water, contributing to the so-called “smart green growth” attended to provide a more innovative and sustainable future for the food industry.
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Antagonistic effect of probiotic bacteria against foodborne pathogens on fresh-cut pear
(Elsevier Ltd, 2017-08) Iglesias Valenzuela, María Belén; Abadias i Sero, Mª Isabel; Anguera, Marina; Sabata, J.; Viñas Almenar, Inmaculada
The use of probiotics as biopreservation agents of foodborne pathogens in food is becoming increasingly known. The aim of this work was to investigate the effectiveness of Lactobacillus rhamnosus GG (L rham. GG) and Lactobacillus acidophilus LA-5 (L. acidophilus LA-5) against Salmonella and Listeria monocytogenes in minimally processed pears during storage at 5, 10 and 20 degrees C at conditions simulating commercial application. Pear wedges were artificially inoculated with a suspension containing Salmonella, L. monocytogenes and/or the probiotic strains L rham. GG or L. acidophilus LA-5, packaged and stored at 5, 10 and 20 degrees C. Microorganisms were periodically enumerated. L acidophilus LA-5 did not shown any effect against pathogens. Salmonella was affected by co-inoculation with L. than GG at 10 and 20 C, which reduced the population approximately 2-log units. Moreover, L. monocytogenes population was reduced approximately 3-log units at each temperature in presence of L rham. GG. Probiotic populations were maintained throughout the experiment around 10(7)-10(8) CFU g(-1), which is in the range known to develop its probiotic role (10(6)-10(9) CFU g(-1)). Our results demonstrated that L. rham. GG is able to control Salmonella and L monocytogenes growth on fresh-cut pear.
Open Access
Application of an innovative water-assisted ultraviolet C light technology for the inactivation of microorganisms in tomato processing industries
(Elsevier, 2021) Abadias i Sero, Mª Isabel; Colás Medà, Pilar; Viñas Almenar, Inmaculada; Bobo, Gloria; Aguiló-Aguayo, Ingrid
We aimed to study the efficacy of a water-assisted UVC light device (WUVC) as an innovative clean technology for the disinfection of fresh sound tomatoes and processing wash water and water turbidity was evaluated as a critical parameter. First, wash waters with different turbidities (from 0.4 to 828 NTU) were inoculated with Listeria innocua and treated in the WUVC device at different dosages. Secondly, fresh tomatoes, inoculated with L. innocua and non-inoculated ones, were treated using the WUVC device containing wash water of different turbidities for different times. The reduction of L. innocua populations on wash water and on the surface of tomato was influenced by turbidity; lower reduction values were observed at higher turbidities. Washing tomatoes with tap water with UVC lamps off (control treatment, TW) decreased L. innocua population on the surface of tomatoes but did not eliminate those bacteria that went into the water. Contrarily, when UVC lights were on, L. innocua population in wash water after treatment significantly decreased, those in clean water being the lowest populations. Reductions of native microbiota on the clean water treated with the highest UV-C radiation dose were lower than those obtained when tomatoes were artificially inoculated. We demonstrated that high reductions of L. innocua population on fresh tomatoes could be achieved using the WUVC system but some drawbacks related to the increase of turbidity should be solved for its implementation in real conditions.
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Application of modified atmosphere packaging as a safety approach to fresh-cut fruits and vegetables
(Elsevier Ltd., 2015) Sousa Oliveira, Márcia Patrícia de; Abadias i Sero, Mª Isabel; Usall i Rodié, Josep; Torres Sanchis, Rosario; Teixidó i Espasa, Neus; Viñas Almenar, Inmaculada
This review provides an overview of the effect of modified atmosphere packaging (MAP) on the survival and growth of foodborne pathogens on fresh-cut fruits and vegetables. Substantial technological advances have been made in this area, mainly in improving the quality and shelf-life of minimally processed products. Nevertheless, attention must be paid on the survival and growth of pathogenic microorganisms that may be present in fruits and vegetables. Modified atmosphere packaging (MAP) in combination with refrigeration temperatures could be used as a mild preservation technique for safety of minimally processed fruits and vegetables. However, the effect of MAP on microorganisms can vary, depending mainly on the storage conditions and the type of packaged product.
