Passing FDA 21 CFR 177.2600 and LFGB Silicone Tests

If you're quoting food-contact silicone, 21 CFR 177.2600 does not certify a drum of gum.

It is a US regulation for rubber articles intended for repeated use in food contact. You pass or fail as a finished article (the tray, the gasket, the mold face that will touch chocolate), extracted in defined solvents at reflux, against numeric ceilings. LFGB is not a stricter reprint of the same flask. It is Germany's food-contact law, applied to silicone largely through BfR Recommendation XV, with simulants and a sensory test. Dual-market programs run both. They do not nest.

Platinum addition-cure (LSR, platinum HCR, some platinum RTV prototype molds) is the realistic chemistry. Post-cure is part of the specimen. Tin-cure RTV is the wrong start. An industrial translucent leftover is the wrong start.

A gum drum is not a 177.2600 certificate

Buyers treat “platinum-cured food grade” on a website as the spec, then file a spatula-line certificate against a chocolate mold. Color and Shore A are not tests. Paying a tooling charge on a cover photo does not tell you which article was extracted. Don't call the LSR stack a “LIM hot tool.”

Which article actually goes in the flask

Say you need a 180 × 120 mm baking tray, Shore 50A, 250 first articles and about 20,000 a year, US and German retail, oven and dishwasher claimed.

For the 250, a shop may run an aluminum one-cavity HCR tool. An RTV prototype mold checks geometry only-it does not qualify food contact.

For a few thousand millable trays, you'll usually cut a heated two-plate HCR tool. Platinum HCR with a ventilated post-cure is the realistic dual-market path; peroxide HCR is the harder sensory route. Typical shrink ~1.5-2.5%.

If annual volume justifies LSR, the production tool needs cavity heat, gates, vents, and usually a cold-runner. Typical shrink ~2-3%. Those three PDFs can all say “FDA mold.” You're not buying the same specimen.

Extraction questions before you buy the test

Before you compare prices, get answers on:

• Markets: US / DE-EU / both; food types and use temperature (oven, boiling, freezer, dishwasher if claimed)?
• Process: HCR compression vs LSR injection (cold-runner vs dump-runner); platinum vs peroxide; post-cure T/t/thickness?
• Test report on the finished article from the production process-not a raw-gum statement?
• Who owns the plates and inserts after the tooling charge, and can you move the tool?
• first-article inspection (FAI) against a ballooned print, including ISO 3302-1 (M2 is a common default)?

If those lines are missing, the cheaper quote is usually the incomplete one.

The regulation tests the article, not the marketing name

177.2600 sets composition constraints for rubber (including silicone as described in the section) and then says, in substance: the food-contact surface of the article in the finished form shall meet extraction limits. Dry-food use is framed as suitability under GMP. Aqueous and fatty uses get the flasks.

The section also expects finished rubber articles to be thoroughly cleansed before food contact. That is a process instruction, not a slogan. Mold release, trim dust, and post-cure bloom are your problem.

EU and German buyers will also point at Regulation (EC) 1935/2004. LFGB is how Germany polices that. BfR XV is the silicone-specific recommendation labs actually methodize.

Water and n-hexane extractables under 177.2600

For repeated-use rubber in contact with aqueous food, extract the food-contact surface with distilled water at reflux:

• First 7 hours: total extractives not to exceed 20 milligrams per square inch
• Succeeding 2 hours: not to exceed 1 milligram per square inch

For fatty foods, extract with n-hexane at reflux:

• First 7 hours: not to exceed 175 milligrams per square inch
• Succeeding 2 hours: not to exceed 4 milligrams per square inch

Those numbers are the regulation. They are not a vendor's marketing limit. Surface area of the article as used matters. A thick slab and a thin nipple are different specimens even in the same compound if post-cure and surface-to-volume differ.

Composition lists in 177.2600 still matter. You cannot pass extraction on a cocktail of unlisted ingredients and call it good. Work with a compounder who formulates inside the section, then test the article.

BfR XV simulants and the LFGB sensory check

A typical German/EU silicone kitchenware stack (confirm the current BfR XV and the lab's method) includes:

• Composition / positive-list thinking for silicones
• Volatile organic matter (a tight volatiles limit is a common reason under-baked parts fail)
• Migration or extractables against simulants matched to use: water, 3% acetic acid, and 95% ethanol are the usual silicone set, at time and temperature that represent hot-fill, boiling, or oven use as claimed
• Organoleptic / sensory: the article must not impart smell or taste

Sensory is why a peroxide HCR that squeaks through a US hexane flask can still fail LFGB: odor. Platinum LSR with a proper post-cure is the usual dual-market path for consumer ware. It is not automatic. Pigments, oils, and a short bake fail both systems in different ways.

LFGB is not FDA plus 20 percent. Aqueous acetic acid and ethanol simulants plus smell catch things n-hexane reflux does not, and vice versa. PAHs, specific metals, or other add-on screens appear when the lab or the buyer writes them. Put the use-case on the quote or you will buy the widest, slowest scope.

Post-cure defines the test specimen

The article you test must be the article you sell.

