Psst... We're working on the next generation of Chowhound! View >
HOME > Chowhound > General Topics >
Jan 24, 2010 06:45 PM

Companies that will run toxicology tests on food samples?

Does anyone know of any (hopefully reputable) private or public labs that will measure levels of pesticides and other chemicals on food samples submitted by consumers?

I would like to have some dried sorrel leaves tested. I love to use the sorrel to make an herbal tea, but I am concerned about pesticide residues that may be on the leaves. I'd also be interested in having some teas tested.

  1. Click to Upload a photo (10 MB limit)
  1. I don't have a good answer for you, but as a scientist in academia, I can tell you that it could be EXTREMELY expensive if you want the sample to be screened for multiple compounds (our facility would charge ~$300 to check for a single chemical, so if you want to check for multiple pesticides, and their oxidative metabolites, and heavy metals, you're easily looking at $5000 for a complete panel). And then there's the issue that different pesticides (if any) might be used at different times of the year, so submitting a single sample might not be representative.

    In the Pacific NW, sorrel grows like crazy. Probably easiest to grow your own or purchase from a reputable organic farm.

    2 Replies
    1. re: chococat

      $5,000?? I was afraid of that. I was hoping for some kind of screening panel that would be under $300. With so much money to be made in the selling of "organic" produce, it would seem that the demand for this kind of testing could be pretty high.

      Growing my own sorrel isn't really an option in my current living situation.
      And it would be nice to be able to test some of the imported teas.

      1. re: racer x

        It's a fairly involved process to detect the needle in the haystack, you're looking for compounds in the parts per billion range. First, the leaves would have to be processed (which would require a fair amount of leaves) and the residues concentrated. Then the sample has to be analyzed in a piece of equipment (probably a mass spectrometer), which requires a skilled operator and expensive maintenance, not to mention a $500K initial investment. It's not a trivial process.

        The idea of "screening" for multiple pesticides (and there are dozens of commonly used pesticides, and even more if your product is from outside the USA) is complicated by the fact that most pesticides will degrade when exposed to air, water, UV light and heat, so to get a complete picture of what may be present, you really need to look for the parent compound, as well as it's metabolites.

        There are some cheap pesticide test kits (usually used to test water quality) that you can try, but you'd have to make sure you run a control sample with the water you use to brew the tea (google: pesticide test kit). They're cheap (and fun, if you're a nerd like me!) but I can't really say how informative they might be.