Open Access
Assessing water-assisted UV-C light and its combination with peroxyacetic acid and Pseudomonas graminis CPA-7 for the inactivation and inhibition of Listeria monocytogenes and Salmonella enterica in fresh-cut 'Iceberg' lettuce and baby spinach leaves
(Elsevier, 2019) Collazo Cordero, Cyrelys; Noguera, Violeta; Aguiló-Aguayo, Ingrid; Abadias i Sero, Mª Isabel; Colás Medà, Pilar; Nicolau Lapeña, Iolanda; Viñas Almenar, Inmaculada
The effectiveness of ultraviolet C light (UV-C) delivered in water (WUV) or in peroxyacetic acid (PAA) for theinactivation and inhibition ofL. monocytogenesandS. entericain ready-to-eat'Iceberg lettuce'and baby spinachleaves, was evaluated throughout chilled storage in modified atmosphere packaging (MAP). The inhibition ofpathogen's growth by sequential pretreatments with UV-C in PAA and then biocontrol usingPseudomonas gra-minisCPA-7 was assessed during MAP storage at 5 °C and upon a breakage of the cold-storage chain. In fresh-cutlettuce, 0 1 kJ/m2UV-C, in water or in 40 mg/L PAA, inactivated both pathogens by up to 2.1 ± 0.7 log10,which improved the efficacy of water-washing by up to 1.9 log10and showed bacteriostatic effects on bothpathogens. In baby spinach leaves, the combination of 0 3 kJ/m2UV-C and 40 mg/L PAA reducedS. entericaandL. monocytogenespopulations by 1.4 ± 0.2 and 2.2 ± 0.3 log10respectively, which improved water-washing by0.8 ± 0.2 log10. Combined treatments (0.1 or 0 3 kJ/m2WUV and 40 mg/L PAA) inactivated both pathogens inthe process solution from lettuce or spinach single sanitation, respectively. Pretreating lettuce with UV-C in PAAreducedL. monocytogenesandS. enterica's growth by up to 0.9 ± 0.1 log10with respect to the PAA-pretreatedcontrol after 6 d at 5 °C in MAP. Upon a cold-chain breakage, CPA-7 preventedS. entericagrowth in PAA-pretreated lettuce, whereas showed no effect onL. monocytogenesin any of both matrices. Low-dose UV-C in PAAis a suitable preservation strategy for improving the safety of ready-to-eat leafy greens and reducing the risk ofcross contamination.
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Biopreservation of fresh-cut melon using the strain Pseudomonas graminis CPA-7
(Elsevier B.V., 2014) Abadias i Sero, Mª Isabel; Altisent Rosell, Rosa; Usall i Rodié, Josep; Torres Sanchis, Rosario; Sousa Oliveira, Márcia Patrícia de; Viñas Almenar, Inmaculada
The use of biopreservation is a promising technique to ensure microbial safety of fresh-cut produce. The objective of this work was to test the effectiveness of the strain CPA-7 of Pseudomonas graminis against a cocktail of Salmonella spp. and Listeria monocytogenes on fresh-cut melon, and evaluate its effect on its quality during shelf-life when tested in conditions simulating commercial application. Fresh-cut melon was artificially inoculated with Salmonella spp. and L. monocytogenes and with or without the biopreservative strain at different concentrations and stored at 20, 10 and 5 °C. Moreover, the effect of the strain was tested in conditions simulating commercial application. Fresh-cut melon was packaged using passive modified atmosphere (MAP) and AIR conditions and stored at 5 and 10 °C. Quality of fresh-cut melon was evaluated in CPA-7 treated and untreated samples. At laboratory scale trials, P. graminis reduced Salmonella and L. monocytogenes growth on fresh-cut melon stored at 5, 10 and 20 °C. Effectiveness depended on their concentration and on storage temperature. At low pathogen concentration and 20 °C, L. monocytogenes growth was reduced between 2.1 and 5.3 log cfu g−1 units after 2 days of storage and Salmonella growth between 2.0 and 7.3 log cfu g−1 depending on CPA-7 dose. At 10 °C, similar reductions of pathogens were observed after 5 days of storage. In studies simulating commercial conditions, packaging atmosphere and temperature influenced P. graminis effectiveness, with better results in samples packaged under AIR conditions and 10 °C. Reduction of pathogen growth was <1-log unit in fresh-cut melon stored in MAP whilst it was >4-log units in AIR. Soluble solids content, titratable acidity, pH and firmness of fresh-cut melon were not significantly different in CPA-7 treated and untreated (control) melon. In general, lightness, chroma and hue values of fresh-cut melon stored in AIR decreased faster in CPA-7 samples than on control ones. At 5 °C, CPA-7 treated melon was visually scored lower than untreated melon. P. graminis has demonstrated promising results at 10 °C, which is a temperature more compromised for safety. Nevertheless more detailed studies on the modified atmosphere are required because AIR packaging is not recommended due to the rapid loss of quality.
