An Improved Grading System For Measuring Plant Diseases Vol-36

BACKGROUND
The health benefits of organic foods are unclear.


PURPOSE
To review evidence comparing the health effects of organic and conventional foods.


DATA SOURCES
MEDLINE (January 1966 to May 2011), EMBASE, CAB Direct, Agricola, TOXNET, Cochrane Library (January 1966 to May 2009), and bibliographies of retrieved articles.


STUDY SELECTION
English-language reports of comparisons of organically and conventionally grown food or of populations consuming these foods.


DATA EXTRACTION
2 independent investigators extracted data on methods, health outcomes, and nutrient and contaminant levels.


DATA SYNTHESIS
17 studies in humans and 223 studies of nutrient and contaminant levels in foods met inclusion criteria. Only 3 of the human studies examined clinical outcomes, finding no significant differences between populations by food type for allergic outcomes (eczema, wheeze, atopic sensitization) or symptomatic Campylobacter infection. Two studies reported significantly lower urinary pesticide levels among children consuming organic versus conventional diets, but studies of biomarker and nutrient levels in serum, urine, breast milk, and semen in adults did not identify clinically meaningful differences. All estimates of differences in nutrient and contaminant levels in foods were highly heterogeneous except for the estimate for phosphorus; phosphorus levels were significantly higher than in conventional produce, although this difference is not clinically significant. The risk for contamination with detectable pesticide residues was lower among organic than conventional produce (risk difference, 30% [CI, -37% to -23%]), but differences in risk for exceeding maximum allowed limits were small. Escherichia coli contamination risk did not differ between organic and conventional produce. Bacterial contamination of retail chicken and pork was common but unrelated to farming method. However, the risk for isolating bacteria resistant to 3 or more antibiotics was higher in conventional than in organic chicken and pork (risk difference, 33% [CI, 21% to 45%]).


LIMITATION
Studies were heterogeneous and limited in number, and publication bias may be present.


CONCLUSION
The published literature lacks strong evidence that organic foods are significantly more nutritious than conventional foods. Consumption of organic foods may reduce exposure to pesticide residues and antibiotic-resistant bacteria.


PRIMARY FUNDING SOURCE
None.

Are organic foods safer or healthier than conventional alternatives? a systematic review

Grafting as a tool to improve tolerance of vegetables to abiotic stresses: Thermal stress, water stress and organic pollutants

Factors affecting the postharvest soluble solids and sugar content of tomato (Solanum lycopersicum L.) fruit

The stability and decomposition of biochar are fundamental to understand its persistence in soil, its contribution to carbon (C) sequestration, and thus its role in the global C cycle. Our current knowledge about the degradability of biochar, however, is limited. Using 128 observations of biochar‐derived CO2 from 24 studies with stable (13C) and radioactive (14C) carbon isotopes, we meta‐analyzed the biochar decomposition in soil and estimated its mean residence time (MRT). The decomposed amount of biochar increased logarithmically with experimental duration, and the decomposition rate decreased with time. The biochar decomposition rate varied significantly with experimental duration, feedstock, pyrolysis temperature, and soil clay content. The MRTs of labile and recalcitrant biochar C pools were estimated to be about 108 days and 556 years with pool sizes of 3% and 97%, respectively. These results show that only a small part of biochar is bioavailable and that the remaining 97% contribute directly to long‐term C sequestration in soil. The second database (116 observations from 21 studies) was used to evaluate the priming effects after biochar addition. Biochar slightly retarded the mineralization of soil organic matter (SOM; overall mean: −3.8%, 95% CI = −8.1–0.8%) compared to the soil without biochar addition. Significant negative priming was common for studies with a duration shorter than half a year (−8.6%), crop‐derived biochar (−20.3%), fast pyrolysis (−18.9%), the lowest pyrolysis temperature (−18.5%), and small application amounts (−11.9%). In contrast, biochar addition to sandy soils strongly stimulated SOM mineralization by 20.8%. This indicates that biochar stimulates microbial activities especially in soils with low fertility. Furthermore, abiotic and biotic processes, as well as the characteristics of biochar and soils, affecting biochar decomposition are discussed. We conclude that biochar can persist in soils on a centennial scale and that it has a positive effect on SOM dynamics and thus on C sequestration.

Biochar stability in soil: Meta-analysis of decomposition and priming effects

It is widely accepted that a healthy diet is an important factor in preventing chronic diseases, and in improving energy balance and weight management. Studies have shown strong inverse correlations between tomato consumption and the risk of certain types of cancer, cardiovascular diseases and age-related macular degeneration. Because tomato is the second-most important vegetable in the world after potato, this horticultural crop constitutes an excellent source of health-promoting compounds due to the balanced mixture of minerals and antioxidants including vitamins C and E, lycopene, β-carotene, lutein and flavonoids such as quercetin. Improvement in phytonutrients in tomatoes can be achieved by cultivar selection, environmental factors, agronomic practices, stage of ripeness at harvest, and appropriate handling and conditioning all the way from the field to the consumer. The purpose of this paper is to review the recent literature of the main factors that can improve the nutritional quality of tomato and consequently their beneficial role in human diet. The importance of genotype selection and the optimization of environmental conditions (light, temperature, humidity, atmospheric CO2 and air pollutants) for high nutritional value is outlined first, followed by the optimization of agricultural practices (soil properties, water quality, mineral nutrition, salinity, grafting, pruning, growing systems, growth promoters, maturity, and mechanical and pest injuries). The review concludes by identifying several prospects for future research such as modelling and genetic engineering of the nutritional value of tomato.

Tomato (Solanum lycopersicum) health components: from the seed to the consumer

Greenhouse Tomato Fruit Quality

The processes that determine tomato crop growth and yield are considered in detail, with emphasis on the influence of environmental factors such as light, CO2, temperature, humidity and salinity. The main topics are as follows: Biomass production (leaf area and light interception, leaf and crop photosynthesis); Crop and fruit growth; Biomass partitioning (source strength, transport path, sink strength, shoot:root ratio, and influence of growing conditions and cultural practices); Fruit dry matter content; and Crop growth models (describing the TOMSIM model for tomato growth, development and yield, and its use in 2 case studies on optimum fruit number/truss and mitigation of salinity effects on yield by improving LAI).

Crop growth and yield

Measurement of fresh tomato fruit overall quality, and particularly lycopene content, is challenging in the context of high-volume production. An experiment was conducted to simultaneously measure various quality parameters of tomato in a nondestructive manner using vis−NIR reflectance spectroscopy and chemometrics. The sampling set included different cultivars that are obtainable from both retailers’ shelves and two greenhouse producers. Results indicate that lycopene content was accurately predicted [r2 = 0.98; root mean square error of cross-validation (RMSECV) = 3.15 mg/kg], along with color variables such as Hunter a (r2 = 0.98), L, and b (r2 = 0.92). Tomato color index (TCI) was better predicted (r2 = 0.96) than the a/b ratio (r2 = 0.89). Firmness prediction, with an r2 of 0.75, is comparable to what is reported in the literature for other fruits and may have a practical interest. Prediction of internal quality such as pH, soluble solids, titratable acidity, and electrical conductivity was less accu...

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Martine Dorais

Papers

Tomato (Solanum lycopersicum) health components: from the seed to the consumer

Greenhouse Tomato Fruit Quality

Crop growth and yield

Nondestructive measurement of fresh tomato lycopene content and other physicochemical characteristics using visible-NIR spectroscopy.

Effects of supplemental light duration on greenhouse tomato (Lycopersicon esculentum Mill.) plants and fruit yields