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- Relationship between postharvest diseases resistance and mineral composition of citrus fruitPublication . Nunes, C.; Duarte, Amílcar; Manso, T.; Weiland, C.; Garcia, J. M.; Cayuela, J. A.; Yousfi, K.; Martínez, M.C.; Salazar, Miguelreen and blue moulds, due to the pathogenic action of Penicillium digitatum and Penicillium italicum respectively are the main cause of orange losses during postharvest. Under Mediterranean climate conditions, both together are responsible for 80% of total postharvest citrus fruit decay. The type of orchard production system, field location with different types of climate and soil has a main influence on mineral composition of fruits. The mineral composition of fruits can have a significant impact on fruit quality and shelf life during postharvest period. These include effects on fruit colour, texture, disease susceptibility, juice composition and development of physiological disorders. Oranges from different regions from South of Spain and Portugal and from three different production systems (conventional, integrated and organic) were studied to evaluate whether both factors (origin and production system) affected the degree of fruit sensitivity to decay. Results indicate that the sensitivity to green or blue mould is determined better by the origin of fruit than by the system of production.
- Effect of electrolyzed water as a disinfectant for fresh-cut fruitPublication . Graça, Ana; Salazar, Miguel; Quintas, Célia; Manso, Teresa; Nunes, Carla; Nunes, CarlaIn fresh-cut processing the disinfection is the most important step. This process can affect the quality and the safety of the end product as well as its shelf life. Chlorine is the most used disinfectant in fresh-cut industry but due to its association with environmental and health risks, the development of alternative sanitizers is emergent. Electrolyzed water (EW) may be an alternative to the use of chlorine sanitizers and both acidic electrolyzed water (AEW) and neutral electrolyzed water (NEW) can be used with this purpose. In fact, several studies have shown that EW can be effective in reducing pathogenic bacteria on the surface of fruits and vegetables. This manuscript presents a review of electrolyzed water approaches, its antimicrobial activity in fresh-cut produce and the results of a study undertaken in our laboratory to evaluate the disinfection efficacy of AEW and NEW on fresh-cut apples and oranges. Fresh-cut apples and fresh cut oranges were inoculated with a suspension of Listeria innocua and fresh-cut oranges with Escherichia coli at a concentration of 107 cfu mL-1 and treated with the different solutions. Untreated freshcut fruits were used as control. The best sanitizing treatment for both pathogens and fruits was AEW at 200 ppm of free chlorine applied during 5 minutes.
- Efficacy of electrolyzed water to inactivate foodborne pathogens on fresh-cut applesPublication . Graça, Ana; Nunes, C.; Quintas, Célia; Abadias, Maribel; Usall, J.; Salazar, MiguelChlorine is the most common disinfectant used in the fresh-cut industry but nowadays environmental and health risks have led to the need to find new sanitizers. Electrolyzed water (EW) appears to be a promising alternative. In this work, disinfection efficacy of acidic (AEW) and neutral (NEW) electrolyzed water in fresh-cut apple slices inoculated with Escherichia coli, Listeria innocua or Salmonella choleraesuis was studied. Apple slices were inoculated with a 10(7) cfu/ml suspension of pathogens and treated with the sanitizer EW solutions, with 100 or 50 ppm of free chlorine solutions and with distilled water. Population reduction was determined 30 min after washings and untreated apple slices were used as control in all assays. AEW100 was the treatment with more effective bactericidal activity followed by NEW100 and AEW50. EW had higher or similar efficacy than chlorine treatments in all tested conditions.
- Low dose UV-C illumination as an eco-innovative disinfection system on minimally processed applesPublication . Graça, Ana; Salazar, Miguel; Quintas, Célia; Nunes, C.In this study, the efficacy of UV-C illumination for inactivate Escherichia coli, Listeria innocua or Salmonella enterica, individually or in a mixture, in vitro and on apple slices was determined. Apple slices inoculated with a 10(7) cfu/mL suspension of above indicated pathogens were irradiated on both sides with UV-C illumination, with doses of 0.5 and 1.0 kJ/m(2). UV-C illumination disinfection efficacy was compared to that of washings with sodium hypochlorite at 100 ppm of free chlorine and with distilled water. Bactericidal activity of each treatment was assessed after 30 min and after 7 and 15 days of storage at 4 degrees C. Results showed that UV-C illumination at 1.0 kJ/m(2) could be an alternative to the wash with hypochlorite solutions. On the in vitro study, these doses completely inhibited the growth of the three bacteria either as pure cultures or in a mixture. In fresh-cut apple, the pathogens were also affected by the UV-C illumination, the 1.0 kJ/m(2) dosage being the one that resulted in higher bacteria inhibition in almost every case. The UV-C treatment did not affect the quality properties of fresh-cut apple. 2013 Elsevier B.V. All rights reserved.
- Métodos eco-inovadores de desinfecção para fruta cortada de modo de produção biológicoPublication . Duarte, Amílcar; Graça, Ana; Salazar, Miguel; Nunes, CarlaO cloro é o desinfectante de uso habitual a indústria de fruta cortada mas apresenta problemas de eficácia, de saúde e ambientais, pelo que há uma tendência para ser eliminado do processo de desinfecção, não apenas para os alimentos de modo de produção biológico (MPB) mas também de alimentos convencionais. Neste trabalho foi testada em pêra 'Rocha'cortada a actividade biocida de três sistemas eco-inovadores de desinfecção (iluminação UV-C, água electrolisada e água ozonizada). Cubos de pêra foram inoculadas com uma suspensão de Escherichia coli, Listeria innocua ou Salmonella choleraesuis e tratados com os sistemas eco-inovadores. Para cada um testaram-se diferentes doses ou tempos de exposição (UV-C: 0-10 kJ.m-2 ; água electrolisada: 10-200 ppm cloro livre, 5 min; e água ozonizada: 0,4 ppm, 1-5 min). Como testemunha utilizou-se o tratamento com hipoclorito de sódio a 100 ppm. Os resultados demonstram que o sistema mais eficaz foi a iluminação UV-C, seguido de água electrolisada e de água ozonizada. A iluminação UV-C e a água electrolisada apresentaram, de um modo geral, eficácia superior à do hipoclorito de sódio e o ozono, eficácia similar. Dos métodos testados, o mais promissor para uso em alimentos MPB e numa agricultura sustentável é a iluminação UV-C, pois, além de elevada eficácia, apresenta a vantagem de não utilizar água nem produzir resíduos nem subprodutos nos frutos nem no ambiente.