Open Access
Biopreservation of fresh-cut pear using Lactobacillus rhamnosus GG and effect on quality and volatile compounds
(Elsevier, 2018-01) Iglesias Valenzuela, María Belén; Echeverría Cortada, Gemma; Viñas Almenar, Inmaculada; López Fructuoso, Mª Luisa; Abadias i Sero, Mª Isabel
In recent years, the consumption of minimally processed fruit has increased. However, unfortunately, these products could be an appropriate vehicle for the transmission of foodborne pathogens. In this study, the antagonistic capacity of the probiotic strain Lactobacillus rhamnosus GG against a cocktail of 5 serovars of Salmonella and 5 serovars of Listeria monocytogenes on fresh-cut pear at conditions simulating commercial application was assessed. Moreover, its effect on fruit quality, particularly on the volatile profile, was determined, during 9 days of storage at 5 °C. L. monocytogenes population was reduced by approximately 1.8 log-units when co-inoculated with L. rhamnosus GG. However, no effect was observed in Salmonella. Fruit quality (soluble solids content and titratable acidity) did not change when the probiotic was present. A total of 48 volatile compounds were identified using gas chromatography. Twelve of the compounds allowed to discriminate L. rhamnosus GG-treated and untreated pears. Considering their odour descriptors, their increases could be positive in the flavour perception of L. rhamnosus GG-treated pear. The probiotic was able to control L. monocytogenes population on fresh-cut pear, which could be a vehicle of probiotic microorganisms as quality of fruit was not affected when the probiotic was present.
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Biopreservative methods to control the growth of foodborne pathogens on fresh-cut lettuce
(Elsevier B.V., 2015) Sousa Oliveira, Márcia Patrícia de; Abadias i Sero, Mª Isabel; Colás Medà, Pilar; Usall i Rodié, Josep; Viñas Almenar, Inmaculada
Fruits and vegetables can become contaminated by foodborne pathogens such as Escherichia coli O157:H7, Salmonella and Listeria monocytogenes, and it has been demonstrated that current industrial sanitizing treatments do not eliminate the pathogens when present. Chemical control is widely used, but biological control appears to be a better solution, mainly using the native microbiota present on fresh produce. The first objective of this study was to isolate native microbiota from whole and fresh-cut produce and to determine whether these bacteria were antagonistic toward foodborne pathogens. A total of 112 putative antagonist isolates were screened for their ability to inhibit the growth of Salmonella enterica on lettuce disks. Five different genera reduced S. enterica growth more than 1-log unit at 20°C at the end of 3 days. When tested against L. monocytogenes 230/3, only Pseudomonas sp. strain M309 (M309) was able to reduce pathogen counts by more than 1-log unit. Therefore, M309 strain was selected to be tested on lettuce disks at 10°C against S. enterica, E. coli O157:H7 and L. monocytogenes. M309 strain was only able to reduce S. enterica and E. coli O157:H7 populations. The second objective was to test different biopreservative methods including M309 strain, Pseudomonas graminis CPA-7 (CPA-7), bacteriophages (Listex P100 and Salmonelex) and nisin at conditions simulating commercial applications against Salmonella and L. monocytogenes on fresh-cut lettuce. The addition of the biopreservative agents did not result in a significant reduction of Salmonella population. However, CPA-7 strain together with nisin reduced L. monocytogenes numbers after 6 days of storage at 10°C. The cocktail of Salmonella and L. monocytogenes was not markedly inactivated by their respective bacteriophage solutions. This study highlighted the potential of biocontrol, but the combination with other technologies may be required to improve their application on fresh-cut lettuce.
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Changes 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 Isabel
The 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.
Open Access
Combination of ferulic acid with Aloe vera gel or alginate coatings for shelf-life prolongation of fresh-cut apples
(Elsevier, 2021) Nicolau Lapeña, Iolanda; Aguiló-Aguayo, Ingrid; Kramer, Bernd; Abadias i Sero, Mª Isabel; Viñas Almenar, Inmaculada; Muranyi, Peter
Weight loss, microbial spoilage and enzymatic browning are the main quality-determining processes which limit the shelf-life of fresh-cut apples. In this study, two edible coatings based on Aloe vera gel (AV) and sodium alginate cross-linked with calcium lactate (AC), with the addition of 10 mg/mL ferulic acid (FA) as a functional ingredient, were developed in order to prolong the quality and safety of fresh-cut apple discs. Texture parameters, pH and Brix values and water activity did not undergo relevant changes related to the treatments. Except for weight loss, which was significantly lower for the coated samples, the addition of FA was found to be the most relevant factor for the other investigated parameters, including the total phenolic content and the antioxidant activity measured by ferric reducing antioxidant power (FRAP). Browning was delayed by the addition of FA and also by the AV coating, while non-coated and alginate coated samples showed the highest values in early stages. Although no effect on Saccharomyces cerevisiae was observed, FA treatments and alginate were effective in reducing Listeria monocytogenes populations by 2.3 ± 0.4 log CFU / g, which contributes to an enhanced product safety.
