Antimony (Sb) Found in Kirkland (Costco) Organic Peanut Butter Plastic Jars

Antimony Found in Kirkland (Costco) Organic Peanut Butter Plastic Jars

After publishing THIS POST (which has since unexpectedly gone viral!) simply recommending that folks not purchase peanut butter in plastic jars & instead purchase peanut butter in glass whenever possible, a lot of people responded with links and information either supporting or attempting to dismiss or refute my concerns.

One of my readers posted several links attempting to dismiss the concerns — but each of the links he posted mentioned the possibility of Antimony (elemental symbol “Sb”) in the PET plastic that most plastic peanut butter jars are made of.

This piqued my interest.

I know that Antimony is a toxicant, a known possible carcinogen that has been documented to be the source of health issues in humans (and – for example – has also been found in detectable levels in the breast tissue of women with breast cancer.)

Read more about antimony toxicity here.

My thought was that if Antimony is present at ANY LEVEL in a plastic FOOD container that only supported my recommendation to avoid plastic food containers altogether (especially with foods that have to be heated for packaging, like peanut butter).

People arguing the “other side” (pro-plastic) might say that the Antimony hasn’t been shown to migrate “except under certain conditions” (e.g. higher temperatures than the stored jars might normally be expected to encounter in a pantry, longer shelf storage than is generally common, etc.), however (again, in my opinion) the mere presence of Antimony (along with my solid knowledge that the historic and current regulatory actions and standards of our government are woefully inadequate when it comes to toxicants) is a concern. A big concern.

Not surprisingly, the International Antimony Association (at assures us that the presence of Antimony in these jars is perfectly safe.

Click the image below to see the full-size PDF.

To see all of my posts related to peanut butter, click here.

Just because a substance has not (yet) been shown to migrate under “certain conditions” does not mean the studies done were comprehensive enough, nor that the low threshold of detection set as the limit for the study are necessarily actually levels that are protective of human health.*

*For example, many vitamins and supplement manufacturing companies do toxicant testing on their products and share their results with their customers.

These results usually list the low threshold of detection for Lead as a number in the single or double digit parts per million (ppm), when Lead is a known toxicant in ingested items in the single and double digit parts per billion (ppb).

As a result the company might state “there is no detectable Lead” in their product – but they are not actually looking for Lead levels at a threshold that is protective of human health for ingested items (parts per billion). Said another way, their “low threshold” is too high. They are also not regulated in a way that requires that level of specificity in their testing.

Antimony Found in Kirkland (Costco) Organic Peanut Butter Plastic Jars

Test #1, Kirkland Organic Peanut Butter Jar

Here what I found when I tested a Kirkland peanut butter jar (pictured above and below) for Antimony, the very jar of peanut butter that inspired me to write the original post (see images of readings below). Please note these are test results for a full jar of peanut butter and the therefore the actual antimony levels of the plastic would likely be much higher if the plastic were tested by itself.:

Test One (181.1 seconds/3 minutes):

  • Antimony (Sb): 55 +/- 18 ppm
  • Arsenic (As): 2 +/- 1 ppm

Test Two (180.9 seconds/3 minutes):

  • Antimony (Sb): 58 +/- 17 ppm

Click here to learn more about XRF testing/instrumentation.

Antimony Found in Kirkland (Costco) Organic Peanut Butter Plastic Jars

Test #2, Kirkland Organic Peanut Butter Jar

So both tests found Antimony and one found (a very low level of) Arsenic! [The Arsenic test may or may not be replicable – because it was so low, and may be an anomaly, I would have to do more testing to confirm that.]

While I am a Lead expert (and not an Antimony expert) and I don’t know the implications of these specific levels of Antimony, I personally don’t think there should be any Antimony in food packaging – especially when there are toxicant-free options already readily available.

In general when we discuss toxicant levels in food we are talking about parts per billion (not parts per million) as causing harm, so for there to be levels this high (in ppm) in the packaging I have definite concerns for what the ppb levels of the toxicant might be in the food contents of this packaging.

In my opinion, as a mother of children who have significant health issues and disabilities due to exposure to toxicants (in our case, specifically due to Lead exposure) I think it verges on criminal that there is not a label on this product (and similar products) that says:

“Warning: The packaging of this food product contains ANTIMONY, a toxicant that is well-documented to be harmful to human health and is a known possible carcinogen.”

As always, please let me know if you have any questions.

Thank you for reading and for sharing my posts.

If you want to directly support this 100% independent consumer goods testing work please do consider making a contribution to my GoFundMe. The XRF instrument that I use for testing generally can cost as much as $750 a day to rent (or more!) and I couldn’t do the work I do without the support of my readers. [I am currently working to cover an outstanding XRF rental bill of about $4,700.]

Thank you again!

Tamara Rubin

*Links to Amazon are affiliate links. If you purchase something after clicking on one of these links I may receive a small percentage of what you spend at no extra cost to you.  Links to Kirkland Peanut Butter on Amazon are for informational purposes only – I do not recommend purchasing this product.

Antimony Found in Kirkland (Costco) Organic Peanut Butter Plastic Jars Antimony Found in Kirkland (Costco) Organic Peanut Butter Plastic Jars


6 Responses to Antimony (Sb) Found in Kirkland (Costco) Organic Peanut Butter Plastic Jars

  1. Anna October 23, 2018 at 2:04 pm #

    How much antimony was found in just the peanut butter itself?

    • Tamara October 23, 2018 at 2:12 pm #

      I did not test the peanut butter. I don’t have an available method to do that. If you want to test the peanut butter you would need to send it to a lab and ask that they test it down to single digit parts per billion (ppb), not parts per million (ppm) – because these toxicants are generally harmful to human health in the range of ppb.

  2. Olga January 17, 2019 at 10:13 am #

    We eat a lot of that peanut butter! How sad! Have you tested organic raw almond butter from Trader Joe’s? I was thinking that since it’s raw, it shouldn’t be exposed to high heat levels although again it’s not regulated and they can put anything they want on a package.

    On another note I’ve read that a lot of glassware like wine decanter etc. contain dengoerous levels of lead. Have you tested the glass jars of recomended by you brands for lead?

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