ABSTRACT
Information about the availability of soil mineral nitrogen (N) in organic greenhouse tomatoes after the application of mobile green manure (MGM), and its impact on plant nutrient status and yield is scarce. Considering this knowledge gap, the effects of legume biomass from faba beans that are cultivated outdoors (FAB), or from feed-grade alfalfa pellets at two different doses (AAL = 330 g m-2; AAH = 660 g m-2) that were applied as MGM on the nutrition and yield of an organic greenhouse crop of tomatoes were evaluated. All of the MGM treatments increased the mineral N concentrations in the soil throughout the cropping period, and the total N concentration in tomato leaves when compared to the untreated control. FAB and AAH treatments had a stronger impact than AAL in all of the measured parameters. In addition, AAL, AAH, and FAB treatments increased the yield compared to the control by 19%, 33%, and 36%, respectively. The application of MGM, either as faba bean fresh biomass or as alfalfa dry pellets, in organic greenhouse tomatoes significantly increased the plant available soil N, improved N nutrition, and enhanced the fruit yield. However, the N mineralization rates after the MGM application were excessive during the initial cropping stages, followed by a marked decrease thereafter. This may impose an N deficiency during the late cropping period.
ABSTRACT
In view of the need to in form the producers, dealers and consumers about the capability of the vegetables in being a vehicle for microorganisms, they should receive suitable hygienic and sanitary treatment. This paper aimed at evaluating the microbiological quality of organic and conventional tomatoes (Lycopersiconesculentum Mill.) commercialized in Curitiba city, southern Brazil. Eight samples of conventional tomatoes and four samples of organic tomatoes were collected from different sites. The microbiological analyses for detecting Salmonella spp and molds and yeasts were conducted according to the Compendium of Methods for Microbiological Examination of Foods. Total coliforms and Escherichia coli were analyzed by the PetrifilmTM methodology. The data were analyzed by variance analysis and Tukey tests. No Salmonella sp was isolated from 25 g of tomato samples. The total coliform counts ranged up to 1.4x103CFU/g and Escherichia coli up to 2.3x102 CFU/g in conventional tomatoes. Yeasts and molds were foundin conventional tomato samples up to 2.1x10, and up to 1.04 x 1012 CFU/g in organic tomato samples. This study clearly shows that the tomatoes ought to receive suitable hygienic and sanitary treatment before being commercialized.
Subject(s)
Food, Organic , Microbiological Techniques , Solanum lycopersicum , SalmonellaABSTRACT
The consumption of organic tomatoes (ORTs) reduces the risk of harmful effects to humans and the environment caused by exposure to toxic agrochemicals. In this study, we used the somatic mutation and recombination test (SMART) of wing spots in Drosophila melanogaster to evaluate the genotoxicity of ORT and the effect of cotreatment with ORT on the genotoxicity of Doxorubicin(®) (DXR, a cancer chemotherapeutic agent) that is mediated by free radical formation. Standard (ST) cross larvae were treated chronically with solutions containing 25%, 50% or 100% of an aqueous extract of ORT, in the absence and presence of DXR (0.125 mg/mL), and the number of mutant spots on the wings of emergent flies was counted. ORT alone was not genotoxic but enhanced the toxicity of DXR when administered concomitantly with DXR. The ORT-enhanced frequency of spots induced by DXR may have resulted from the interaction of ORT with the enzymatic systems that catalyze the metabolic detoxification of this drug.
ABSTRACT
The consumption of organic tomatoes (ORTs) reduces the risk of harmful effects to humans and the environment caused by exposure to toxic agrochemicals. In this study, we used the somatic mutation and recombination test (SMART) of wing spots in Drosophila melanogaster to evaluate the genotoxicity of ORT and the effect of cotreatment with ORT on the genotoxicity of Doxorubicin® (DXR, a cancer chemotherapeutic agent) that is mediated by free radical formation. Standard (ST) cross larvae were treated chronically with solutions containing 25%, 50% or 100% of an aqueous extract of ORT, in the absence and presence of DXR (0.125 mg/mL), and the number of mutant spots on the wings of emergent flies was counted. ORT alone was not genotoxic but enhanced the toxicity of DXR when administered concomitantly with DXR. The ORT-enhanced frequency of spots induced by DXR may have resulted from the interaction of ORT with the enzymatic systems that catalyze the metabolic detoxification of this drug.