Open Access
Combination of sonication with anti-browning treatments as a strategy to increase the shelf life of fresh-cut potatoe (cv. Monalisa)
(Wiley, 2021) Nicolau Lapeña, Iolanda; Bobo, Gloria; Abadias i Sero, Mª Isabel; Viñas Almenar, Inmaculada; Aguiló-Aguayo, Ingrid
Abstract. Two antioxidant solutions, a patented mixture based on vitamin C and other compounds (Natureseal®, MV) and green tea extract (GT), were proposed to prevent browning in sliced potatoes. Combination with ultrasound (US) at two frequencies (35 and 130 kHz) was also evaluated, but no significant enhancement of the effects was detected with US. In MV-treated samples, respiration rate and dry matter (19.7%) were higher than they were in the control (CK) (17.3%) or GT-treated samples (16.8%). Neither membrane integrity nor malondialdehyde content was significantly affected by the addition of MV or GT, but in MV samples the antioxidant activity was increased sixfold at the beginning of the storage (39.1 mmol ascorbic acid equivalents/kg), but decreased after 9 days. A yellowish coloration on the surface of GT samples (L*a*b* values being 68.3, −6.4, and 25.3, respectively), attributed to the coloration of the tea concentrate, was observed. In the conditions studied, GT was not able to delay browning in potatoe slices. In contrast, MV solution preserved the original color of the sliced potatoes (69.6, −6.7, and 27.7 for L*a*b*, respectively), during the 9-day storage at 4°C. Novelty Impact Statement. Sulfites are used as an additive to maintain food color, shelf life, and prevent the growth of fungi or bacteria. However, they are considered as allergenic substances. The study proves the efficacy of vitamin C as a substitute to sulfites to preserve fresh-cut potatoes and delay their browning.
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Comparative 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 Isabel
The 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.
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Composition and properties of the polyphenolic extracts obtained from industrial plum pomaces
(Elsevier, 2015) Sójka, Michał; Kołodziejczyk, Krzysztof; Milala, Joanna; Abadias i Sero, Mª Isabel; Viñas Almenar, Inmaculada; Guyot, Sylvain; Baron, Alain
The polyphenol composition of purified extracts obtained from plum pomace gathered from production lines of a modern fruit transformation plant was characterized. The extraction of polyphenols from pomaces was performed using water. These water extracts were purified on an Amberlite polymer bed and freeze-dried. The resulting preparations were characterized by high polyphenol contents (up to 50 g/100 g) determined using spectrophotometric method with Folin–Ciocalteu reagent. The selected plum preparations were characterized by high flavanol contents (up to 10 g/100 g) and high antioxidant capacities. Additionally, significant amounts of hydroxycinnamic acids and flavonols were detected in the plum preparations. The bacteriostatic effects of the extracts were observed against Salmonella, Listeria and E. coli O157:H7. Two of the extracts had high bactericidal effects against Listeria. This research showed that plum pomaces are a good raw material for the production of highly-concentrated polyphenol preparations with potential biological properties.
Open Access
Control 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.
Open Access
Corrigendum to ‘Quality and bioaccessibility of total phenols and antioxidant activity of calçots (Allium cepa L.) stored under controlled atmosphere conditions’ Postharvest Biology and Technology 129 (2017) 118-128
(Elsevier, 2017) Zudaire Villanueva, Lorena; Viñas Almenar, Inmaculada; Abadias i Sero, Mª Isabel; Simó Cruanyes, Joan; Echeverría Cortada, Gemma; Plaza, Lucía; Aguiló-Aguayo, Ingrid
Open Access
Decontamination of fresh-cut broccoli with a water–assisted UV-C technology and its combination with peroxyacetic acid
(Elsevier, 2018) Collazo Cordero, Cyrelys; Lafarga, Tomás; Aguiló-Aguayo, Ingrid; Marín Sáez, Jesús; Abadias i Sero, Mª Isabel; Viñas Almenar, Inmaculada
The effectiveness of a water-assisted UV-C (WUV) technology for the decontamination of fresh-cut broccoli from conventional and organic agricultural practices was evaluated as an alternative to chlorine sanitation. Several WUV doses (0.3–1.8 kJ m−2) were tested alone or combined with peroxyacetic acid (PAA). Results showed that 0.5 kJ m−2 was sufficient to reduce natural total aerobic mesophilic microorganisms by 2 log10 in conventional broccoli without negative consequences on the physical quality. However, in order to achieve the same effect on organic broccoli, a combined application of at least 0.3 kJ m−2 and 50 mg L−1 PAA was required. Total antioxidant capacity (TAC) was enhanced by 42, 90 and 81% in conventional broccoli 24 h after treatment with 0.3, 0.5 and 1.8 kJ m−2, respectively, compared to water-control. A similar trend was observed in organic broccoli, although the increase in TAC (by 22%) compared to the water-control was only significant when a dose of 1.8 kJ m−2 was used. Similarly, 0.5 kJ m−2 enhanced the sulforaphane content in conventional broccoli by 1.5 and 4-fold compared to water and chlorine-controls, respectively. WUV is a promising alternative technology to improve the microbiological and nutritional quality of fresh-cut broccoli.
