Effect of ultrasound pre-treatment on the physical, microbiological, and antioxidant properties of calçots

The effect of ultrasound (US) treatment (40 kHz, 250 W) for 0, 10,25 and 45 min on the physical and microbiological quality, total antioxidant capacity (TAC) and total phenolic content (TPC) of calçots (Allium cepaL.) was evaluated. Moreover, the effect of roasting (270 °C, 8 min) and in vitro simulated digestion on the antioxidant properties was studied. Overall, US treatment had no effect of the physical quality and antioxidant properties of calçots regardless the treatment time, while thermal processing produced an increase on the TAC and maintenance in TPC. Furthermore, the digestion process caused a remarkable decrease on the TAC and TPC, but that decrease was higher in roasted than in fresh samples. The microbial load of all US-treated fresh samples was below 6 log (cfu g−1) and a decrease of 1-log reduction was observed after treating for 45 min. Those results indicated that US pre-treatment had no negative effects on the quality of calçot while produced a decrease on the microbial load at high processing times.This work was supported by ACCIÓ (Generalitat of Catalonia, RD14-1-004), Sociedad Agrícola i Secció de Crèdit de Valls S.C.C.L., Cooperativa of Cambrils, and PGI ‘Calçot de Valls’. This work was also supported by the ‘Secretaria d’Universitats i Recerca del Departament d’Economia i Coneixement’ (FI-2017-B2-00164, L. Zudaire) and CERCA Programme of Generalitat de Catalunya. T. Lafarga is in receipt of a ‘Juan de la Cierva’ contract awarded by the Spanish Ministry of Economy, Industry, and Competitiveness (FJCI-2016-29541). I. Aguiló-Aguayo thanks the National Programme for the promotion of talent and its employability of the ‘Ministerio de Economía,Industria y Competitividad’ of the Spanish Government and to the European Social Fund for the Postdoctoral Senior Grant ‘Ramon y Cajal’ (RYC-2016-19949)

Strategies to reduce microbial risk and improve quality of fresh and processed strawberries: A review

Strawberries are one of the most important fruits in the Mediterranean diet and have been widely investigatedfor their nutritional and nutraceutical properties. Concern about the safety of fresh and processed strawberrieshas increased in recent years due to the emergence of several outbreaks of foodborne pathogens linked to theirconsumption. The use of chlorine as a disinfectant has been identified as a concern due to public health issuesand limited efficacy at removing contamination, and preventing cross-contamination. This has led to the de-velopment of novel alternatives to chlorine disinfection and thermal treatments, which include, among others,the use of organic acids, high pressure processing, intense pulsed light, or pulsed electricfields. These tech-nologies do not generally affect the nutritional and organoleptic properties of the product and some of these havebeen reported to stimulate the production of valuable compounds in strawberries and to improve their overallquality.This work forms part of the FRESAFE Research Project (Mitigation Strategies to Reduce the Microbial Risks and Improve the Quality and Safety of Frozen and Ready-to-Eat Strawberries), funded by the Spanish Ministry of Economy, Industry and Competitiveness (AGL2016-78086-R). This work was also supported by the CERCA Programme of Generalitat de Catalunya. T. Lafarga is in receipt of Juan de la Cierva contract awarded by the Spanish Ministry of Economy, Industry, and Competitiveness (FJCI-2016-29541). I. Aguiló-Aguayo thanks the Spanish Ministry of Economy, Industry and Competitiveness and the European Social Fund for the Postdoctoral Senior Grant Ramon y Cajal (RYC-2016-19949)

Decontamination of Listeria innocua from fresh-cut broccoli using UV-C applied in water or peroxyacetic acid, and dry-pulsed light

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.This work has been supported by the CERCA Programme / Generalitat de Catalunya, the Secretaria d'Universitats i Recerca / Departament d'Economia i Coneixement / Generalitat de Catalunya, and the European Social Fund (grant FI-DGR-2015-0004); the University of Lleida (Ref.127/2016); the Spanish Ministry of Economy, Industry, and Competitiveness (grant FJCI-2016-29541); and the European Social Fund (grant RYC-2016-19949).The authors thank INRA (UMR SQPOV, Avignon), in particular Veronique Broussole and Fréderic Carlin, for providing access to the facilities. Thanks are also given to CLARANOR s.a. for allowing the use of the PL equipment, and in particular to Alain Berberian, for his technical assistance

Combination of sonication with anti-browning treatments as a strategy to increase the shelf life of fresh-cut potatoe (cv. Monalisa)

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.This work was financially supported by the Spanish “Ministerio de Educación, Economía y Competitividad” [Ramón y Cajal Program, RYC-2016-19949 (I. Aguiló-Aguayo), and Predoctoral grant, BES-2017-079779 (I. Nicolau-Lapeña)]. This work was supported by the CERCA Programme of Generalitat de Catalunya

