Search

A case study of 15 wastewater treatment plants (WWTPs) at a full-scale was assessed for the risks of disinfection byproduct (DBP) formation, mainly the regulated trihalomethanes (THMs) and haloacetic acids (HAAs) and chlorate as an inorganic byproduct regulated recently in the EU. Raw wastewater from large, medium/small urban areas were treated with single or combined disinfection processes (i.e., chlorine, peracetic acid (PAA) and ultraviolet (UV) radiation). Sampling was executed once a month over seven months for the medium/small WWTPs and twice a month for the large ones. Due to the potential risk of SARS-CoV-2 contaminated wastewater, several inactivation methods were examined before the DBP analysis. Due to the inactivation step, the stability of THM4 and HAA9 suffered reductions, monitoring their presence only in the effluents after the disinfection treatments. In contrast, chlorate levels remained unchanged after the inactivation treatment; thus both raw wastewater and effluents were examined for their occurrence before disinfection treatments. Results showed that chlorate residues in the raw wastewater varied greatly from undetected levels to as high as 42.2 mg L−1. As the continuous monitoring of DBPs was performed, a positive correlation with chlorine or chlorine/UV was found. Changes in the physicochemical parameters indicated that the quality of the raw wastewater varied considerably depending on the WWTPs, and it influenced byproduct formation. In all WWTPs, chlorine alone or combined with UV significantly increased the presence of THMs, HAAs, and chlorate levels in the treated effluents. When the same WWTPs changed to PAA or PAA/UV, DBPs were diminished completely. This study highlights the risk of chlorate residues in raw wastewater during the pandemic. It also showed how the chemical risks of DBP formation could be reduced by changing the chlorinated disinfection technologies to PAA or PAA/UV, particularly if reclaimed water is intended for agricultural irrigation to minimize DBP residues., Authors are thankful for financial support from the Ministerio de Ciencia e Innovación (Project AGL 2016-75878-R). Sofía Albolafio benefitted from a grant (BES-2017-079969). Support provided by the Fundación Séneca (19900/GERM/15) was also appreciated

Sanitizers are an effective measure to maintain the microbiological safety of fresh produce process water. Proper water disinfection management is critical to avoid cross-contamination during the washing of fresh produce. Chlorine remains the most common sanitizer, and recent research deals, among other topics, with the comparison of different types of chlorine sources, optimization of doses for each product type and format, on-line monitoring systems, and mathematical modeling for process management. Peracetic acid (PAA) is the main industrial alternative but further research for the optimal dose and in-line monitoring and control systems is guaranteed. A plethora of other treatments are tested at a laboratory scale, but only a few are assessed under industrial conditions. Recent advances in the management of industrial fresh produce washing are presented and discussed., Authors are thankful for the financial support from the Ministerio de Ciencia e Innovacio´ [Project AGL2016-75878-R], the Center for Produce Safety, and CSIC [Intramural 201670E056]. Support provided by the Fundacio´n Se´neca [19900/GERM/15] is also appreciated

Fruit and vegetables contain a wide range of bioactive compounds or their precursors that provide health benefits such as reducing the risk of cardiovascular and chronic diseases. Fruit and vegetables can maintain their quality and extend the shelf life under storage at optimum temperature and relative humidity and adequate gas atmosphere composition (controlled atmosphere/modified atmosphere, CA/MA). The effect of CA/MA on bioactive compounds has not been extensively studied. The results vary among fruit species and cultivars, but the trend is for reduced O2 and/or elevated CO2 levels to enhance the retention of bioactive compounds. The reduction of temperature and of O2 concentration has been described as the two main factors contributing to preserve vitamin C. For carotenoids, the effect of CA/MA has not been well studied but, in general, it enhances the retention of carotenoids but also reduces their biosynthesis. Also phenolic biosynthesis may be negatively affected by high CO2 concentration, particularly anthocyanins in some fruits such as strawberries.

This chapter discusses requirements and recommendations for lettuce, escarole, and radicchio as when used as “whole head” at the final destination. The desired quality attributes and resistance or tolerance to handling-related injury depend on the maturity stage as it relates to size, firmness, and compactness. After harvest, these products should be cooled as soon as possible under vacuum cooling and hydrocooling for head and not-head types, respectively. Recommended storage conditions for low temperature (0°C) and high relative humidity (95%–100%) can be combined with CA (1%–3% O2 +

Fresh and fresh-cut vegetables are commercially stored without any control of light exposure. It is well known that light exposure prevents leaf senescence induced by darkness even at low temperature storage. This chapter reviews the influence of exposure to light conditions during storage on the impact of modified atmosphere (MA) that affects the quality characteristics of many fresh and fresh-cut vegetables. We included some experimental data of green and red baby leaf lettuce, fresh-cut iceberg lettuce, broccoli, and cauliflower florets stored under a light intensity of 20 μmol m− 2 s− 1, to show the significant differences in respiration rate and the MA generated inside the different packages. Under light conditions, respiratory activity was reduced in fresh-cut iceberg lettuce and broccoli florets and completely compensated in green and red baby leaf lettuce by photosynthesis, resulting in lower CO2 emission. The effect of light on respiration and transpiration rate must be taken into account for MA package design optimization in order to select the desired gas and water vapor transmission rate of the packaging materials.

