Food Contact Safety for Glassware: Migration Testing, Lead and Cadmium Requirements

A clear glass storage jar and a coloured, decorated drinking glass are both “glassware.” They do not require the same food safety testing. A migration test report issued for one configuration does not automatically cover the other, and no single phrase such as “food grade” or “FDA approved” can substitute for matching the test evidence to the actual product being shipped.

This is the part of glassware sourcing where assumptions become expensive. Buyers assume that a test report on file covers every order from the same factory. Suppliers assume that “passed” on a certificate cover page is enough. Neither assumption survives contact with a customs inspection, a retailer’s compliance review, or a field failure.

What follows is a practical framework for understanding what food contact safety means for glassware, which tests apply to which products, and how to read a test report so that it actually tells you something useful about the glass your customer will receive.

For the full picture on factory audits, testing standards, and how food safety compliance fits into supplier verification, read the pillar guide: The Glassware Importer’s Guide to Factory Audits, Testing Standards and Food Safety Compliance .

What Is a “Food Contact Material” — and Does Glass Always Count?

Under EU Framework Regulation (EC) No 1935/2004 , food contact materials are defined as materials and articles which, in their finished state, are intended to be brought into contact with foodstuffs or with water intended for human consumption. Glass is explicitly listed as one of the material groups covered by the regulation.

In the United States, the FDA regulates food-contact substances under the Federal Food, Drug, and Cosmetic Act. Glass used for food contact is generally recognised as safe based on its long history of safe use, but specific limits apply to lead and cadmium that can leach from the glass surface or from decorations applied to it.

The practical question for a buyer is not “is glass a food contact material?” It is: which parts of this product actually contact food, and under what conditions?

A plain glass tumbler used for cold beverages contacts food only at the interior surface and the lip. A glass storage jar with a bamboo lid and silicone gasket contacts food at the glass interior, the underside of the lid, and the gasket surface. A coloured, decorated drinking glass with enamel applied to the exterior may contact food at the lip if the decoration extends to the rim. A candle holder does not contact food at all, and food-contact migration testing does not apply.

The scope of testing follows the scope of food contact.

What Is Migration Testing — and Why Does It Matter for Glass?

Migration testing measures the amount of a substance that transfers from a material into food or a food simulant under defined conditions. For glassware, the substances of primary concern are lead (Pb) and cadmium (Cd). These heavy metals can be present in glass raw materials, in coloured glass formulations, and in decorative enamels or pigments applied to the glass surface.

The standard test method for glass hollowware is defined by ISO 7086-1 , which specifies the release of lead and cadmium from glass hollowware intended for food contact. The test typically involves filling the glass article with a 4% acetic acid solution, allowing it to stand for a defined period (commonly 24 hours at 22 ± 2°C), and then analysing the solution for lead and cadmium using atomic absorption spectrometry or ICP.

For ceramic ware and glass dinnerware, ISO 6486-1 and Part 2 provide the parallel test method and permissible limits.

The critical distinction: migration testing measures release, not content. A glass product may contain lead in its composition but still pass migration testing if the lead is locked into the glass matrix and does not leach under the defined test conditions. Conversely, a product with a relatively low total lead content may fail migration testing if the lead is present in a surface decoration that readily releases into food simulants.

Why Transparent Glass and Decorated Glass Are Not the Same Test Subject

This is where many buyers get caught.

Transparent, undecorated glass — a clear storage jar, a plain drinking glass, a glass bottle — has a relatively simple food-contact surface. The test focuses on the glass body itself. If the glass formulation and the annealing process are controlled, migration testing is usually straightforward.

Coloured or decorated glass introduces additional variables. The colour may be achieved through the glass composition itself (coloured glass) or through a decoration applied to the surface (enamel, paint, printing, or a coloured coating). Each of these introduces different migration risks.

A study published in Science of the Total Environment analysed 72 externally decorated drinking glassware products and detected lead in 139 of 197 distinct colour and decoration regions tested. Lead concentrations ranged from approximately 40 to 400,000 μg/g, with a median of 63,000 μg/g. Cadmium was detected in 133 cases, with concentrations up to 70,000 μg/g. When the lip area of selected positive samples was tested with 4% acetic acid, lead concentrations normalised to internal volume exceeded 0.5 mg/L in all but one case, with three products returning concentrations over 100 mg/L.