An innovative water-assisted UV-C disinfection system to improve the safety of strawberries frozen under cryogenic conditions

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.FRESAFE AGL2016-78086-

Strawberry sanitization by peracetic acid washing and its effect on fruit quality

The risk posed by outbreaks associated with strawberries together with the safety issues of by-products from chlorine disinfection in the fruit industry has led to a search for alternative sanitizers. The disinfection capacity of peracetic acid (PA) at three concentrations (20, 40 and 80 ppm) and washing times (1 and 2 min) was compared to sodium hypochlorite (200 ppm) (NaClO) treatments and a water control, and its influence on the physico-chemical, biochemical and nutritional quality of strawberries was also studied. Counts on total aerobic mesophilic microorganisms were comparable between NaClO and PA. For yeasts and molds, only NaClO and 80 ppm PA reduced contamination in washing water, but no differences wereobserved in strawberries. Artificially inoculated L. innocua was reduced by at least 4 log cfu/g in strawberry by all the PA treatments, except at 20 ppm PA for 1 min. Total soluble solids, pH, titratable acidity, antioxidant activity and total phenolic content values were maintained after all treatments. Only anthocyanin content was affected. Treatments of 20 and 40 ppm PA did not significantly affect fruit color, and there were no losses on strawberry firmness. PA, as a GRAS substance that has shown potential to reduce microorganisms present in strawberries without any major physicochemical or sensorial alteration, could be a suitable alternative to chlorine disinfection.This work was financially supported by Spanish ‘Ministerio de Educación, Economía y Cultura’ [FRESAFE Project AGL 2016-78086-R, Ramón y Cajal Program, RYC-2016-19949 (I. Aguiló-Aguayo), Predoctoral grant, BES-2017-079779 (I. Nicolau-Lapeña) and Juan de la Cierva grant, FJCI-2016-29541 (T. Lafarga)]

Effect of thermosonication on the bioaccessibility of antioxidant compounds and the microbiological, physicochemical, and nutritional quality of an anthocyanin-enriched tomato juice

The aim of this study was to assess the potential of thermosonication as a strategy to obtain safe and high-quality tomato juice enriched in anthocyanins, formulated using strawberry processing co-products. Incorporation of strawberry press cake into the tomato juice resulted in higher polyphenolic and anthocyanin content and increased antioxidant capacity. Thermosonication for 5 min at 60 °C at either 35 or 130 kHz resulted in higher microbial inactivation when compared to thermal pasteurisation at 80 °C for 1 min. In addition, thermosonication allowed increased retention of colour attributes as well as polyphenol, lycopene, anthocyanin, and antioxidant capacity retention when compared to thermal treatment. For example, the total anthocyanin content decreased from 1.08 ± 0.04 mg/100 mL before processing to 0.92 ± 0.01 mg/100 mL after thermal pasteurisation but the difference was not significant when compared with the thermosonicated juice (1.06 ± 0.03 mg/100 mL). Although bioaccessibility of phenolic compounds after a simulated gastrointestinal digestion was lower in processed juices, thermosonicated samples showed a higher bioaccessibility when compared to the thermally treated ones.This work was supported by the CERCA Programme of Generalitat de Catalunya. T. Lafarga is in receipt of Juan de la Cierva contract awarded by the Spanish Ministry of Economy, Industry, and Competitiveness (FJCI-2016-29541). I. Aguiló-Aguayo thanks the Spanish Ministry of Economy, Industry, and Competitiveness and the European Social Fund for the Postdoctoral Senior Grant Ramon y Cajal (RYC-2016-19949)

Combination of ferulic acid with Aloe vera gel or alginate coatings for shelf-life prolongation of fresh-cut apples

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.The Agrimax project received funding from the Bio-based Industries Joint Undertaking under the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 720719. This work was also supported by the CERCA Programme of Generalitat de Catalunya. 720719. Nicolau-Lapeña is in receipt of a predoctoral grant awarded by the Spanish Ministry of Economy, Industry and Competitiveness (BES-2017-079779). Dr. I. Aguiló-Aguayo thanks the National Programme for the Promotion of Talent and Its Employability of the Spanish Ministry of Economy, Industry and Competitiveness, and the European Social Fund for her Postdoctoral Senior Grant ‘Ramon y Cajal’ (RYC-2016-2019 949)

Decontamination of fresh-cut broccoli with a water–assisted UV-C technology and its combination with peroxyacetic acid

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.This work has been supported by the CERCA Programme/Generalitat de Catalunya and by the Secretaria d’Universitats i Recerca del Departament d’Economia i Coneixement/ Generalitat de Catalunya (grant FI-DGR-2015-0004); by the Spanish Ministry of Economy, Industry, and Competitiveness (grant FJCI-2016-29541); and the European Social Fund (grant RYC-2016-19949). Thanks are also given to Ariadna Bademunt and Ismael Povedano for their technical assistance