Methylisothiazolinone
Methylisothiazolinone carries a safety score of 3/5 and appears in 53 indexed US food products.
3/5 from FDA SAFFA + CSPI Chemical Cuisine
How common is vs other flagged additives?
Number of indexed products containing each of the most common flagged additives — Methylisothiazolinone highlighted.
Indexed products containing each flagged additive. Source: Open Food Facts ingredient lists × FDA SAFFA × CSPI Chemical Cuisine.
Safety Assessment
Methylisothiazolinone has a moderate safety profile (3/5). While approved for use, some studies or consumer advocacy groups have raised questions about certain aspects of this ingredient. Consumers who prefer caution may wish to limit intake.
What the Data Says About
Methylisothiazolinone currently appears in 53 products across the OpenFoodFacts catalog we index, which gives a concrete measure of its footprint on US grocery shelves. Our internal safety score of 3/5 synthesizes FDA Substances Added to Food (SAFFA) regulatory status with the Center for Science in the Public Interest (CSPI) Chemical Cuisine classification. These two frameworks capture different questions: regulators ask whether exposure at typical intake is acceptable, while consumer-advocacy groups examine cumulative dietary load and vulnerable-population risk.
Methylisothiazolinone serves one or more technical functions in food manufacturing — stabilization, flavor, preservation, or structural role — which explains its presence across multiple product categories in our database. Inspection and outbreak records frequently trace back to control failures around functional additives, whether through batch contamination, undisclosed substitutions, or labeling mismatches that trigger recall classifications by the FDA.
No specific concern flags are attached to Methylisothiazolinone in our current data snapshot beyond the regulatory and CSPI classifications above. That does not rule out individual sensitivity reactions, and anyone managing allergies, elimination diets, or chronic conditions should verify with a qualified healthcare professional before relying on population-level ratings.
Safety Profile at a Glance
| Source | Classification | Year |
|---|---|---|
| FDA SAFFA | Not listed | 2024 |
| CSPI Chemical Cuisine | Not rated | 2024 |
| PlainFoodSafe Score | 3/5 | 2026 |
| Product footprint | 53 products | OpenFoodFacts |
FDA SAFFA database, CSPI Chemical Cuisine ratings, OpenFoodFacts product index. See methodology.
Products Containing
Showing 50 of 53 products
Frequently Asked Questions
Is Methylisothiazolinone safe to eat? ▼
Methylisothiazolinone has a safety score of 3/5. Always check with a healthcare provider if you have specific dietary concerns.
What products contain Methylisothiazolinone? ▼
Methylisothiazolinone is found in 53 products in our database, spanning various food categories and brands.
What does Methylisothiazolinone do in food? ▼
Methylisothiazolinone serves various technical functions in food manufacturing and processing.
Where does this ingredient safety data come from? ▼
Safety data comes from the FDA's SAFFA (Substances Added to Food) database, CSPI (Center for Science in the Public Interest) ratings, and the OpenFoodFacts product database. Product counts reflect items cataloged in OpenFoodFacts.