The implication is direct: a migration test report for a clear glass jar tells you nothing about whether a coloured, decorated drinking glass from the same factory complies with lead and cadmium limits. The test must cover the decoration, and it must cover the lip area if the decoration extends to the rim.

What Testing Standards Apply in the EU and the US?

The two markets use different regulatory frameworks, and a report that satisfies one does not automatically satisfy the other.

European Union. The overarching framework is Regulation (EC) No 1935/2004 , which requires that food contact materials do not transfer constituents to food in quantities that could endanger human health or cause unacceptable changes in composition, taste, or odour. Glass is not harmonised at EU level in the same way as plastics, so national measures and recognised standards fill the gap. Germany’s LFGB is widely used as a de facto benchmark across European importers. LFGB Sections 30 and 31 cover food-contact articles, including glassware, and require testing for heavy metal leaching as well as sensory testing for odour and taste transfer. The sensory requirement is a distinguishing feature of LFGB that ISO migration standards do not include.

United States. The FDA regulates food-contact glassware through Compliance Policy Guides (CPGs) . CPG Sec. 545.450 addresses leachable lead and cadmium from food-contact surfaces. The FDA’s focus is on lead and cadmium that can migrate from glass, decorations, and lead crystal used to manufacture foodware. For decorated glassware, ASTM C927 provides a specific test method for lead and cadmium extracted from the lip and rim area of glass tumblers decorated with ceramic glass enamels.

California Proposition 65 adds another layer for products sold in California. Lead is listed under Proposition 65 as a chemical known to cause birth defects or reproductive harm, and enforcement actions have targeted leaded crystal glassware and decorated glassware. Buyers selling into California need to confirm that their product either meets the relevant exposure thresholds or carries the required warning.

How Do Food Type, Contact Time, and Temperature Change the Test?

Migration testing is not a single fixed protocol. The test conditions are selected to simulate the intended use of the product.

For glassware, common migration test conditions include:

• 4% acetic acid at 22 ± 2°C for 24 hours — the standard condition for glass hollowware under ISO 7086.

• 4% acetic acid at 70°C for 2 hours — used for products intended for hot-fill or repeated hot contact.

• Water at 100°C for 5 minutes — for products intended for very hot liquids.

The food simulant matters as well. Acetic acid simulates acidic foods (vinegar, citrus, tomato-based products). Water simulates aqueous foods. Ethanol solutions simulate alcoholic or fatty foods. A glass bottle intended for olive oil may require a different simulant and different exposure conditions than a drinking glass intended for water.

The practical implication for buyers: specify the intended use in the test request. A test conducted under cold-fill conditions does not demonstrate compliance for a product that will be used with hot liquids or acidic foods.

How Do You Read a Test Report So That It Actually Tells You Something?

A test report is not a certificate. A certificate is a summary document that often states “passed” without showing the data. A test report shows the sample description, the test method, the measured values, and the conclusion.

When reviewing a report, check these elements:

Sample description. Does the report identify the exact product configuration? Capacity, material, colour, decoration, lid type, and any other variable that affects the food-contact surface. A report that describes “glass jar” without specifying the lid material does not cover a jar sold with a bamboo lid.

Test method. Does the report state the standard used (ISO 7086-1, ASTM C927, LFGB method, etc.) and the test conditions (simulant, temperature, duration)? A report that says “migration test” without specifying the method is not useful for compliance purposes.

Measured values. Does the report show the actual migration results in mg/L or mg/dm², not just a pass/fail statement? Measured values allow you to compare against the applicable limit and assess margin of safety.

Applicable limit. Does the report reference the limit against which the results are judged? For ISO 7086, the limits are defined in the standard. For FDA CPG, the limits are stated in the policy guide. For LFGB, the limits are defined in the German regulation.

Laboratory accreditation. Was the test performed by an accredited laboratory? ISO/IEC 17025 accreditation is the international benchmark for testing competence. Reports from laboratories without accreditation carry less weight in a compliance dispute.

Report validity and configuration match. Does the report describe a product that matches your order? If the report was issued for a clear jar with a metal lid and your order is a coloured jar with a wooden lid, the report does not apply. If the report is several years old and the supplier has changed glass suppliers or decoration processes, the report may no longer represent current production.

A practical verification workflow is to request the full report (not just the cover page), confirm the issuing laboratory and report number, and then compare the sample description against the purchase order specification. If any component of the food-contact surface differs, ask the supplier to explain why the existing report still applies — or request a new test.

