Worth knowing · Sulfite preservative

Sulfite preservatives

Also appears on labels as: sodium metabisulfite (used as a preservative), sodium metabisulfite, sodium sulfite

Sulfite salts, such as sodium metabisulfite and sodium sulfite, used as preservatives and antioxidants.

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Where it comes from: Chemical manufacturing.
Why it's in the product: Keeps baked treats and biscuits from spoiling or discoloring, and preserves some cleaners.
Safety and toxicity: Sulfites destroy thiamine (vitamin B1), and sulfite-preserved meat has caused thiamine deficiency in dogs. That is why sulfites are not allowed in meat intended to supply thiamine.
Interactions and who should be careful: Not the same chemical as sodium nitrite, the curing salt, though the two are easy to confuse on a label.

General reference, not veterinary advice. Dose, breed, and existing conditions change the answer, so talk to your vet before changing what your pet eats. Think we got this wrong? Tell us and we log it publicly.