Fresh-cut mushrooms can be stored for a limited time, but must be cooled quickly and be provided with an air gas composition with high relative humidity to maintain quality. For that reason, it is common to pack fresh-cut mushrooms in trays sealed with macroperforated film that allows water vapor exchange stored at low temperature (1–3°C). Since macroperforated films do not sustain modified O2 levels, they reduce the risk of Botulinum toxin production. An atmosphere of 3% O2 plus 10% CO2 can also maintain quality of fresh-cut mushroom slices when stored at 5°C. Storage with more than 20% CO2 accelerates tissue darkening, and

The main quality characteristics of fresh-cut potatoes that include a bright appearance, firm texture, and absence of darkening and dehydration can be maintained at low temperature (0°C) and high relative humidity (98%–100%). Ant browning agents such as sodium bisulfite combined with a low O2 level generated by modified atmosphere (MA) packaging with or vacuum packaging can prevent browning, which is the main cause of quality loss. Vacuum packaging is the most widely used method in the fresh-cut potato industry, but because of the potential risk of Clostridium botulinum growth, modified atmosphere (MA) packages can be used as an alternative although it is not as effective as vacuum packaging to control browning. For MA, as O2 concentration is not completely eliminated inside the package, it is necessary the combination of a chemical coadjutant to prevent browning and maintain other quality attributes such as texture. The best packaging method to preserve the sensory quality of fresh-cut potatoes up to 14 days at 4°C is vacuum or low O2 in combination with sodium bisulfite to avoid browning, but off-odors can be developed if storage temperatures are not well maintained (> 4°C) or the length of storage time is prolonged (> 8 days).

Fresh mature spinach leaves (Spinacia oleracea L.) of uniformly dark green color, crisp texture, and free from discoloration and decay achieve its maximum shelf life at low temperatures (0–5°C) and high relative humidity (90%–95% RH). In general, CA or MA is not used for the commercial storage of mature spinach leaves. Packaging typically involves the use of macroperforated film, which does not modify the gas composition for the prevention of water loss. MA is not used because CO2 levels must be controlled to less than

Fresh-cut lettuce is still the major fresh-cut product in the market since the early 90s. The main cause of quality loss after cutting is browning that occurs on the cut edge and causes visual rejection. Cut surface browning is particularly severe in some lettuce types such as romaine and iceberg. Browning of fresh-cut lettuce can be controlled using low temperatures (2°C), but if the storage temperature is not well maintained (> 2°C), use of packaging to establish a modified atmosphere (MA) of low O2 (1%) and moderate CO2 (5%–10%) can be successful in preventing browning. If the O2 level is too low (

Baby leaves have become increasingly popular as a ready-to-eat salad mix of different immature leaves with attractive colors and shapes that are flavorful and highly nutritious. Baby leaves can be washed and bagged as ready-to-eat salad or unwashed and packaged in trays to reduce physical damage and prevent water loss. Baby leaves should be stored at 0°C; this is the optimum temperature for a long shelf life. The storage life of the mix is dependent on the type of baby leaves included. Baby lettuce, for instance, can limit storage of a mix in that its quality is lower than other baby greens given the same storage time and temperature. For relative humidity, if baby leaves are unwashed they should be stored under high RH (95%–100%) to prevent water loss but if they are to be washed, a lower RH (70%–80%) is recommended as leaves can be rehydrated during washing. MA is mostly beneficial for controlling RH rather than atmosphere because the different species of baby leaves in the mix have differing recommendations for O2 and CO2 levels. Specific MA considerations for baby leaves including baby spinach, salad rocket, wild rocket, mizuna, watercress, and lamb lettuce are included. Problems under suboptimal conditions include the development of strong off-odors, decay, and yellowing.

