The US sulfite declaration threshold is not a zero-content promise
Keep the 10 ppm sulfite threshold attached to its specific labeling conditions rather than treating it as a universal omission or safety rule.
An ingredient list without a sulfite entry is not a laboratory report showing zero sulfite. To understand a commonly cited US threshold, keep the whole labeling provision together: the substance was added, it has no technical effect in the finished food, and its amount is assessed under the rule.
Read the threshold in its own provision
21 CFR 101.100(a)(3)–(4) addresses exemptions for incidental additives and a specific condition for sulfiting agents. For an added sulfiting agent with no technical effect in the finished food, the rule treats its amount as insignificant for this exemption only when no detectable amount is present.
The provision defines a detectable amount as 10 parts per million, or 10 mg/kg, or more of sulfite in the finished food. It also specifies analytical methods for determining compliance. This is not a universal rule allowing every ingredient below 10 ppm to disappear from an ingredient list.
Test the boundary with explicit assumptions
Consider two fictional laboratory records. In both examples, assume the agent was added to the food or one of its ingredients and has no technical effect in the finished food. The numbers are invented for practice, not measurements from a real package.
| Reported finished-food sulfite | Relationship to this threshold | What remains outside the example |
|---|---|---|
| 9 mg/kg | Below the provision's 10 mg/kg detectable-amount boundary | Other labeling requirements and actual product evidence |
| 10 mg/kg | At the boundary; the rule includes this amount | Any personal sensitivity or suitability decision |
The threshold refers to concentration in the finished food. Do not replace that basis with milligrams per serving or the amount in one ingredient without a supported conversion and the necessary data.
The technical-effect condition matters
Now change the scenario: the substance has a preservation function in the finished food. A result below 10 mg/kg alone would not establish eligibility for the no-technical-effect exception described above. You cannot keep the attractive numerical part of a rule while dropping the condition that makes it relevant.
For a real grocery note, record the exact declared name and any stated function. If no concentration evidence is supplied, mark it unknown. Ingredient order, a missing line or an OCR result cannot generate an analytical concentration.
This guide concerns the cited FDA-regulated US food provision. It does not establish rules for every alcoholic beverage or another country, and the threshold is not an individual tolerance or safety recommendation.
For faithful label reading, explore Ingredi AI via the official Apple listing or official Google Play listing. Preserve unknown fields and check the package. A scan does not detect sulfite chemically or determine whether a food is suitable for someone with a sensitivity.