Open Access
Decontamination of Listeria innocua from fresh-cut broccoli using UV-C applied in water or peroxyacetic acid, and dry-pulsed light
(Elsevier, 2019-03) Collazo Cordero, Cyrelys; Charles, Florence; Aguiló-Aguayo, Ingrid; Marín Sáez, Jesús; Lafarga, Tomás; Abadias i Sero, Mª Isabel; Viñas Almenar, Inmaculada
The efficacy of two irradiation technologies: Ultraviolet-C light (UV-C), applied in water or in diluted peroxyacetic acid, and dry-pulsed light (PL) for the inactivation and growth inhibition of Listeria innocua in fresh-cut broccoli were evaluated. Water-assisted UV-C (WUV) (0.3 and 0.5 kJ/m2) reduced L. innocua initial populations by 1.7 and 2.4 log10 CFU/g, respectively; the latter dose also inhibited their growth for 8 d at 5 °C. Replacing water with 40 or 80 mg/L peroxyacetic acid did not improve this efficacy. Pulsed light (5, 10, 15, and 20 kJ/m2) showed no effect on native microbiota. Neither did 15 kJ/m2 PL inactivate L. innocua or inhibit its growth. Nonetheless, 24-h post-processing, PL (15 kJ/m2) increased total phenolic content by 25% in respect of chlorine-sanitation, and enhanced total antioxidant capacity by 12 and 18% compared to water and chlorine controls, respectively. Unlike dry-PL, WUV appears to be a suitable technology for controlling L. monocytogenes populations in fresh-cut broccoli.
Open Access
Development 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, Inmaculada
Processing 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.
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DNA-based methodologies to detect and quantify the postharvest biocontrol agent Pantoea agglomerans CPA-2 applied on oranges
(International Society for Horticultural Science, 2016-11) Soto Muñoz, Lourdes; Teixidó i Espasa, Neus; Usall i Rodié, Josep; Viñas Almenar, Inmaculada; Abadias i Sero, Mª Isabel; Torres Sanchis, Rosario
Pantoea agglomerans strain CPA-2 is an effective biocontrol agent (BCA) for postharvest diseases of citrus and pome fruits. However, for registration purposes and to implement their use as effective control strategy, it is necessary to study the traceability and survival of BCAs in their target application sites. The main objective of this work was to evaluate the persistence and quantify the population of CPA-2 after its postharvest application on orange cultivar 'Valencia Late' by molecular techniques. After application, the persistence of CPA-2 was evaluated by sampling the packing line and storage chambers, as well as on clothing of the workers by conventional PCR. The results showed that the maximum persistence of CPA-2 was lower than 3 days in surfaces of packing line. Furthermore, CPA-2 did not survive more than 1 day on working clothes, while in the environment or on different storage chamber surfaces it was not detected. In addition, the CPA-2 populations were quantified by quantitative PCR (qPCR) combined with a DNA intercalating reagent, propidium monoazide dye (qPCR-PMA) to quantify the CPA-2 viable cells on fruit surface. The qPCR-PMA method was compared with qPCR and dilution plating method. Results showed that CPA-2 populations quantiﬁed by qPCR-PMA were signiﬁcantly different compared with those obtained by qPCR during the time-course of the assay; however, no signiﬁcant differences were observed between qPCR-PMA and dilution plating. In conclusion, the persistence of CPA-2 was low at different sampling areas, suggesting that it cannot grow and survive on the surfaced sampled. Furthermore, qPCR-PMA method can be a quick and specific tool to monitor the viable population of CPA-2 on fruit surface.