9 páginas, 9 figuras, 1 tabla., Modified atmosphere packaging (MAP) has the potential to extend the shelf-life of fresh-cut lettuce mainly by limiting the oxidation processes. However, exposure to light conditions has been described as causing browning and quality loss. The influence of O2 partial pressures (pO2) and light exposure during storage on the shelf-life of fresh-cut Romaine lettuce was studied. Fresh-cut lettuce was exposed daily during storage to different light conditions: light (24 h), darkness (24 h) and photoperiod (12 h light + 12 h darkness). Changes in respiration rate, headspace gas composition, sensory quality, colour, electrolyte leakage, stomatal opening, water loss, texture and compositional constituents related to browning such as vitamin C and individual and total phenolic compounds were evaluated. Different weight samples (75–275 g), packaged with an initial pO2 of 0.5–2.0 kPa balanced with N2, reached pO2 from 0.1 to 1.5 at the steady-state. Atmospheres with low pO2 (0.2–0.5) at the steady-state preserved lettuce quality by the control of browning and the prevention of off-odours and off-flavours. Light exposure during storage positively influenced the number of open stomata (74% in light vs 24% in darkness) which contributed slightly to weight loss. Consumption of O2 in samples exposed to light differed significantly from those stored in photoperiod or darkness (10.6 ± 7.0, 18.3 ± 3.5 and 25.8 ± 8.6 nmol O2 kg−1 s−1, respectively). Packages exposed to light showed higher pO2 compared with packages stored in darkness while those exposed to photoperiod had intermediate values. Moreover, location of the packages in the shelves affected package headspace gas composition and thus, packages near the front of the shelves showed higher pO2 than those at the back. The different light conditions did not influence the content of vitamin C or the individual and total phenolic compounds. This study shows that under light conditions respiration activity was compensated by photosynthesis resulting in a higher pO2. Thus, browning of fresh-cut Romaine lettuce can be promoted by light exposure during storage as it increases headspace pO2., This work was supported by MICINN (project AGL2007- 65056) and European Community under FP7 (project VEG-i-TRADE 2010-244994). Consuelo Luna is supported by a grant (FPI, BES 2008 003768).

8 páginas, 6 figuras, 1 tabla., Aqueous chlorine dioxide (ClO2) has been postulated as an alternative to sodium hypochlorite (NaClO) for fresh-cut produce sanitization with the advantage of avoiding the risks associated with chlorination by-products. However, little is known about its influence on preserving quality and the potential formation of trihalomethanes (THMs) under typical processing conditions. The suitability of aqueous chlorine dioxide (3 mg L−1) as an effective sanitizer of fresh-cut iceberg lettuce stored under active modified atmosphere packaging (MAP) at refrigerated conditions was determined and compared with sodium hypochlorite (100 mg L−1). Fresh-cut lettuce washed with tap water was used as a control. The epiphytic microbiota were characterized by the evaluation of the major relevant microbial groups such as mesophiles, psychrophiles, Pseudomonas spp., Enterobacteriaceae, lactic acid bacteria, yeasts and moulds. Additionally, gas composition, sensory quality, vitamin C and individual and total phenolics were monitored after washing and during storage for 3 d at 4 °C followed by 7 d at 8 °C. In general, the natural microbiota of fresh-cut lettuce after washing and storage was equally affected by the different washing solutions, with the exception of yeasts which showed the highest growth after 10 d storage in samples washed with chlorine dioxide. None of the tested washings negatively affected sensory quality, which was acceptable after 10 d storage. Additionally, the content of bioactive compounds was not significantly affected either by washing solution or by storage time. The potential formation of THMs was evaluated by the analysis of lettuce washed in water with a chemical oxygen demand (COD) of 700 mg L−1 treated for 30 min with sodium hypochlorite (100 mg L−1) or chlorine dioxide (3.7 mg L−1). Trihalomethane formation was only detected in the process water in which sodium hypochlorite was applied (217 ± 38 μg L−1). However, THMs formation in fresh-cut lettuce was negligible despite the sanitation procedure. The formation of THMs was only detected in fresh-cut lettuce when sodium hypochlorite was used under very extreme conditions where lettuce was washed in water with a high level of organic matter (COD = 1800 mg L−1), high sodium hypochlorite concentration (700 mg L−1) and long contact time (60 min). Our data suggest that aqueous chlorine dioxide is as suitable as sodium hypochlorite for fresh-cut lettuce sanitation with the advantage of preventing the formation of THMs., The authors are grateful to CICYT (project AGL2007-65056) for financial support. Maria V. Selma and Francisco López-Gálvez are holder grants founded by CSIC (I3PDR-7-01 contract and I3P grant). Ana Allende was the recipient of a Ramon y Cajal Contract from the Spanish Ministry of Science and Research and Pilar Truchado holds a PhD grant from the Seneca Foundation (Murcia, Spain).

6 páginas, 4 figuras., Chlorine dioxide (ClO2) has been postulated as an alternative to sodium hypochlorite (NaClO) for fresh-cut produce sanitization to avoid risks associated with chlorination by-products. Experiments were performed to determine the prevention of cross-contamination of fresh-cut lettuce by Escherichia coli using chlorine dioxide (3 mg/L) or sodium hypochlorite (100 mg/L) as sanitation agents. The efficacy of these sanitation solutions was evaluated simulating as much as possible the conditions of a fresh-cut processing line. Thus, to evaluate the potential risk of cross-contamination during pre-washing, inoculated fresh-cut lettuce was pre-washed and after that non-inoculated lettuce was then pre-washed in the same water. After this pre-washing, non-inoculated lettuce was cross-contaminated, changing from 0 to 3.4 log units of E. coli cells. During washing with sanitizers, none of the tested sanitation agents significantly reduced E. coli counts in both inoculated and cross-contaminated lettuce. These results suggest that when cross-contamination occurs, even if the event is recent, subsequent sanitation steps are inefficient for inactivating E. coli cells on the vegetable tissue. However, chlorine dioxide and sodium hypochlorite solutions were able to inactivate most E. coli cells that passed from inoculated product to wash water. Therefore, they might be able to avoid cross-contamination between clean and contaminated product during the washing step. Scanning electron microscopy micrographs indicated that bacterial cells were mainly located in clusters or tissue stomata where they might be protected, which explains the low efficacy of sodium hypochlorite and chlorine dioxide solutions observed in this study., The authors are grateful to CICYT (project AGL2007-65056) for financial support. Maria V. Selma and Francisco López-Gálvez are holder grants founded by CSIC (I3PDR-7-01 contract and I3P grant). Ana Allende was the recipient of a Ramon y Cajal Contract from the Spanish Ministry of Science.