• Cure chemistry: platinum addition-cure for most food-contact molding. Peroxide HCR only with a post-cure that actually clears volatiles and odor. Tin-cure RTV is not the program.
• Post-cure: ventilated oven, time scaled to thickness. A 2 mm LSR spatula and a 15 mm baking mold do not share a bake. Skip post-cure and you are testing a different, dirtier article. Cyclics and catalyst residues are what flasks and sensory panels find.
• Cleaning: wash as production will wash, because 177.2600 expects a cleansed article.
• Pigment freeze: requalify if color changes.
• Process identity: injection LSR plaque does not automatically qualify a compression HCR tray. A test on natural gum does not qualify a red part.

For a food-contact mold (chocolate, cake, ice), the mold is the article. A certificate on the factory's spatula line does not cover that mold. For a mold used only to cast non-food resin, food testing is the wrong spend.

Refuse a fake SGS report number, a raw-gum statement, and an industrial HCR relabeled because it is the same Shore.

When this article is the wrong quote

If you need a reusable RTV cavity for non-food resin, don't buy 177.2600. If the SKU is a chocolate or cake mold, food-contact still matters-but decide whether that cavity is an HCR/LSR part or a master + box + jacket job. A cheap aluminum one-cavity can beat both a full LSR cold-runner and a large RTV stack when the tray is tiny and annual quantity is only a few hundred. Geometry and what actually ships override the market slogan on the RFQ.

Related reading: industrial vs food-grade, medical ISO 10993 vs USP Class VI, silicone mold tooling explained, LSR vs HCR prototype tooling.

What to send for a food-contact quote

Copy this into the RFQ.

• STEP/STL and 2D with critical dimensions and a rubber tolerance class (often ISO 3302-1 M2)
• Markets: US / DE-EU / both; food types; time and temperature of contact
• What ships: molded silicone part, or a flexible cavity
• Process: LSR / platinum HCR / platinum RTV prototype mold, Shore, color, post-cure to be used in production
• First quantity and annual quantity
• Process preference: HCR compression vs LSR injection (cold-runner vs dump-runner)
• Who should own plates/inserts after the tooling charge
• Explicit: food-contact is not ISO 10993, not USP Class VI, not a color; test after production post-cure

Send the STEP file, the market and food type, annual quantity, and HCR vs LSR preference. That is enough for a plate-stack sketch before anyone mills steel.

Test the finished article, not the drum

Do not fil a spatula-line certificate against this tray, skipping post-cure, or cutting a steel LSR tool with a cold-runner before a 180 × 120 mm tray has run as a one-cavity HCR prototype mold-unless annual volume and automation are already on the PO. Do not switch Shore A to fix a failed flask. Do not treat a tooling charge as ownership.

WYD Prototype → Compression → LSR (use this on the RFQ, then ignore quantity if geometry disagrees):

Route the RFQ from what actually ships: if Reusable RTV cavity, non-food resin, go to an RTV master-and-jacket quote on the WYD quote form; if Food-contact molded part or tray, go to Market, food type, annual qty; if Tens to low hundreds / validation, go to Aluminum one-cavity prototype mold; RTV geometry only; if Thousands, millable platinum HCR, go to HCR compression: mill, preform, flash land, deflash; if Higher annual, LSR grade, automation, go to LSR injection: cavity heat, gates, vents, cold-runner.

Geometry and what actually ships override the process name. A tiny food-contact gasket at 400 pcs/year is still a compression job. A deep undercut at 50,000 pcs still needs side actions no matter which rubber family you pick.

RFQ comparison bands: 180 × 120 mm baking tray

Route	Typical first qty	Hardware	Typical shrink allowance	Typical drawing class
RTV prototype mold / jacket	20-50	Master + box + jacket	Platinum RTV ~0.1-0.3%	Cavity, not a rubber-article class
HCR compression	Low thousands	Two-plate, flash land, platen or cartridge heat	~1.5-2.5%	ISO 3302-1 M2 unless the 2D says M1/M3
LSR + cold-runner	High annual, automation	Steel, cavity heat, gates/vents, cold-runner	~2-3% (grade/temp)	Same drawing class + FAI remeasure

These are shop-normal bands for RFQ comparison, not a named lot.

FAQ

Does 21 CFR 177.2600 certify a drum of gum? No. You pass or fail as a finished article extracted in defined solvents at reflux against numeric ceilings. Platinum-cured food grade on a website, without a method, a food type, and a report on the article, is advertising. Color and Shore A are not tests.

Are LFGB and BfR XV just a stricter reprint of the US flasks? No. They are parallel programs, not nested. US aqueous and fatty uses use distilled water and n-hexane at reflux with the section milligram-per-square-inch ceilings. BfR XV typically adds composition rules, volatile organic matter, simulants such as water, 3% acetic acid, and 95% ethanol, and an organoleptic check.

Why can a peroxide HCR squeak through US hexane and still fail Germany? Sensory. Odor is why a peroxide path is the harder dual-market route. Platinum LSR with a proper post-cure is the usual dual-market path for consumer ware; it is not automatic. Pigments, oils, and a short bake fail both systems in different ways.

Does a certificate on the factory spatula line cover my chocolate mold? No. For a food-contact mold, the mold is the article. A test on natural gum does not qualify a red part, and an injection LSR plaque does not automatically qualify a compression HCR tray. For a mold used only to cast non-food resin, food testing is the wrong spend.

Will switching Shore A fix a failed extraction flask? No. Failing a flask is usually formulation, short post-cure, or testing the wrong specimen. It is not fixed by printing FDA on the carton. Send the lab the finished, post-cured, cleaned part, and the use-case.