Which sourdough bread at the grocery store does NOT have detectable glyphosate, a very common toxic herbicide? Glyphosate is the active ingredient in “Roundup Ready” GMO crops and has been linked with cancer. If you want to avoid glyphosate and other hormone-disrupting chemicals, Mamavation is your one-stop shop for the safest food and products online. You’ve trusted Mamavation to bring you topics like (1) safest cooking oils tested for phthalates, (2) safest coffee tested for pesticides & PFAS, (3) safest tea tested for PFAS, and (4) women’s multivitamins tested for pesticides, PFAS, heavy metals, & phthalates, now join us as we bring you sourdough bread tested for glyphosate.
Disclosure: This consumer study is released in partnership with Environmental Health News. Scientific review was done by Terrence Collins, Teresa Heinz Professor of Green Chemistry & Director of the Institute for Green Sciences at Carnegie Mellon University. Donations were provided by Environmental Health News and Mamavation community members. Note that Mamavation has only “spot-checked” the industry and thus we cannot make predictions about brands and products that we have not tested. Products and manufacturing aides can change without notice, so buyer beware. This post contains affiliate links, most of which are to Amazon, which means Mamavation will receive a portion of those sales, and we will use that to pay ourselves back for the testing. You can also give a tax-deductible donation to our consumer studies here through Environmental Health Sciences. Thank you! Copyright © 2026 Mamavation — All Rights Reserved
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Glyphosate–A Powerful Toxic Herbicide That Has Taken Over World
Glyphosate [N-(phosphonomethyl) glycine] is the active ingredient in glyphosate-based herbicides (GBH) and is also the most popular herbicide in the world. Its environmental presence increased sharply after the introduction of “Roundup Ready” crops in 1996, which allowed glyphosate to be sprayed onto crops without killing them. Beyond agriculture, glyphosate is extensively used in landscaping, roadside maintenance, golf courses, and vegetation control in fire-prone areas.
Environmental exposure to this broad-based herbicide has increased dramatically since the introduction of “Round-up Ready” genetically modified (GMO) crops in 1996 for soybean, maize, and cotton varieties. “Round-up Ready” genetically modified crops made it possible to utilize glyphosate as a broadcast herbicide while not killing the crops they were sprayed on. Glyphosate is also extensively used in deforestation efforts, such as killing brush in fire zones, and is relied on heavily by landscapers to kill weeds in green belts and on golf courses. Ultimately, glyphosate is used to eliminate weeds and shrubs, including annual and perennial grasses, broadleaf weeds, and woody species.
Glyphosate is applied in a variety of forms: isopropylamine salt, ammonium salt, diammonium salt, dimethylammonium salt, and potassium salt. Thus, it’s important to understand that when glyphosate is applied to crops or weeds, it includes additional adjuvants in the formulation that make it more toxic and thus easier for plants to take up. These glyphosate formulations have also proven toxic to humans. However, companies don’t have to publicly disclose other proprietary chemicals in these herbicide formulations; therefore, regulators and researchers can’t fully study them to determine their health effects.
Glyphosate was originally patented as a chelator and an antibiotic, which means it binds minerals and interferes with microbial systems. These properties have fueled concern that long-term exposure may disrupt nutrient absorption, alter the gut microbiota, and increase antibiotic resistance. The World Health Organization (WHO) has classified glyphosate as a probable carcinogen, and California lists it under Proposition 65 for cancer and reproductive harm.
Because glyphosate is not an intentionally added ingredient, it does not appear on food labels. However, its absence from ingredient panels does not guarantee absence from the product itself. Contamination can occur through agricultural practices, raw material sourcing, manufacturing, transportation, or storage—making independent testing a critical safeguard.
Mamavation Finds Glyphosate in Sourdough Bread
To evaluate potential exposure, Mamavation sent eight sourdough breads to an EPA-certified laboratory for testing. Samples were analyzed for glyphosate using liquid chromatography–mass spectrometry (LC-MS/MS) with a detection limit of 10 parts per billion (ppb), the lowest level routinely achievable in standardized commercial testing. While some academic laboratories may reach lower limits, those methods are not widely available or standardized for consumer product screening.
Here are the main findings:
- 75% of sourdough breads contained detectable glyphosate. That’s 6 out of 8 sourdough breads.
- 67% of USDA organic sourdough breads contained detectable glyphosate. That’s 2 out of 3 USDA organic brands.
- 87% of products had less than 100 ppb glyphosate. Only one product had over 100 ppb glyphosate.
- Most products had less than 40 ppb of glyphosate, which leads us to believe we are dealing with issues related to drift or cross-contamination and not direct application of glyphosate.
Terrence Collins, Teresa Heinz Professor of Green Chemistry & Director of the Institute for Green Sciences at Carnegie Mellon University, had this to say after his scientific review:
“For now, this small-scale testing of sourdough breads underscores how difficult it has become to avoid Glyphosate entirely. I find it encouraging that two of the eight samples showed no detectable levels; if available, I would preferentially choose those brands as a modest way to reward better practices while reducing exposure for my family and others.
At the same time, the findings point to a less appreciated issue. Certain formulations have used Dimethylamine to form glyphosate salts that enhance delivery into plants. Because glyphosate is systemic, a portion can reach the wheat endosperm—the “flesh” of the grain—meaning that even refined white flour may carry low-level residues. This raises the possibility that such formulations could incidentally introduce dimethylamine into the food chain.
Dimethylamine is not itself carcinogenic, but it can form the carcinogenic nitrosamine N-Nitrosodimethylamine under conditions that can arise during food processing. On that basis, the presence of dimethylamine in food-crop supply chains warrants careful evaluation and, where feasible, minimization as a precautionary measure.”
