Quantification of postharvest diseases of guava accessions cultivated in organic system

Among the postharvest diseases that occur in guava, anthracnose, black spot and stem-end rot are the most common. The incidence and diversity of these diseases depend on the host genotype. This study aimed to identify and quantify the postharvest diseases of guava accessions cultivated in organic system. For the characterization of diseases, 30 fruits from 48 accessions were evaluated in a completely randomized design. Anthracnose and black spot were the most frequent postharvest diseases in guava. The Vermelha Redonda (Shimoda), L5P21, L3P12, EEF-3, IAC-4 -Unesp and Monte Alto -Comum 1 accessions stood out with the lowest incidence of anthracnose and black spot, while L4P13, L1P2 and Creme Arredondada (Unesp) showed the highest incidence of anthracnose, black spot and stem-end rot. The Fusicoccum sp., Phomopsis sp., Phoma sp., Dothiorella sp. and Lasiodiplodia sp. pathogens were identified as the main responsible for causing stem-end rot symptoms

EFEITO DE EMBALAGENS COM ATMOSFERA MODIFICADA SOBRE OS ASPECTOS MICROBIOLÓGICOS E SENSORIAIS DE GOIABAS MINIMAMENTE PROCESSADAS

The aim of this study was to evaluate the effect of different packaging with modified atmosphere on the microbiological aspects and sensory acceptance of minimally processed �eKumagai�f and �ePedro Sato' guavas. Mix of �eKumagai�f and �ePedro Sato, in slices were wrapped in different packaging materials and stored at 5oC for six days. The packaging materials used were:polyethylene terephthalate containers; polypropylene bag 52 �Êm; polyolefin film Cryovac PD-900 58 �Êm; PVC stretch film 17 �Êm. Aciduric microorganisms, total coliforms and at 45oC and the presence / absence of Salmonella were analyzed. For the sensory evaluation was applied to the acceptance test. The guavas minimally processed wrapped PVC stretch film and PP film obtained greater acceptance for the sensory attribute appearance. The acceptance for the sensory attribute flavor of minimally processed guavas was positive in all treatments. The packaging did not affect the microbiological aspects of products, which showed low microbial count, in accordance with current legislation.O objetivo deste trabalho foi avaliar o efeito de diferentes embalagens com atmosfera modificada na qualidade microbiologica e sensorial de goiabas �eKumagai�f e �ePedro Sato�f minimamente processadas. Mix de goiabas �eKumagai�f e �ePedro Sato�f, em rodelas, foram embaladas em diferentes materiais de embalagem e armazenadas a 5oC, 70%UR por seis dias. Os materiais de embalagem utilizados foram: embalagens de tereftalato de polietileno (PET); filme de polipropileno de 52�Êm de espessura (PP); filme poliolefinico da Cryovac de 58�Êm (PD- 900); filme de policloreto de vinil de 17�Êm (PVC). Avaliou-se a contagem de microrganismos aciduricos, coliformes totais e a 45oC e presenca/ausencia de Salmonella. Para avaliacao sensorial aplicou-se o teste de aceitacao. As goiabas minimamente processadas e acondicionadas em embalagem de PVC e PP obtiveram maior aceitacao sensorial referente ao atributo aparencia. A aceitacao sensorial referente ao atributo sabor das goiabas minimamente processadas foi positiva em todos os tratamentos. A embalagem nao influenciou os aspectos microbiologicos dos produtos, que apresentaram baixa contagem microbiana, em acordo com a legislacao vigente

Effect of storage temperature on blackberry postharvest conservation

Blackberries have a relatively short shelf life, due to their fragile structure, high metabolism and incidence of diseases, thus requiring a careful storage. This study aimed at evaluating the effect of different temperatures on blackberry (Brazos cultivar) conservation, characterizing its physical and chemical attributes and quantifying the pathogens responsible for rottenness. A completely randomized experimental design, in a factorial scheme (temperatures x orchards), with three replications of 10 fruits per treatment, was used. The temperatures of 2 ºC and 5 ºC were effective in delaying the color change and degradation of organic acids. There was a significant increase in rottenness incidence with increasing storage temperature. Incidences lower than 7 % were observed at the end of storage at 2 ºC and 5 ºC, however, they exceeded 20 % at temperatures from 15 ºC. The main pathogens detected were Cladosporium spp. and Colletotrichum spp. Refrigeration at 2 ºC and 5 ºC is an efficient alternative to maintain the quality of blackberries up to nine days, for delaying fruit ripening and rottenness development

