Lead Safe Mama Food Test Results — What They Don't Tell You About Lead in Food

Tamara Rubin's Lead Safe Mama publishes a lot of food lead test results. The data is real. The interpretation framework is incomplete in a way that consistently overstates risk to readers. Here's what's missing.

How Lead Safe Mama reports results

Lead Safe Mama publishes results in parts per billion (PPB) of lead in the food product. She tends to flag any detection above 5 PPB as worthy of concern. The framing emphasizes presence of lead at the PPB level rather than the µg-of-lead dose per serving.

This is the same problem I covered in my how to determine how much lead you're eating post: PPB is a concentration; it is not an exposure. Two products at the same PPB can produce very different real-world exposures depending on serving size and consumption frequency.

The dose math she leaves out

The simple conversion:

Actual LEAD Dose (µg) = PPB × grams per serving ÷ 1000

Worked example using her own typical reporting framing — a 100-gram serving at 10 PPB lead:

10 × 100 ÷ 1000 = 1 µg of lead

The FDA's Interim Reference Level (IRL) for children is 2.2 µg/day. So the alarming "10 PPB" headline corresponds to an exposure that is less than half the FDA daily limit for a child from that single serving. For an adult woman of childbearing age (FDA IRL 8.8 µg/day), it's about 11% of the daily limit.

FDA action levels for context

The FDA's Closer to Zero initiative sets action levels for baby and young child foods:

  • 10 PPB for fruits, vegetables (excluding root), mixtures, yogurts, custards, single-ingredient meats
  • 20 PPB for single-ingredient root vegetables (carrots, sweet potatoes — soil uptake is unavoidable) and dry infant cereals

Industry compliance is approximately 97% for standard produce, 88% for root vegetables, and 91% for infant cereals.

How dietary intake translates to blood lead

Per the established pharmacokinetics:

  • Each 1 µg/day of dietary lead → approximately +0.16 µg/dL blood lead in children
  • Each 1 µg/day → approximately +0.04 µg/dL in adults

So a child consuming 5 µg/day of lead (above the FDA IRL) would show roughly 0.8 µg/dL elevated blood lead. The CDC's current Blood Lead Reference Value is 3.5 µg/dL.

Vintage Pyrex bowl with Fluoro-Spec perovskite fluorescence — household lead source where surface PPM levels are vastly higher than the PPB-level dietary lead under discussion

Why this framing matters for her business

Reporting PPB without dose conversion produces dramatic headlines. Dramatic headlines drive consultations and home-visit bookings (LSM's reported per-visit fee is around $5,000) and per-product lab tests (her reported $480 per product, based on $80 lab work). The framework is internally consistent with a business that monetizes alarm.

I disagree with that approach on the merits. Lead in food is a real public-health issue, but the appropriate intervention is targeted prevention informed by dose math, not blanket alarm based on PPB headlines. The FDA's Closer to Zero initiative, the WHO/JECFA work, and the Lanphear cohort analysis all give us actual dose-response data to work from.

What to actually do

  1. If you see a PPB number for a food, compute the µg per serving: PPB × grams per serving ÷ 1000.
  2. Compare to the FDA IRL: 2.2 µg/day for children, 8.8 µg/day for women of childbearing age.
  3. If a single serving is a meaningful fraction of the IRL, that food deserves a hard look. If it's a tiny fraction, don't redesign your child's diet around it.
  4. For PPM-level surface lead in your home (paint, ceramics, glazes), use a chemical test like Detect Lead's sodium-rhodizonate swabs or Fluoro-Spec's perovskite reagent — they catch the actual high-concentration sources, which dwarf typical food PPB exposures.

Key facts

  • Lead Safe Mama framing: reports food test results in PPB, flags above ~5 PPB as concerning
  • FDA IRL (children): 2.2 µg/day
  • FDA IRL (women of childbearing age): 8.8 µg/day
  • FDA Closer to Zero baby food action levels: 10 PPB most foods; 20 PPB root vegetables and dry infant cereals
  • 10 PPB × 100 g serving = 1 µg lead = less than half the FDA IRL
  • WHO PTWI: withdrawn 2010 — no safe threshold identifiable

FAQ

How does Lead Safe Mama report food lead test results?

In PPB concentrations, with above 5 PPB flagged as concerning. Without converting to µg per serving (the actual exposure number).

What does the FDA consider a meaningful daily lead dose?

2.2 µg/day for children, 8.8 µg/day for women of childbearing age (Interim Reference Levels).

How do I convert PPB into actual exposure?

µg = PPB × grams per serving ÷ 1000.

Is there a "safe" level of lead in food?

No — but modern dietary intake is well below the deprecated WHO PTWI and well below the FDA IRL.

References

  1. U.S. FDA, "Closer to Zero" Action Plan and Interim Reference Levels (2022)
  2. U.S. FDA Total Diet Study, 2014–2019 (~7,000 lead-specific tests)
  3. EFSA Panel on Contaminants, Scientific Opinion on Lead in Food (2013)
  4. Lanphear, B. P. et al. "Low-level environmental lead exposure and children's intellectual function: an international pooled analysis." Environmental Health Perspectives 113(7): 894–899 (2005)
  5. WHO/JECFA, withdrawal of Provisional Tolerable Weekly Intake for lead, 2010