5 páginas, 3 figuras, 2 tablas.-- El PDF es la copia de autor., The efficacy of fresh-cut produce sanitizers has mainly been evaluated by measuring microbial reductions on produce. However, its suitability to ensure that pathogens are rapidly killed avoiding cross-contamination of subsequent product also needs to be considered. The efficacy of chlorine, Tsunami®, Citrox® and Purac® on non pathogenic Escherichia coli reductions in processing water and on fresh-cut lettuce were studied. Selection of minimum effective doses was carried out in processing water, which contained a chemical oxygen demand (COD) within the range of 700–1000 mg/l and a total mesophilic load of about 7 log CFU/ml. The processing water was inoculated with two inoculum levels (3 and 5 log CFU/ml). It was observed that 40 mg/l of chlorine and 500 mg/l of Tsunami were effective in reducing the inoculum levels in the processing water to the detection limit (5 and 4 log units). However, Citrox and Purac were not effective in reducing E. coli population even at the highest manufacturer's recommended doses. Evaluation of cross-contamination in fresh-cut lettuce was carried out by measuring E. coli transfer from inoculated (~ 5 log CFU/g) to uninoculated lettuce after washing the contaminated product in the water containing different sanitizing agents. Chlorine and Tsunami were able to inactivate E. coli in wash water, avoiding cross-contamination between contaminated and non-contaminated product. However, Citrox and Purac at the recommended doses did not prevent transfer of E. coli cells between inoculated and uninoculated fresh-cut lettuce and therefore indicating cross-contamination. The results obtained show that chlorine and Tsunami are recommended as water disinfection agents preventing E. coli cross-contamination of produce during processing., The authors are grateful to CICYT (project AGL2007-65056) for financial support. A. Allende,M.V. Selma and F. López-Gálvez are holder grants founded by CSIC (E-30-2008-0220871, I3PDR-7-01 contracts and I3P grant).

8 páginas, 3 figuras, 6 tablas., Quorum sensing (QS) inhibitory activity of 29 unifloral honeys was evaluated using the bacterial model Cromobacterium violaceum. The tested honeys were able to inhibit the production of acyl-homoserine lactones (AHLs) produced by C. violaceum at 0.1 g/ml. However, chestnut and linden honey samples showed the highest inhibitory activity, while orange and rosemary were less effective in inhibiting QS. When honey samples from the same floral origin obtained from different geographical regions were compared, they showed similar QS inhibitory activity. Thus, one of the factors which influence the inhibitory activity could be derived from the floral origin, independently of the geographic location. It was observed that unifloral honey samples showed “non-peroxide” anti-QS activity, which was not linearly correlated with total and individual phenolic compounds. The obtained results showed that the preservative properties of honey could be due to both the antimicrobial properties and the QS inhibitory capacity., Support of the EU-Funded Project ‘‘Bees in Europe and Sustainable Honey Production” (‘‘BEE SHOP”, Ref: FOOD 2006-022568- BEESHOP) is gratefully acknowledged. A. Allende and F. López-Gálvez hold grants founded by CSIC (JaeDoc- 2007 and I3P contracts) and P. Truchado holds a PhD grant from the Seneca Fundation (Murcia, Spain).

7 páginas, 6 figuras, 1 tabla., Carrot sticks are increasingly in demand as ready-to-eat products, with a major quality problem in the development of white discoloration. Modified atmosphere packaging (MAP) and edible coating have been proposed as postharvest treatments to maintain quality and prolong shelf-life. The combined application of an edible coating containing 5 mL L−1 of chitosan under two different MAP conditions (10 kPa O2 + 10 kPa CO2 in Pack A and 2 kPa O2 + 15–25 kPa CO2 in Pack B) over 12 d at 4 °C was studied. Respiration rate, microbial and sensory qualities as well as the contents of vitamin C, carotenoids and phenolics of coated and uncoated carrot sticks were evaluated. The use of the edible coating containing chitosan preserved the overall visual quality and reduced surface whiteness during storage. Microbial populations were very low and not influenced by coating or MAP. Edible coating increased respiration rates of carrot sticks, although this was only noticeable in the package with the less permeable film (Pack B). Vitamin C and carotenoids decreased during storage particularly in coated carrot sticks. In contrast, the content of total phenolics markedly increased in coated carrot sticks stored under moderate O2 and CO2 levels, while it was controlled under low O2 and high CO2 levels. The combined application of edible coating containing chitosan and moderate O2 and CO2 levels maintained quality and enhanced phenolic content in carrot sticks., The authors are grateful to CICYT (project AGL2007-65056), CNPq, PRODETAB and FAPEMIG for financial support and Agricola Villena for providing plant material. A. Allende is holder a contract founded by CSIC (E-30-2008-0220871).

