Food safety has been at the heart of our mission since the moment we set out to develop the Impossible Burger. This involves screening for contaminants such as pesticides, which we do regularly. For more information about how and why we test for pesticides, and a look at our results, keep reading.
(Spoiler: We tested six lots of Impossible Burger for glyphosate, AMPA and an additional 300+ pesticides. All samples came back “negative.”)
Since early 2017, we’ve been sending samples to Silliker Inc. (Merieux Nutrisciences) — a leading, accredited provider of food, nutrition and safety services, for pesticide testing. To date, we’ve sent them six samples of Impossible Burger to have it tested for glyphosate, the glyphosate metabolite, aminomethylphosphonic acid (AMPA), and more than 300 additional pesticides (including herbicides, insecticides, fungicides, and more). We were particularly interested in the test results for glyphosate and AMPA because we use a GM soy protein derived from glyphosate-resistant soybeans.
How to interpret results
The term “limit of detection” (LOD) is used to describe the smallest amount of the substance being analyzed that can reliably be distinguished from zero. The LODs for glyphosate, AMPA, and all but three of the 300+ additional pesticides are 0.005 parts per million (ppm), 0.01 ppm, and 0.005 ppm, respectively.
How we use the LOD: If no glyphosate is detected by a laboratory test, it’s reported as <0.005 ppm. The assumption is that if 0.005 ppm (or more) of glyphosate is present, it will be detected, but if 0.004 ppm or less is present, the test will not detect it. (A quick note on terminology: test results below the LOD are referred to as “negative,” while results at or above the LOD are referred to as “positive.”)
Three different samples of Impossible Burger made with GM soy protein concentrate and three different samples made with non-GM soy protein concentrate were tested. Each sample was negative for glyphosate, AMPA and all other 300+ pesticides. In each case, glyphosate and AMPA were tested twice to increase the chances of detecting these residues.
Consumption limits and “tolerance levels”
Positive pesticide test results are to be expected from time to time, even with organically grown crops. Since 1990, the United States Department of Agriculture (USDA) has been sampling both conventionally grown and organic crops as part of its Pesticide Data Program (PDP), and systematically testing them for hundreds of pesticides. In 2018, on average, conventionally grown crops had 3.2 pesticide residues detected per sample, and organically grown crops had 0.75 pesticides detected per sample.
The US Environmental Protection Agency (EPA) uses extensive risk assessments to set conservative “tolerance levels” below which they are confident that a given pesticide residue poses no health risk to the consumer. This level generally represents a 100-fold margin of safety from any known effects of the chemical. In other words, a “positive” result doesn’t necessarily pose a health risk. For example, the tolerance level set by the EPA for glyphosate in conventional soybeans is 20,000 parts per billion. A 2016 FDA report examined soybean samples and found that 67% tested positive for glyphosate, but that none (0 of 267) reached the tolerance limit.
Regulatory agencies throughout the world — including the EPA, the Food and Agriculture Organization of the United Nations/World Health Organization (FAO/WHO) and the European Food Safety Authority (EFSA) — have set chronic (daily) consumption limits for glyphosate (These glyphosate limits typically include both glyphosate and AMPA).
The acceptable daily intake (ADI) of glyphosate set by FAO/WHO is 1 mg per kg of body weight. The EPA’s daily limit is 1.75 mg per kg of body weight. The most conservative daily limit was set by EFSA: 0.5 mg per kg of body weight. If we use the conservative limit set by the EFSA as an example, a 100-lb (45 kg) person could safely consume 22.5 mg of glyphosate (22,500 µg of glyphosate) a day, every day, for life. California’s Prop 65 sets “No Significant Risk Levels” (NSRL) for cancer-causing chemicals, and they set a limit for glyphosate of 1100 µg per day, regardless of body weight.
So what does this mean about the Impossible Burger?
If glyphosate were present just below the LOD (i.e., at 0.004 ppm) in the Impossible Burger, a person could consume over 2400 4-ounce patties a day — every day, for life — and still be below CA Prop 65’s NSRL. If AMPA was present just below its LOD (i.e., at 0.009 ppm), a person could consume over 1000 4-ounce patties per day, every day, for life, and still be below CA Prop 65’s NSRL.
We’ve always been transparent about our ingredients and our methods because consumers deserve to feel well-informed and safe about their decision to eat Impossible. We also welcome your questions at [email protected]
Dr. Sue Klapholz, M.D., Ph.D, is VP of Nutrition and Health at Impossible Foods. Before joining Impossible Foods in 2013, Sue was a senior scientist at Cell Genesys, where she established a large DNA cloning lab and led the team that cloned the megabase-sized human immunoglobulin genes in yeast, among other projects. Sue also taught a professional course in cloning and analysis of large DNA molecules at Cold Spring Harbor Laboratory, NY, and was a lecturer on genetics and evolution at The University of Chicago. Sue was a resident physician in the Department of Psychiatry at The University of California, San Francisco. She was also a postdoctoral fellow in the Department of Biochemistry at Stanford University, where she worked on cloning a gene responsible for manic-depression, and a postdoctoral fellow in the Department of Biology at The University of Chicago, focusing on the genetic control of recombination and chromosome segregation during meiosis in yeast. Sue has an M.D. from The University of Illinois College of Medicine and a Ph.D. in genetics from The University of Chicago.