My diet:

E451 Triphosphates (STPP)

E451Acidity regulatorsOrigin: Mineral
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The short answer
Triphosphates (E451), often sodium tripolyphosphate, make shrimp, scallops and deli meat hold water. They are legal, and they count toward the phosphate limit EFSA says some people already overshoot.
Use in moderation

Safe in small amounts; may bother some people or raise blood sugar.

E-numberE451
Comes fromMineral
What it doesAcidity regulators
Glycemic index—
Daily limit40 mg/kg
Also calledTriphosphates, Sodium tripolyphosphate

Rules by country

🇺🇸 US FDAApproved
🇪🇺 European UnionApproved with limits
🇨🇦 Health CanadaApproved with limits
CaliforniaNo extra rules

Triphosphates are GRAS in the US and widely used to hold water in seafood and meat. In 2019 EFSA set one group limit for added phosphates of 40 mg of phosphorus per kg of body weight a day, and said some children and heavy processed-food eaters can exceed it.

How much is too much? (Acceptable Daily Intake)

2.8 gper day is the safe upper limit

Based on 40 mg per kg of body weight (EFSA / JECFA). A 20 kg (44 lb) child: 800 mg a day.

What is it?

The chain binds minerals and muscle proteins so seafood stays plump after freezing. That is useful, and it is also how a product can weigh more from added water. The phosphorus is the part the daily limit measures.

Where it comes from: Sodium tripolyphosphate is made by heating phosphoric acid salts derived from phosphate rock. It is a chain of three phosphate units, different from the single phosphates (E339) and the diphosphates (E450).

Why it’s in food

  • Plumps frozen shrimp
  • Holds water in deli meat
  • Emulsifies processed cheese
  • Stabilizes whipped mixes

Often found in

Frozen shrimpScallopsDeli meatProcessed cheeseCake mixesFish fillets

Also listed as: Triphosphates, Sodium tripolyphosphate, STPP, Pentasodium triphosphate

Health & gut impact

Phosphate loadUnder study

STPP adds to the same phosphorus budget as the other phosphate additives. EFSA warned that high consumers can pass 40 mg per kg a day.

EFSA re-evaluation of phosphates (2019)

KidneysConcern

People with kidney disease are often told to limit phosphate additives because failing kidneys cannot clear the extra phosphorus.

NKF guidance on phosphorus additives

What can I use instead?

Sodium phosphates, still a phosphate

Ratio: Not a way to avoid phosphorus

Best for: A different chain length

Unprocessed fish and meat

Ratio: Skip the soak

Best for: No added water

Related

More acidity regulators:

Acetic acid E260Acetic acid (E260) is the acid that makes vinegar sour. Diluted in food it is considered safe. The hazard is the concentrated factory form, not a splash of vinegar.Generally safeCalcium carbonate E170Calcium carbonate (E170) is ground limestone, the same calcium found in antacids. It adds calcium to plant milks and flour and is very safe.Generally safeCalcium chloride E509Calcium chloride (E509) is a salty calcium salt that firms tofu, cheese curds and pickles. It is considered safe at food doses. Too much tastes bitter, which is why recipes use a little.Generally safeCalcium citrates E333Calcium citrates (E333) are a calcium salt of citric acid. Food makers use them to firm produce and buffer acidity, and the same salt is a common calcium supplement. They are considered safe.Generally safe

Common questions

Why does frozen shrimp list sodium tripolyphosphate?

The soak helps the shrimp keep moisture in the freezer. It also adds weight and phosphorus. Shrimp without STPP is sold too, usually at a higher price for the same drained weight.

Is Triphosphates safe?

Use in moderation (62/100). Triphosphates are GRAS in the US and widely used to hold water in seafood and meat. In 2019 EFSA set one group limit for added phosphates of 40 mg of phosphorus per kg of body weight a day, and said some children and heavy processed-food eaters can exceed it.

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Scientific sources & regulatory citations
  • 21 CFR 182.1810 (US FDA)
  • EFSA OpenFoodTox: E451
  • EFSA re-evaluation of phosphates (2019)
  • NKF guidance on phosphorus additives

INS 451 · CAS 7758-29-4