Produce Pesticide Rankings Part 1

My post Details on the Dirty Dozen on EWG’s Shopper’s Guide to Pesticides™ led me to dive into the 2008 USDA data to see just how contaminated (or not) our produce really is. There’s so much information that it’s a little difficult to work with, but with perseverance and the right software (JMP is the best!*), I was able to re-do the EWG analysis but with the newest available data.

Below you can find my results with a through explanation of what I’ve done and why. The results are posted without all the commentary at Produce Pesticide Rankings which has all of the results and Pesticide Produce Rankings Tables which has comparisons of my results to the EWG results. You can download the original USDA data yourself or check out the Latest PDP Findings of Interest to Consumers.

See Produce Pesticide Rankings Part 2 for the real scoop on which produce is the most and least safe.

Continue reading…

Details on the Dirty Dozen

As you may already know, the Environmental Working Group is a 501(c)(3) NGO with the goal of protecting “kids from toxic chemicals in our food, water, air and the products we use every day”. One of their major efforts is the yearly Shopper’s Guide to Pesticides™.

EWG gives many many reasons why they think you should use the guide, specifying that you (the consumer) should eat organic or at least choose the Clean 15™ over the  Dirty Dozen™:

The 12 most contaminated fruits and vegetables (the “Dirty Dozen”) are contaminated with an average of 10 different pesticides, with many tainting more than one type of produce. In contrast, the “Clean 15,” the 15 least contaminated fruits and vegetables, contain an average of less than 2. Eating organic food lowers pesticide body burdens as well. Research shows that concentrations of pesticides in children’s bodies peak during seasons that they eat the most produce, but fall to below detectable levels in just 5 days when they eat organic food.

The list of reasons has a lot of scary facts about how many pesticides detected on food, just how “polluted” our bodies are from the things we eat, and explains how our government barely regulates pesticides. Near the bottom, EWG lets us know that despite the scary facts that the need to eat fresh produce outweighs any risk from pesticide residues. They also remind consumers of the importance of eating fresh produce on their FAQ page. Unfortunately, I’m not sure if anyone gets to that part, considering that media coverage of the Shopper’s Guide rarely mentions it, instead focusing on the scary facts (as in ‘Dirty dozen’ produce carries more pesticide residue, group says on CNN Health, which dismisses the silly government for thinking that small amounts of pesticides won’t hurt us).

The truth is, pesticides are scary. As EWG’s Amy Rosenthal says, “Pesticides are designed to kill things.”

The devil, as always, is in the details.

Continue reading…

Bt FAQ

Bt, short for Bacillus thuringiensis, is a bacteria that produces a protein that kills certain types of insects. Different types of the gene that produces thais protein have been engineered into crops to make them resistant to those insects. The approach has been quite successful but the details can be confusing.

If you’re looking for science-based information on Bt crops, check out the Bacillus thuringiensis info page that was developed by Karen Chien of

Continue reading…

Can you help Biofortified?

In the interests of making science-based information about biotechnology easily available to everyone, we’re working on a few resource pages that you can find in the header under “Resources”. One such page is a list of traits that have been developed with biotechnology. It’s incomplete at the moment, but I’d like to ask your help with creating this resource. I hope you’ll visit the page and post in the Forum if you have links

Continue reading…

New possibilities for drought tolerance

This image is an extreme closeup of a stomate (singular, the plural form is stomata). These two cells, called guard cells, control the plant’s respiration: how much carbon dioxide gets in and how much oxygen and water vapor gets out. The control isn’t very good, though. Most plants just have their stomata open all day every day so they can pull in lots of CO2 to use during photosynthesis to make sugar. And that means a lot of water, painstakingly pulled up from the soil, through the roots, gets lost. If stomata could be more selective, only opening when more CO2 was needed for photosynthesis, then water could be conserved.

An enzyme called carbonic anhydrase raises the levels of CO2 in chloroplasts so the plant can make plenty of sugar. It does this by converting CO2 from its storage form carbonic acid back to it’s useable form: CO2 + H2O ⇌ H2CO3.

Carbonic anhydrase also appears in the guard cells, where it controls the opening and closing of stomata.

Continue reading…