Why “Food Grade,” “FDA Approved,” and “Lead-Free” Are Not Enough

These phrases are marketing claims, not compliance evidence.

“Food grade glass” has no standardised definition. It may mean the supplier considers the glass suitable for food contact, but it does not indicate which test was performed, under what conditions, or whether the test covered the full product configuration.

“FDA approved” is misleading for food-contact glassware. The FDA does not “approve” glassware in the way it approves drugs or food additives. The agency sets leachability limits and compliance policy guides, and products are expected to meet those limits. A supplier that claims “FDA approved” should be asked for the specific test report showing compliance with FDA CPG limits.

“Lead-free” refers to the glass composition, not necessarily the decoration. A glass body may be lead-free while the enamel decoration contains lead. The migration test is what matters, not the composition claim.

The accurate question is: which test was performed, on which configuration, under which conditions, and with what measured results?

What KINGSTAR GLASSWARE Provides

At KINGSTAR GLASSWARE, food-contact test documentation is organised by product configuration, not by generic certificate. For food-contact glass products, we provide test reports from accredited laboratories that identify the tested configuration — glass body, lid material, gasket material, and any decoration — and state the test method and measured values against the applicable limit.

We hold FDA and LFGB test documentation for our food-contact glass products, with separate records for glass bodies, metal lids, bamboo lids, and silicone seals where those components form part of the food-contact surface. When a product configuration changes — a new lid material, a new decoration colour, or a new glass supplier — the test documentation is reviewed to confirm whether the existing report still applies or whether retesting is required.

We welcome buyer review of our test reports and can provide the full report documents, not just certificate summaries, so that buyers can verify the sample description, test method, and results against their order specification.

If your compliance review requires a test that we have not yet arranged for a specific configuration, tell us the product and the destination market. We will confirm what we can provide and what may need to be arranged separately.

Ready to review the food-contact documentation for your next order? Reach out to KINGSTAR GLASSWARE. Tell us your product, your target market, and the components that contact food. We will show you exactly what test evidence we hold for that configuration — and what still needs to be tested.

FAQ

What is the difference between migration testing and a food safety certificate?

Migration testing is a laboratory procedure that measures the amount of a substance — typically lead and cadmium — that transfers from glass into a food simulant under defined conditions. A food safety certificate is a summary document that often states “passed” without showing the test method, sample description, or measured values. For procurement purposes, the full test report is more useful than the certificate cover page, because it allows you to verify that the tested configuration matches your order.

Can I use one test report for all glass products from the same factory?

No. A test report is tied to a specific product configuration: capacity, glass material, colour, decoration, lid material, and gasket material. A report for a clear glass jar does not cover a coloured, decorated glass with a bamboo lid, even if both are made by the same factory. The food-contact surface and the migration risk are different. Each distinct configuration requires its own test evidence, or a documented justification that the existing report still applies.

What should I check on a glassware migration test report before accepting it?

Check the sample description and confirm it matches your order configuration. Check the test method and conditions — standard, simulant, temperature, duration. Check that measured values are reported against the applicable limit. Verify the laboratory’s accreditation. Check the report date and whether the product configuration has changed since the report was issued. If the report describes a different lid, a different decoration, or a different glass colour, ask the supplier to explain why it still applies to your order.

Do I need both FDA and LFGB testing for the same product?

Not necessarily, but the two are not interchangeable. FDA testing addresses US requirements for leachable lead and cadmium. LFGB testing addresses German and broader European requirements, and includes a sensory test that FDA does not require. If you sell into both markets, you may need evidence that satisfies both frameworks. A single test report conducted under one framework does not automatically demonstrate compliance with the other.

Related Articles

Looking for clearer guidance on food-contact safety, migration testing, and heavy-metal limits? Here are three practical pieces from our blog that approach the topic from complementary angles:

• Glassware Importer’s Compliance Roadmap
  Overview of FDA, LFGB, REACH and related frameworks that directly cover migration and restricted substances for glassware.

• Common Quality Issues in Glassware
  The most frequent material and surface problems that can lead to failed migration or heavy-metal tests — and how to catch them early.

• EU PPWR Compliance Guide for Glassware
  How European packaging and material regulations intersect with food-contact safety requirements for importers selling into the EU.