The U.S. Food and Drug Administration (FDA) has published the results of its “largest and most rigorous” chemical contamination testing assignment for infant formula on the market. The overwhelming majority of samples had undetectable or very low levels of the analyzed substances.

A limited number of human donor breast milk samples were also tested for some contaminants.

The sampling and testing assignment was conducted under the Operation Stork Speed initiative and in alignment with the Closer to Zero initiative.

‘Infant Formula in the U.S. is a Safe Option’

The levels of toxic heavy metals (arsenic, cadmium, lead, and mercury) detected in some samples were well below U.S. Environmental Protection Agency (EPA) drinking water limits for these contaminants. Small amounts of contaminants may be present in foods—including infant formula and breast milk—because they occur naturally or enter the environment through human activities in the areas where ingredients are grown or produced.

“As a father, I understand how important it is for parents to trust the safety of the food they give their children,” said Kyle Diamantas, J.D., FDA for Deputy Commissioner for Food. “This testing … reinforces that infant formula in the U.S. is a safe option for parents and caregivers who rely on it. [FDA] will continue working to drive contaminants to as low as possible through rigorous oversight.”

Low Levels of Contaminants in Some Infant Formulas

A total of 312 samples across 16 brands were tested, with multiple lots tested per brand. The samples comprised 278 powdered formulas, 11 concentrated liquids, and 23 ready-to-feed products; including 258 cow’s milk-based, 44 soy-based, and ten amino acid-based formulas.

FDA tested the samples for arsenic, cadmium, lead, mercury, 30 per- and polyfluoroalkyl substances (PFAS), 318 pesticides, 21 phthalates, and one non-phthalate plasticizer.

The agency found:

• Mercury was not detected in 296 out of 312 samples (95 percent). Among all samples, concentrations ranged from not detected to 0.3 ppb parts-per-billion (ppb). Given the high number of non-detects, a 95^th percentile value and median were not calculated. All samples were at least six times below EPA drinking water requirements for mercury (2 ppb).
• Cadmium was not detected in 106 out of 312 samples (34 percent). Among all samples, concentrations ranged from not detected to 1.5 ppb. Of all samples, 95 percent had less than 1.1 ppb of cadmium. The median cadmium concentration was 0.2 ppb. All samples were at least three times below EPA drinking water requirements for cadmium (5 ppb).
• Lead was not detected in 61 out of 312 samples (20 percent). Among all samples, concentrations ranged from not detected to 1.1 ppb, with 95 percent of samples containing less than 0.5 ppb of lead. The median lead concentration was 0.2 ppb. All samples were at least eight times below the EPA drinking water requirements for lead (10 ppb).
• Arsenic was not detected in 18 out of 312 samples (6 percent). Among all samples, concentrations ranged from not detected to 4.7 ppb. 95 percent of all samples had less than 2.0 ppb of arsenic. The median arsenic concentration was 0.5 ppb. All samples were at least two times below the EPA drinking water requirements for arsenic (10 ppb). Testing of a subset of samples showed that arsenic, when present, was in its inorganic form.
• Pesticides were not detected in 309 of 312 samples (99 percent), and glyphosate and glufosinate were not detected in any samples. Given the high number of non-detects, a 95th percentile and median were not calculated. Only three samples had detectable pesticide levels, all at very low concentrations: 0.25 ppb chlorpyrifos in one sample, 0.20 ppb malathion in a second sample, and 0.20 ppb piperonyl butoxide in a third sample.
• Most PFAS compounds (25 of 30 analyzed) were not found in any samples. The five detected PFAS were present in a subset of samples at concentrations ranging from 0.51 ppt to 150 ppt, depending on the compound. The most frequently detected PFAS was Perfluorooctanesulfonic acid (PFOS), found in half of samples at detectable concentrations ranging from 0.51 to 6.0 ppt, with 95 percent of all samples containing less than 2.9 ppt of PFOS. Given the high number of non-detects, the median was not calculated.
• Phthalates were not detected in 167 out of 312 samples (54 percent). Of the 21 phthalates and one non-phthalate plasticizer tested: seven were not detected in any samples, five were rarely detected (in less than 2 percent of samples), and the remaining compounds that were detected had concentrations ranging from undetected to 145 ppb. The most frequently detected phthalate compounds were DEHP—not detected in 253 out of 312 samples (81 percent), and present at levels up to 57 ppb—and DINP—not detected in 260 samples (83 percent), present at levels up to 145 ppb. Given the high number of non-detects, a 95^th percentile and median were not calculated for either compound.

Toxic Heavy Metals Found in Most Human Donor Milk Samples

FDA also tested a limited number (110) of human milk samples from a single state donor human milk bank for arsenic, cadmium, mercury, and lead. Overall, the majority of samples (85 percent) had at least one detectable contaminant, while 17 samples (15 percent) had no detects of any of the contaminants. Mercury demonstrated the highest detection rate at 61 percent, followed by cadmium at 57 percent, arsenic at 33 percent, and lead at 30 percent.

The results from this limited testing cannot be generalized more broadly to all human milk, however.