A produção brasileira de morangos no ano de 2007 foi estimada em aproximadamente 100 mil toneladas, com uma área ocupada de 3.500 ha (ANTUNES et al., 2007), uma produção pequena quando comparada a de outros países como os EUA, que alcança 998,8 mil toneladas (USDA, 2005). Entretanto, a produção nacional de morangos se expande a cada ano, com predominância do cultivo em pequenas propriedades rurais. Por se tratar de exploração que agrega mão de obra familiar, possui grande importância econômica e social, caracterizando-se em excelente fonte de renda para pequenas propriedades.Por ser um produto de alta perecibilidade no mercado in natura, o morango requer a utilização de tecnologia adequada para melhor conservação. Uma alternativa para aumentar o prazo de vida útil do morango in natura seria submetê-lo ao processamento mínimo, com adoção de etapas que possam garantir um produto que atenda à demanda do mercado consumidor atual, com tendência de consumo crescente de alimentos saudáveis, frescos e de alta qualidade. Entre os tratamentos que são aplicados a morangos in natura citam-se a imersão em solução contendo cálcio, para manter a firmeza (GARCÍA; HERRERA; MORILLA, 1996;CAMARGO et al., 2000; MISHA, 2001), manutenção em embalagens com atmosfera modificada ou controlada (AHAONI; BARKAI-GOLAN, 1987;SMILANICK;CRISOSTO;MLIKOTA, 1999;CALEGARO;PEZZI;BENDER, 2002;MORAES et al., 2008); recobrimento comestível (GARCÍA; MEDINA; OLÍAS, 1998; HENRIQUE; AbstractThis study aimed to evaluate the physical-chemical and microbiological changes in strawberries subjected to the fresh-cut process. The effects on the contaminants and texture of strawberries washed with calcium chloride and polyethylene glycol and of ozone gas and organic chlorine as sanitizer to reduce microbial contamination were evaluated. Analyses of texture, color, weight loss and microbial contaminants were made during storage at 5 °C for 12 days in packs wrapped in up to four layers of PVC film. The addition of 0.5, 1.0 and 1.5% of calcium chloride or 0.5% of polyethylene glycol in the washing water did not ensure the maintenance of the texture of the strawberry at the end of the period of storage. The ozonation of strawberries for 60 minutes was more effective in reducing (p < 0.05) the count of mesophilic aerobics microorganisms, yeasts and molds and coliforms, when compared to results obtained with strawberries ozonizated for 30 minutes and immersed in a solution of organic chlorine. The strawberries stored in packages covered with three layers of PVC film showed an increase in texture and intensity of browning and a reduction in microbial contaminants. The main molds isolated on the strawberry were of the genus Fusarium and the species Cladosporium cladosporioides.

The aim of this work was to evaluate a quorum-quenching approach to identify functions regulated by quorum sensing in Enterobacter cloacae. We employed an aiiA transconjugant strain of E. cloacae that synthesizes a lactonase enzyme that hydrolyzes N-acyl homoserine lactone signaling molecules to compare bacterial phenotypes in the presence and absence of quorum signals. The aiiA-expressing strain displayed increased proteolytic activity and intensity of a milk-clotting reaction when compared to the wild-type strain. Although both strains growing on polystyrene plates in rich media and a minimal medium of salts formed biofilms, the wild-type strain exhibited a higher number of adhered cells. On the surface of stainless steel coupons that were submerged in culture media, the number of adhered cells of the wild type contained up to one log more cells compared with the aiiA transconjugant. However, after 48 h of incubation, there was no significant difference between the strains. The results demonstrated that the quorum-sensing system negatively regulates proteolytic activity and is likely involved in the early steps of biofilm formation by E. cloacae 067.