The flow of air to feed oxygen to the cathode of each plate in a proton exchange membrane fuel cell (PEMFC) is studied for a 300 W stack in a realistic 3D configuration. Two configurations for gas income are solved, a "U" shape, where both the inlet and outlet of the air collectors are at the same end plate, and a "Z" shape, where inlet and outlet are at opposite sides of the stack. Under a simplified assumption for the flow of oxygen entering the gas diffusion layer of each cell, detailed mass flow and pressure distributions are shown, including the possibility of a turbulent flow inside the main collectors. © 2008 Elsevier B.V. All rights reserved.

9 pages, 5 figures, 5 tables., Increasing concerns about the possible formation of carcinogenic compounds and the emergence of new, more tolerant pathogens, have raised questions on the use of chlorine in fresh-cut produce. There is a growing need to investigate the efficacy of new commercial sanitizing and other alternative technologies. In the present study, the effectiveness of chlorine and other commercial sanitizer agents (Sanova, Sanoxol 20, Tsunami 100, Purac FCC 80, Citrox 14W and Catallix) was evaluated on epiphytic microorganisms and their influence on the sensory quality of fresh-cut escarole and lettuce. Different sanitizer concentrations (manufacturer's recommended dose and half of this dose) and application systems (submersion and spray) were also compared. The antimicrobial efficacy of the treatments was evaluated, initially after washing, and after 8 days of storage simulating a commercial shelf-life (3 days at 4 °C + 5 days at 8 °C). All the tested washing solutions were more effective in reducing the microbial load than water washes, particularly in fresh-cut escarole. However, the microbial load of fresh-cut escarole and lettuce after 8 days of storage was very similar for most of the treatments despite the different application systems and concentrations of the sanitizers. Clearly epiphytic microorganisms of fresh-cut escarole and lettuce were able to grow rapidly during storage under low temperature, reaching similar or higher values than the unwashed fresh-cut produce at the day of production. The overall visual quality of fresh-cut salad leaves was scored as good or very good (≥6) after 8 days of storage, except for the product washed with Purac. Thus, despite the high number of mesophilic bacteria present in the product, between 6 and 8 log cfu g−1, it was not associated with a detrimental quality. Therefore, the determination of the initial epiphytic reductions of fresh-cut products after washing with different sanitizing agents provides little information about the microbial or sensory quality of the product at the time of consumption., The authors are grateful to CICYT (project AGL2004-03060) for financial support. A. Allende is indebted to the MEC (Juan de la Cierva contract, JCI-2004-000718) and M.V. Selma to CSIC (I3P contract, I3PDR-7-01).

8 pages, 4 tables, 3 figures., Several outbreaks of shigellosis have been attributed to the consumption of contaminated fresh-cut vegetables. The minimal processing of these products make it difficult to ensure that fresh produce is safe for consumer. Chlorine-based agents have been often used to sanitize produce and reduce microbial populations in water applied during processing operations. However, the limited efficacy of chlorine-based agents and the production of chlorinated organic compounds with potential carcinogenic action have created the need to investigate the effectiveness of new decontamination techniques. In this study, the ability of ozone to inactivate S. sonnei inoculated on shredded lettuce and in water was evaluated. Furthermore, several disinfection kinetic models were considered to predict S. sonnei inactivation with ozone. Treatments with ozone (1.6 and 2.2 ppm) for 1 min decreased S. sonnei population in water by 3.7 and 5.6 log cfu mL−1, respectively. Additionally, it was found that S. sonnei growth in nutrient broth was affected by ozone treatments. After 5.4 ppm s ozone dose, lag-phases were longer for injured cells recovered at 10 °C than 37 °C. Furthermore, treated cells recovered in nutrient broth at 10 °C were unable to grow after 16.5 ppm s ozone dose. Finally, after 5 min, S. sonnei counts were reduced by 0.9 and 1.4 log units in those shredded lettuce samples washed with 2 ppm of ozonated water with or without UV-C activation, respectively. In addition, S. sonnei counts were reduced by 1.8 log units in lettuce treated with 5 ppm for 5 min. Therefore, ozone can be an alternative treatment to chlorine for disinfection of wash water and for reduction of microbial population on fresh produce due to it decomposes to nontoxic products., The authors are grateful to Spanish CICYT (Comisión Interministerial de Ciencia y Tecnología) project AGL2004-03060 for financial support. D. Beltrán is holder of a grant from Ministerio de Ciencia y Tecnología (Spain) reference BES-2002-0216.

