Organic farming exposes plants to more stressful growing conditions than conventional farming, and it is for this reason that organic tomatoes were found to have higher levels of vitamin C, higher levels of sugar (which could enhance their flavor), and higher levels of the antioxidant lycopene, which researchers believe the tomatoes developed in response to that stress. As we recently reported, the potent antioxidant lycopene, which gives the tomato its rich red color, has been linked to reductions in stroke risk.

In the new study, appearing in the journal PLOS ONE, the researchers from the Federal University of Ceara in Brazil, compared the biochemical properties and the weights of organic tomatoes to those grown at conventional farms. The organic tomatoes were 40 percent smaller and also accumulated more of the stress-resistance-related compounds than the conventionally grown tomatoes.

Tomatoes rank 29 on the Environmental Working Group’s 2012 list of 49 produce items analyzed according to the amount of pesticide residue each contained. The lower the ranking number, the more pesticides were found to be present. Tomatoes were about the middle of the pack, whereas the produce that ranked first, second, and third, apples, celery and red bell peppers, respectively, rank top on the group’s so-called Dirty Dozen foods that you want to buy organic whenever possible.

Not all are convinced that organic tomatoes are necessarily better. The study finding could have less to do with organic growing techniques and more to do with the type of varieties the tomatoes were, one University of Florida tomato researcher told NPR, adding that certain plant varieties were created to yield higher numbers of fruit, which dilutes each fruit’s nutrient amounts.

Regardless of which method of tomato you purchase, proper rinsing technique is essential. One study found that rinsing produce under tap water for one minute to be just as effective as rinsing with soap-and-water and other solutions in significantly reducing residues of up to 12 pesticides, according to The New York Times, and another study found using a solution containing about 10 percent vinegar was able to reduce bacteria by 90 percent, and viruses, by 95 percent.

Do You tend to buy most of your produce organic or conventionally grown?