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United States Department of Agriculture

Agricultural Research Service

Title: Postharvest Quality of Tomatoes Produced in Organic and Conventional Production Systems

Authors
item MCCOLLUM, THOMAS
item Chellemi, Daniel
item ROSSKOPF, ERIN
item Church, Gregory
item PLOTTO, ANNE

Submitted to: American Society of Horticulture Science Meeting
Publication Type: Abstract Only
Publication Acceptance Date: March 1, 2005
Publication Date: July 1, 2005
Citation: Mccollum, T.G., Chellemi, D.O., Rosskopf, E.N., Church, G.T., Plotto, A. 2005. Postharvest quality of tomatoes produced in organic and conventional production systems. American Society of Horticulture Science Meeting, July 2005. Hort Science, Vol.40(4),p.959.

Interpretive Summary: Consumer demand for organically grown produce is increasing annually. In addition to the lack of contamination by synthetic pesticides, there is a perception that organically grown produce quality is superior to that of conventionally grown produce. We conducted experiments to compare the quality of tomatoes grown using standard commercial practices with tomatoes grown organically. We found little difference in color, firmness, soluble solids or acidity between conventional grown and organically grown fruit. However, taste panelists were able to reliably distinguish between conventional and organic tomatoes based on flavor, aroma and mouth-feel. Taste panelists also indicated a preference for the organically grown tomatoes. Our results suggest that organic production practices may in fact affect the eating quality of tomatoes, but additional research will be necessary to confirm our findings and determine precisely how the chemical composition of tomato fruit may be affected by organic production.

Technical Abstract: Research is being conducted at the USHRL, Fort Pierce, Florida to develop production practices for field-grown vegetables that do not rely on soil fumigation with methyl bromide. Field trials which included conventional and organic tomato production systems were established in 2000. Although the initial objective of the experiment was to determine effects of land management systems on soil health and crop yield, the fruit produced provided a unique opportunity to compare directly the quality of tomatoes produced using conventional practices with those grown organically. In Dec. 2003 and Jan. 2005 fruit were harvested at the breaker stage and ripened at 20C. When fruit were determined to be fully ripe by visual inspection, samples were collected for quality analyses (color, firmness, total soluble solids, pH and total acidity). In each year, no significant differences between treatments for color or total soluble solids were detected. In 2003, total acidity was the only quality parameter that differed significantly (0.40% vs. 0.44% total acidity) between conventional and organic fruit, respectfully. In 2005, conventional fruit had significantly higher soluble solids (4.4 vs. 4.0 °Brix) and were firmer (2.5 mm vs. 3.4 mm deformation) than organic fruit. Sensory evaluation (duo-trio test with balanced reference) was conducted in 2005 to determine whether consumers could perceive a difference between tomatoes grown conventionally or organically. Panelists could perceive the difference between conventional and organic tomatoes by smell or taste at alpha<0.001. Quality analyses of samples conducted on the same group of fruit used for sensory evaluation indicated no significant difference in any quality parameter except fruit firmness; with conventional tomatoes being more firm (3.0 mm deformation) than organic tomatoes (4.3 mm deformation). Organic tomatoes were perceived by some of the panelist to be softer, and were preferred because of their taste, flavor, texture and juiciness. Alternatively, conventional tomatoes were described as “not as ripe”, “dry”, and having “less aroma”. Our results do not allow us to conclude unequivocally that the sensory panel was truly able to distinguish conventional from organically grown fruit as a consequence of production system or if they were merely detecting a difference in ripeness.

Last Modified: 8/19/2014
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