11 pages, 7 figures., Modified atmosphere packaging (MAP), ozone (O3) and ultraviolet-C (UV-C) light, have been suggested as postharvest treatments to control decay of strawberries. However, the influence of these treatments on strawberry phytochemicals has not been thoroughly evaluated. Thus, the impact of individual and combined UV-C light (1 kJ m−2), gaseous O3 (5000 mg L−1) and two active MAP conditions (superatmospheric O2 and CO2-enriched atmospheres) on the polyphenols, vitamin C content and shelf-life of strawberries was studied. Samples were taken initially, and after 5, 9 and 12 days of storage and microbial, nutritional and organoleptical qualities were evaluated. None of the evaluated samples showed visual signs of fungal growth after 12 days of storage, including non-treated samples stored in air. However, phenolic contents of UV-C and O3 treated strawberries were significantly reduced after treatments, mainly due to a significant decrease in procyanidins. Ozonated samples showed the lowest vitamin C contents at the end of storage. On the other hand, when compared with storage in air, strawberries stored under superatmospheric O2 and CO2-enriched concentrations showed lower total phenolic contents after 5 days and a vitamin C reduction after 12 days of storage, accompanied by a more pronounced conversion from reduced to oxidized forms under superatmospheric O2. In general, overall quality was good in all samples throughout the shelf-life except for flavour scores of MAP strawberries, which were clearly lower than air-stored samples after 9 and 12 days of storage. No additional effect was observed when combining the postharvest treatments compared with the effect of individual treatments., The authors are grateful to European Commission FLAVO (Flavonoids in fruits and vegetables: their impact on food quality, nutrition and human health) and project AGL2004-03060 for financial support. A. Allende is indebted to the Ministerio de Educacion y Ciencia for a Juan de la Cierva contract (JCI-2004-000718).

8 pages, 4 atbles, 3 figures., The fresh-cut fruit and vegetable industry is searching for alternatives to replace chemical treatments with biopreservative approaches that ensure the safety of the product and fulfil consumer preferences for minimally processed foods. In this study, the use of bacteriocins produced by lactic acid bacteria has been tested as a substitute for chemical disinfection of fresh-cut iceberg lettuce. First, the ability of several non-plant origin bacteriocinogenic strains (nisin Z+, plantaricin C+, lacticin 481+, coagulin+ or pediocin PA-1+) to grow in a lettuce extract at 4 °C, 10 °C and 32 °C was tested. All strains were able to grow, but bacteriocin production was predominantly detected at 32 °C. Addition of bacteriocinogenic supernatants (nisin+, coagulin+ and a nisin–coagulin+ cocktail) to tryptic-soy agar plates inoculated with Listeria monocytogenes reduced Listeria counts by approximately 1–1.5 log units compared with the control plates without bacteriocin, after 48 h of storage at 4 °C. The effect of washing with bacteriocin-containing solutions on survival and proliferation of Listeria monocytogenes was also evaluated in fresh-cut lettuce packaged in macro-perforated polypropylene bags and stored for 7 days at 4 °C. Washing fresh-cut lettuce with these solutions decreased the viability of Listeria monocytogenes by 1.2–1.6 log units immediately after treatment, but, during storage at 4 °C, bacteriocin treatments only exerted minimal control over the growth of the pathogen. Natural microbiota were little affected by bacteriocins during storage., This work was funded by the Spanish Ministerio de Educación y Ciencia (Project AGL2003-06440-CO2-01). A. Allende is the recipient of a Juan de la Cierva Contract (CI-2004-000718).

12 pages, 3 tables, 6 figures.-- Available online 7 Sept 2006., Leafy salad species are increasingly consumed in the human diet and there is increased concern about the levels of microbial organisms in these raw foods, and especially bacteria such as Salmonella that cause food poisoning. Various chemical sanitizers therefore are used to control microorganisms and fungi, but there is very little information on the effects of these chemicals on food composition. Wild rocket (Diplotaxis tenuifolia L. DC) leaves were washed using tap water, chlorine (100 mg L−1), ozonated water (10 mg L−1), lactic acid (Purac® 20 mL L−1), acidified sodium chlorite (Sanova® 250 mg L−1) and peroxyacetic acid (Tsunami® 300 mg L−1). The effects of sanitizers on the contents of Vitamin C, polyphenols and glucosinolates of rocket leaves were studied under air and low O2 (1–3 kPa) + high CO2 (11–13 kPa) for 15 days at 4 °C. All the sanitizers effectively reduced microbial growth on the day of processing, but only Purac, Tsunami and Sanova inhibited the microbial growth throughout the shelf life. The visual quality was acceptable for all treatments in air while it was poor under low O2 + high CO2. In addition, Purac was particularly detrimental for sensory quality. Both chlorophyll a and chlorophyll b contents were reduced throughout storage but were independent of washing treatments and storage conditions. The content of vitamin C was maintained for up to 8 days of storage under air and low O2 + high CO2, but Purac washes markedly reduced the vitamin C content. A clear decrease in ascorbic acid followed by an increase in dehydroascorbic acid was observed when samples were stored under low O2 + high CO2. The content of flavonoids was not affected by the washing solutions on the processing day and remained almost constant throughout the storage in air. However, marked reductions were observed when samples were stored under low O2 + high CO2. The glucosinolates were the most affected constituents of rocket leaves as the content was reduced from 4 to 33% when samples were stored in air while the decrease was between 60 and 100% in low O2 + high CO2. These data revealed that Sanova and Tsunami could be alternative sanitizers to chlorine for rocket leaf washes due to good retention of sensory quality with no detrimental reduction of the antioxidant constituents., The authors are grateful to Spanish CICYT (Comisión Interministerial de Ciencia y Tecnología) project AGL2004-03060 for financial support and Agrolito for supplying plant material. A. Martínez-Sánchez is indebted to the Ministerio de Educacion y Ciencia for a FPU grant (AP2003-3990). R.N. Bennett is funded by the Portuguese Foundation of Science and Technology.

