Methodology

How We Score

Plain Label evaluates every baby food product on two independent dimensions: regulatory compliance and relative purity.

Layer 1: AB 899 Compliance (Pass / Fail)

Every product is checked against the heavy metal limits established under California's AB 899 law:

Metal	AB 899 Limit
Lead (Pb)	50 ppb
Arsenic (As)	100 ppb
Mercury (Hg)	20 ppb
Cadmium (Cd)	50 ppb

If a product's average test result for any metal exceeds its limit, it receives a FAIL status. Otherwise, it receives a PASS. This is a binary, objective assessment.

Layer 2: Purity Rating (☆ to ★★★)

All products currently tracked on Plain Label pass AB 899 limits. But "passing" covers a wide range — a product with 1 ppb of lead and one with 40 ppb both pass, even though one has 40x more.

The Purity Rating compares products against best-in-class benchmarks — what the cleanest products actually achieve — rather than legal maximums.

Purity Benchmarks

Metal	Best-in-Class	AB 899 Limit	Ratio
Lead	0.5 ppb	50 ppb	100x below limit
Arsenic	3.0 ppb	100 ppb	33x below limit
Mercury	~0 ppb	20 ppb	Most products undetectable
Cadmium	1.5 ppb	50 ppb	33x below limit

These benchmarks are derived from the distribution of test results across all 95 products in our database, representing approximately the 30th percentile. For mercury, which is undetectable in approximately 90% of products tested, we use a special scoring method that rewards zero-detection results.

Star Tiers

Rating	Score	Meaning
★★★	90–100	Lowest Detected — Among the cleanest baby foods tested. All metals well below best-in-class benchmarks.
★★☆	70–89	Clean — Consistently low levels. Well below regulatory limits.
★☆☆	50–69	Standard — Within safe range. Some metals moderately above best-in-class benchmarks.
☆☆☆	0–49	Baseline — Passes all regulatory limits but higher than most peers.

Important Context

Every tier is safe. A ☆ Baseline product passes all AB 899 limits. The purity rating reflects relative positioning among safe products, not a safety judgment.
Benchmarks are recalculated as we add more brands and products. A product's star rating may change over time.
Star ratings reflect averages. Individual lot results may vary.

Where Does the Data Come From?

All heavy metal test data comes from manufacturer-published test results. We do not conduct independent testing.

Cerebelly — Test results via Shopify product metaobjects
Pumpkin Tree Snacks — Test results on their product safety page
Plum Organics — Test results in HTML tables on their website

We aggregate, normalize, and display this data to make it comparable across brands. We do not alter or selectively present results.

Limitations

We display only the data that brands choose to publish.
Test methodologies may vary between brands and laboratories.
This site provides informational content only. It is not medical advice.
Plain Label is an independent project, not affiliated with any brand.

Plain Label is an independent informational resource. Nothing on this site constitutes medical, legal, or dietary advice. All heavy metal test data is sourced from manufacturer-published results and presented without alteration. Purity ratings represent our editorial methodology for comparing products within the safe range — they are not regulatory assessments. Product formulations and test results may change at any time. We make reasonable efforts to keep data current but cannot guarantee accuracy. Use this information as one input among many when making decisions about your child's nutrition.