Heavy metal testing is where an ingredient’s safety stops being a claim and becomes a number. Specifications promise, suppliers reassure, and certifications confirm systems, but only a laboratory result tells you how much lead or cadmium is actually in the lot sitting on your dock. For QA and regulatory teams, understanding how that number is produced, how often to require it, and what to compare it against has become a core competency rather than a specialty topic.
The pressure behind that shift is regulatory and commercial at once. Federal action levels are tightening, state laws are adding testing and disclosure requirements, and retailer specifications keep raising the contractual bar. A manufacturer that treats heavy metals as a box already checked by the supplier is betting its brand on someone else’s program.
At One Source Food Solutions, we support food manufacturers, co-packers, and private label brands whose products face this scrutiny. As the sourcing partner between buyers and processors, we coordinate the contaminant testing and documentation that ingredient purchases increasingly require, including for the elevated standards infant and toddler products carry.
If your team is defining heavy metal testing requirements for an ingredient program, contact One Source Food Solutions to talk through what your product category calls for.
Which Heavy Metals Matter in Food and Where They Come From
Four elements drive nearly all regulatory attention in food: lead, arsenic, cadmium, and mercury, the group regulators refer to as toxic elements. The FDA’s Closer to Zero initiative targets exactly this group, prioritizing foods eaten by babies and young children because the very young are most vulnerable to the health effects of exposure.
None of these metals is an ingredient anyone adds. They occur naturally and as environmental pollutants in air, water, and soil, and they enter food when plants take them up from the ground much the way they take up nutrients. That origin has two practical consequences for a QA program. First, no processing step removes them, so control has to happen through sourcing and verification rather than through the plant. Second, because uptake happens in the field, the numbers on a finished-product certificate reflect decisions made at planting, months before your purchase order existed.
How Heavy Metal Testing Is Actually Performed
The workhorse method of heavy metal analysis is inductively coupled plasma mass spectrometry, or ICP-MS. The FDA’s own laboratory procedures, published in its Elemental Analysis Manual for food, use ICP-MS to determine arsenic, cadmium, lead, mercury, and other elements in a single run, and commercial food laboratories follow the same approach. The sample is digested in acid, introduced into a plasma hot enough to ionize the elements, and measured by mass, which allows quantification down to fractions of a part per billion.
Two details on a lab report deserve more attention than they usually get. The first is accreditation: results carry weight when the laboratory holds ISO/IEC 17025 accreditation for the method, because that accreditation is what makes the number defensible to a regulator or a retailer. The second is the reporting limit. A result of “not detected” means nothing by itself; it means the level was below whatever concentration the lab can reliably report, and that threshold varies between labs and methods. A “not detected” with a reporting limit of 5 ppb tells you far more than one with a limit of 50 ppb, and for a product judged against a 10 ppb action level, the difference decides whether the result is usable at all. QA teams should specify required reporting limits when they commission testing, not discover them on the certificate.
How Often Should Ingredients Be Tested for Heavy Metals?
Frequency is where heavy metal testing programs quietly succeed or fail. The main options form a spectrum: per-lot testing, where every production lot is analyzed before release; skip-lot testing, where a defined fraction of lots is tested once a supplier has built a consistent history; and periodic or annual verification for low-risk ingredients. Each step down the spectrum trades assurance for cost.
Upstream testing is the other frequency lever. The strongest suppliers screen crops, soil, and growing water before harvest rather than relying solely on finished-product results. A supplier that can show upstream data is controlling the hazard where it originates, which in turn is what justifies moving that supplier toward skip-lot status. The documentation side of this arrangement, from testing frequency commitments to archived historical records, is covered in our guide to heavy metal compliance in fruit and vegetable purees.
How to Read Test Results Against FDA Action Levels
A test result only means something against a limit, and the limits are in motion. In January 2025, the FDA finalized action levels for lead in processed foods intended for babies and young children under two: 10 parts per billion for fruits, vegetables, mixtures, yogurts, custards and puddings, and single-ingredient meats, and 20 ppb for single-ingredient root vegetables and dry infant cereals. Action levels are guidance rather than binding limits, but the FDA may treat food exceeding them as adulterated, and buyers and retailers have adopted them as the working benchmark.
Closer to Zero covers arsenic, cadmium, and mercury alongside lead, and action levels for those metals are still to come, so a testing program built only around today’s lead number will need to widen. State law is moving too: California now requires baby food makers to test every lot for all four metals and publish the results, and other states are following the model. For ingredients headed into infant or toddler products, the full set of expectations, and what separates infant grade from standard food grade, is the subject of our post on what makes a tomato puree infant grade.
For everything below the infant threshold, the practical standard is often contractual rather than federal. Retailers and brand owners write their own heavy metal specifications into supplier agreements, sometimes stricter than any regulation, and a QA team needs to test against the tightest limit its products actually face, not the loosest one that legally applies.
How to Build a Heavy Metal Risk Assessment for Your Ingredients
A risk assessment is what turns testing from a flat expense into a targeted control. The goal is a documented ranking of your ingredient list that answers one question per ingredient: how much testing does this one deserve?
Two factors drive the ranking. The first is uptake risk, meaning how readily the crop behind the ingredient accumulates metals from soil and water. Root vegetables, rice, and leafy greens sit at the high end because of how and where they grow; tree fruits generally sit lower; tomatoes and most vine crops fall in between. Growing region matters alongside crop type, since soil composition and historical contamination differ field to field. The second factor is end-use sensitivity: an ingredient destined for an infant puree carries a different testing obligation than the same ingredient going into an adult condiment, because the limits, the scrutiny, and the consequences all differ.
Scoring each ingredient on those two axes produces the testing plan almost automatically. High uptake risk plus sensitive end use earns per-lot testing with tight reporting limits and upstream data. Low uptake risk plus general end use can justify periodic verification. Everything else lands between, and the documented rationale is itself an asset, because it shows an auditor that testing intensity follows analyzed risk rather than habit. Revisit the assessment when regulations move, when a supplier or growing region changes, or when a new product line shifts an ingredient’s end use.
Connect With One Source Food Solutions
The cost of a testing program is easy to read on a laboratory invoice. The cost of the gap it would have caught arrives later and larger, as a rejected shipment, a retailer delisting, or a recall carrying your brand’s name.
At One Source Food Solutions, we help our partners keep that gap closed for the ingredients we source. We work with processors whose testing programs match the sensitivity of your end product, assemble the laboratory results and specifications your reviews depend on, and flag regulatory changes before they reach your requirements.
If heavy metals are on your QA agenda this year, call One Source Food Solutions at (360) 887-9430 or reach out through our contact page. We are here to help you source with confidence.