7 pages.-- Available online 12 June 2006.-- Innovations in Traditional Foods, EFFoST 2005 conference., The industry of fresh-cut fruits and vegetables is constantly growing due to consumers demand. New techniques for maintaining quality and inhibiting undesired microbial growth are demanded in all the steps of the production and distribution chain. In this review, we summarize some of the new processing and preservation techniques that are available in the fresh-cut industry. The combination of sanitizers with other intervention methods is discussed. The use of ultraviolet-C, modified-atmospheres, heat shocks and ozone treatments, alone or in different combinations have proved useful in controlling microbial growth and maintaining quality during storage of fresh-cut produce. In addition, combinations of physical and chemical treatments are also reviewed. The use of acidic or alkaline electrolyzed water (AcEW), chlorine dioxide, power ultrasound and bacteriocins and the potential applications to the fresh-cut products industry to control human microbial pathogens are presented., The authors are grateful to Spanish CICYT (Ministerio de Educación y Ciencia) project AGL2004-03060 for financial support.

10 pages, 1 table, 3 figures., Chemicals containing SH-groups as sulfites and chlorine-based agents are commonly employed in the fresh-cut process of vegetables such as potatoes to prevent browning and to sanitize produce. However, there is a concern over the application of these compounds in fresh-cut commodities as they might affect human and environmental safety and this has created the need to investigate alternatives. In the present work, the effectiveness of different traditional and non-traditional sanitizers on the sensory and microbial quality of fresh-cut potatoes stored under passive modified atmosphere packaging (MAP) and vacuum packaging was investigated. Six different washing treatments consisting of water, sodium sulfite, sodium hypochlorite, Tsunami, ozone and the combination of ozone–Tsunami were evaluated. Browning and growth of aerobic mesophilic bacteria, psychrotrophic bacteria, coliforms, lactic acid bacteria (LAB), anaerobic bacteria, moulds and yeasts were studied. In general, vacuum packaging preserved the appearance better than MAP. Under MAP only sodium sulfite prevented browning although it conferred off-odors. After 14 days of storage, there was no evidence of browning in fresh-cut potatoes dipped in ozonated water or ozone–Tsunami and stored under vacuum and these treatments maintained initial texture and aroma. However, the use of ozonated water alone was not effective in reducing total microbial populations. Ozone–Tsunami resulted in the most effective treatment to control microbial growth achieving 3.3, 3.0 and 1.2 log-reductions for LAB, coliforms and anaerobic bacteria, respectively. Therefore, although microbial growth was not slowed down by ozone alone, the combination of ozone–Tsunami resulted an efficient and promising treatment for controlling microbial growth and maintaining sensory quality of potato strips under vacuum., The authors are grateful to Spanish CICYT (Comisión Interministerial de Ciencia y Tecnología) Projects AGL2000-0452-P4-03 and AGL2001-1269 for financial support. D.B. is holder of a grant from Ministerio de Ciencia y Tecnología (Spain), reference BES-2002-0216. J.A.T. has a fellowship from Ministerio de Educación, Cultura y Deporte (Spain), reference AP2001-2493.

11 pages, 7 tables, 3 figures., Quality of Pleurotus ostreatus mushrooms was compared during cold storage under various temperatures and modified atmospheres with and without moisture absorbers. CO2 production followed a non-climacteric pattern and was about 0.50, 0.99 and 1.23 μmol CO2 kg−1 s−1 at 0, 4 and 7 °C, respectively, after 12 h. At the end of 11 days of storage, the respiration rates were very similar for all the assayed temperatures (±0.37 μmol CO2 kg−1 s−1). The best mushroom appearance was found at 0 °C, although for optimizing modified atmosphere packaging (MAP), 4 °C was selected to minimize low-temperature damage. When prolonging the storage beyond 7 days, quality characteristics dropped sharply and the mushrooms were not marketable, except when kept at 0 °C. Therefore, 7 days was the maximum recommended storage period for Pleurotus mushrooms. MAP at 4 °C for 7 days was created using microperforated polypropylenes (MPP1 and MPP2), low-density polyethylene (LDPE) and polyvinyl chloride (PVC) films. Results were compared with macroperforated polypropylene (PP) control packages. In order to avoid condensation, sorbitol and silica gel were used to modify the in-package relative humidity. Moisture absorbers did not modify the gas composition of the packages. Sorbitol promoted tissue leakage and cannot be recommended. Lower relative humidity was observed in packages containing silica gel and this did not affect the quality of the mushrooms. However, increasing amounts of silica gel increased weight loss in Pleurotus mushrooms, and high weight loss detected in PP packages made these unacceptable. MAP (15 kPa O2+5 kPa CO2) was found beneficial for maintaining acceptable quality of Pleurotus for 7 days at 4 °C., The authors are grateful to UE, Project EUCRAFT QLK5-CT-1999-70010 for financial support.