Why Is Glyphosate Found In Bread?
According to the Detox Project, pre-harvest desiccation could be the reason why glyphosate is found in healthy foods, such as bread made from wheat. What is pre-harvest desiccation? This is when glyphosate is sprayed on crops in the late season, just before harvest. The extra spraying of glyphosate helps dry out crops early, thereby shortening the time they are in the field. This saves money and resources for the farmer and food companies, which is why it’s done. But at what cost do consumers pay for early crop drying? Glyphosate has staying power, persists on food, and can be found at higher levels as a result of this practice.
As for organic food products, they’re significantly less likely to contain glyphosate residue; however, it does happen. Henry Rowlands from the Detox Project surmises it’s because of contamination in the supply chain or drift from a nearby field where glyphosate is sprayed. But he also admits that the sourdough process itself could be a factor in the lower amounts and needs further investigation.
“These sourdough results show that the wheat supply in the U.S. is still a focal point for glyphosate contamination. However, it does seem that the levels of this toxic weedkiller are lower in sourdough than in other types of bread, probably because of the fermentation process. Sourdough brands should concentrate on sourcing cleaner raw materials.”
Comparing bread products tested in the past for glyphosate to sourdough bread products tested presently, you also start to see some differences in levels. More studies are needed on various bread products and their differences to make a stronger claim, but it appears that sourdough bread may be lower in glyphosate than other breads. For instance, two whole-wheat products were found to contain over 1,000 ppb of glyphosate in other studies. We did not find anything so high in our small study here. 88% of the sourdough bread products we tested were under 50 ppb.
Can the Sourdough Fermentation Process Lower Glyphosate?
Can the slow fermentation process of sourdough bread lower your exposure to glyphosate? According to a few limited studies, the answer is both yes and no, but ultimately, more studies are needed to verify.
A study published in the journal Applied Microbiology International in 2005 found that 21% of glyphosate degraded within the first hour of fermentation without baking. They did this by adding glyphosate to the dough and monitoring its effects over time. This study was not conducted on sourdough bread, which has a longer fermentation time.
However, there is also contradictory evidence to say the opposite. A more recent study published in the Journal Cereal Chemistry in 2020 found that no change happened. 50% of the total glyphosate resided in the outer 17% of the kernels. In addition, 81% of the total glyphosate in the wheat was found in the bran, shorts, and feeds. This did not change during the fermentation process. Essentially, they found that milling the bread into “white bread” and avoiding whole grains reduced the glyphosate level when tested, likely because that’s where most of the glyphosate is hidden.
Could the process of fermenting sourdough make a difference in decreasing glyphosate? If the first study found some type of degradation of glyphosate within an hour, could it be possible that more glyphosate would degrade because the fermentation time of sourdough ranges from 2-24 hours? This topic hasn’t been studied, so ultimately, we don’t know. We can surmise that it’s possible, but limited.
Our best recommendation, if you cannot find or test for a “clean” sourdough bread, is to start with a glyphosate-free flour, or opt for “white” sourdough bread instead to avoid parts of the plant with higher contamination. We plan on testing flour for glyphosate in the future to help you with breadmaking.
Other Investigations by Mamavation
Mamavation has conducted additional studies looking at glyphosate and other types of contaminants in our food supply. Here are some additional studies you may be interested in for your family:
More Glyphosate Testing
Small Kitchen Appliances
- Water Filters
- Air Fryers & Air Fryer Ovens
- Juicers
- Kitchen Stand Mixers
- Rice Cookers
- Waffle Makers
- Indoor Kitchen Grills & Paninis
- Blenders
- Nut Milk Makers
- Food Processors
- Toasters & Toaster Ovens
- Outdoor Grills & BBQs
- Ice Cream Makers
- Slow Cookers
- Espresso Machines & Mokas
- Electric Kettles
Mamavation’s Investigation of Sourdough Bread Details
Eight sourdough products were purchased via Amazon and Instacart in March 2026. Each product was recorded in our database, pictures were taken, and then sent directly to an EPA-certified laboratory within its original packaging. After the results were given, we spent some time analyzing the data to determine where to rank each product.
We decided upon the following for each category based on advice from our scientific team:
- Not Our Favorite Category: These sourdough bread brands were sent to an EPA-certified laboratory and found to contain glyphosate.
- Better Category: These sourdough bread brands had non-detectable glyphosate results, but are not organic.
- Best Category: These sourdough bread brands are USDA organic and had non-detect glyphosate results.
Product Brands We Tested
To help you make informed decisions about which sourdough bread products are safest for your home, we sent a range of popular sourdough bread brands to our EPA-certified laboratory for testing. Each product was evaluated for glyphosate contamination. Below is the complete list of brands included in our investigation. To see the results for each brand, you’ll need to sign in to or apply to MAMAGATE below.
Brands Tested by Mamavation
- 365 by Whole Foods Market Organic Artisan Sourdough Bread
- Izzio San Francisco Style Sourdough Bread
- Nature’s Own Perfectly Crafted Thick Sliced Sourdough
- Rudi’s Bakery Organic Mountain Sourdough Bread
- San Francisco International Extra Sourdough Bread
- San Luis Sourdough Bread
- Sprouts Organic San Francisco Style Sourdough Bread
- The Rustik Oven Sourdough Bread
Want to see the full laboratory results, detailed contamination levels, and our recommendations for the safest sourdough bread brands? Sign up for MAMAGATE below and get Free Access
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