Peróxido de hidrogênio no controle de patógenos e do escurecimento enzimático de vagem minimamente processada

The objective of this study was to evaluate the efficacy of sanitization with hydrogen peroxide in reducing the enzymatic browning and pathogens of fresh cut snap bean. Fresh cut snap beans were inoculated by immersion in an Escherichia coli and Salmonella enteritidis contaminant solution Then, the vegetable was sanitized with hydrogen peroxide (0; 5; 10 and 20 mL L-1) for 10 minutes. The pathogens were monitored immediately after sanitization and after 4 days of storage at 10ºC. In other similar experiment, but without inoculation of pathogens, the snap bean were evaluated periodically. The surface color, pH, activity of phenylalanine ammonia-lyase, peroxidase and polyphenoloxidase enzymes, chlorophyll and carotenoids contents were evaluated. The sanitization with hydrogen peroxide reduced the count of E. coli and S. enteritidis, being similar for different hydrogen peroxide concentrations. The browning of the section surface of snap bean was controlled by hydrogen peroxide in the concentration of 20 mL L-1. The activity of the enzymes as well as the pigments content (chlorophyll and carotenoids) were not affected by treatments, except the polyphenoloxidase enzyme. The pH increased during storage and was greatest in snap bean sanitized with 20 mL L-1. The sanitization with hydrogen peroxide is effective in reducing population of E.coli and S. enteritidis and minimizing browning in fresh cut snap bean, but caused spots on the vegetable skin, precluding its use.O objetivo deste trabalho foi avaliar a eficácia da sanificação com peróxido de hidrogênio em minimizar o escurecimento enzimático e reduzir patógenos em vagem minimamente processada. Vagens minimamente processadas foram inoculadas por imersão em solução contaminante de Escherichia coli e Salmonella enteritidis e sanificadas com peróxido de hidrogênio (0, 5, 10 e 20 mL L-1) por 10 minutos. A população de patógenos foi monitorada imediatamente após a sanificação e no quarto dia de armazenamento a 10ºC. Em outro experimento similar, porém sem a inoculação dos patógenos, as vagens foram avaliadas periodicamente quanto à: coloração da superfície da casca e corte; pH; atividade das enzimas fenilalanina-amônia-liase, peroxidase e polifenoloxidase; teor de clorofila e carotenoides. A sanificação reduziu a contagem de E. coli e S. enteritidis, sendo essa redução similar nas diferentes concentrações de peróxido. O escurecimento da superfície de corte das vagens foi minimizado pelo peróxido de hidrogênio na concentração de 20 mL L-1. As atividades das enzimas, assim como o teor de clorofila e carotenoides não foram afetados pelos tratamentos, exceto a polifenoloxidase. O pH aumentou durante o armazenamento, sendo maior nas vagens sanitizadas com 20 mL L-1 de peróxido. Conclui-se que a sanificação com peróxido de hidrogênio é eficaz em reduzir a população de E. coli e S. enteritidis bem como minimizar o escurecimento na superfície de corte da vagem, porém ocasiona manchas na casca das vagens minimamente processadas, inviabilizando sua utilização

Temporal progress and spatial patterns of quiescent diseases in guava influenced by sanitation practices

ABSTRACT: Postharvest diseases are a major problem in guava crops as the symptoms normally appear during fruit ripening. This study aimed to detect and characterize the temporal dynamics and spatial patterns of the most important guava diseases in orchards with and without removal of crop residues as a sanitation practice. The experiment was conducted in an orchard of ‘Pedro Sato’ guavas, over two consecutive seasons, and data were collected from the flowering to the fruit ripening stage. In immature guavas treated with paraquat and ethrel, Colletotrichum spp. was detected from the 5th day of incubation. Anthracnose was detected in flowers at incidences higher than 50 % and black spot in fruit larger than 5.5 cm in length. The monomolecular and the exponential models provided the best fit to anthracnose and black spot incidence progress curve data, respectively. Both diseases showed a predominantly random spatial pattern in the orchard. The removal of crop residues reduced the rate of disease progress in at least one season, and was effective in reducing the areas under the quiescent disease progress curves (AUDPC) of anthracnose. Anthracnose incidence increased from 57 to 96 % and black spot from 1 to 48 %, respectively, at fruit maturation levels 1 and 3. A negative correlation was found between disease incidence and the color of the fruit skin (°h). Fruit harvested during the later maturation stages showed higher incidence of the diseases. Due to the wide distribution and early infection of quiescent diseases, starting at flowering, preventive management should consider disease monitoring and removal of crop residues