10 pages, 4 figures., The effect of cutting and storage in air (AIR), modified atmosphere packaging (MAP) and deep-freezing (DF) on the vitamin C content of potato strips was evaluated. The -ascorbic acid (AA) content of potato strips derived from five potato cultivars (‘Agria’, ‘Cara’, ‘Liseta’, ‘Monalisa’ and ‘Spunta’) previously held in long-term storage was determined. In a second experiment, new-season potato tubers of ‘Agria’ and ‘Spunta’ cvs were used. Fresh-cut potato strips were stored for 6 days at 4 °C while DF strips were evaluated up to 5 weeks upon storage at −22 °C. All fresh-cut samples stored in AIR showed an increase in AA content (16–108%) after 2–4 days at 4 °C. At the end of storage, all fresh-cut potatoes stored in AIR had AA contents at or above initial concentrations, except new-season ‘Spunta’ tubers which experienced a 26% decrease. Moreover, potato strips from new-season ‘Agria’ tubers increased in vitamin C content after 6 days by 12%. Steady state MAP conditions were reached after 2 days with concentrations of 8.2–9.8 kPa CO2 and 3.1–3.8 kPa O2 within the packages. Potato strips stored in MAP decreased in AA content by 14–34% compared to samples held in AIR. Frozen storage resulted in a reduced vitamin C content (23%) of ‘Spunta’ potato strips after 5 weeks while ‘Agria’ tubers did not show any change. A general increase over time in the respiration rate of potato strips was observed during storage at 4 °C. As a conclusion, vitamin C content of fresh-cut potatoes was retained in AIR storage after 6 days at 4 °C while it was reduced in MAP storage and frozen storage at −22 °C., The authors are grateful to Spanish CICYT, Project AGL2001-1269 for financial support. J.A. Tudela was supported by a grant from Consejo Superior de Investigaciones Científicas (CSIC).

4 pages, 3 figures., The effect of temperatures (0, 2, 5, 7 and 10°C) for 14 days of storage on antioxidant constituents such as vitamin C and phenolic compounds of artichoke c.v. ‘Blanca de Tudela’ was studied. Three groups of phenolics were identified and quantified as: chlorogenic acid; 1,5-dicaffeoylquinic acid (1,5 di-CQA)+3,5-dicaffeoylquinic acid (3,5 di-CQA); and 1,4-dicaffeoylquinic acid (1,4-di-CQA)+4,5-dicaffeoylquinic acid (4,5 di-CQA). The content of vitamin C was higher in the internal bracts compared with the external ones (144 and 193 mg kg−1 fresh wt., respectively) and decreased after 14 days of storage under the assayed temperatures. Each individual group of phenolics was 10-fold higher in the internal bracts than in the external ones. At harvest, total phenolics (618 mg kg−1), chlorogenic acid (143 mg kg−1) and 1,4 di-CQA+4,5 di-CQA (207 mg kg−1), increased in internal bracts after storage, particularly at 2, 5 and 7°C. On the other hand, 1,5-di-CQA+3,5-di-CQA decreased from 260 to 150 mg kg−1 after storage. Consumption of the edible artichoke fraction could be an important source of natural antioxidants and provide significant nutritional value to the diet., The authors are grateful to the Spanish CICYT for their financial support of this work ŽALI98-0843, 95-0297-OP. AGI thanks the Spanish MEC for their pre-doctoral grant.

Flavonoids and other phenolic metabolites have important biological activities related to their antioxidant properties and, especially, to their free-radical scavenging ability. It has been suggested that dietary phenolics might be beneficial agents for the prevention of cardiovascular diseases and cancer, a suggestion supported by epidemiological and experimental studies. In the present review, the antioxidant activity of flavonoids and other phenolic metabolites is reviewed, as well as their bioavailability, absorption and metabolism in animals and humans. In addition, the flavonoid content and that of other phenolics in different fruits and vegetables is reviewed. The changes in flavonoids and other phenolic antioxidants during the postharvest life of fruit and vegetables are evaluated. The effect of storage, technological treatments (controlled atmospheres, UV irradiation, heat shocks, etc.), and processing (minimal processing, juice manufacturing, drying, cooking, canning, etc.) on the content of the biologically active phenolics is also reviewed.