Food Anti-Caking Agents — E551, E552 and Which to Use
Direct answer
Choose a food anti-caking agent by what is causing the caking: silicon dioxide (E551) for moisture, calcium silicate (E552) for fat or oil, tricalcium phosphate (E341iii) for dairy and bakery powders.
This page covers food grade agents used in seasonings, powdered beverages, bakery premixes, salt and dairy powders. If you are dosing a mineral premix or compound feed, that is a different regulatory and technical problem — see Feed Anti-Caking Agents.
The common food grade choices are not interchangeable. Silicon dioxide (E551) is the general-purpose moisture scavenger for seasonings and powdered drinks. Calcium silicate (E552) absorbs both moisture and oil, which makes it the choice for fatty or spice-heavy blends. Tricalcium phosphate (E341iii) is used where the calcium itself is acceptable or desirable, often in dairy and bakery powders. Magnesium carbonate (E504) suits salt and table blends. Sodium aluminosilicate (E554) is used in salt and dry mixes where a very low dose is required. The ferrocyanides (E535, E536, E538) are crystal modifiers for salt specifically — they change how salt crystals grow, and they are not general powder flow aids.
Choose in one table
| Your powder and its problem | Use | Not this |
|---|---|---|
| Seasoning or powdered beverage picking up humidity | Silicon dioxide E551 | Ferrocyanides (salt-specific) |
| Spice blend, cheese powder or any blend with free oil | Calcium silicate E552 | E551 alone (saturates) |
| Dairy or bakery powder where added calcium is acceptable | Tricalcium phosphate E341iii | E554 (label sensitivity) |
| Table salt and salt-based blends | Magnesium carbonate E504 | E552 (over-specified) |
| Salt crystal growth and hard-caking in bulk salt | Ferrocyanide E535/E536/E538 | E551 (wrong mechanism) |
| Caking caused only by bulk-bag compaction | Fix packaging and storage first | Any dose increase |
Why the powder is caking
Diagnose before you dose. The three causes behave differently:
- Moisture migration. Hygroscopic ingredients pull ambient humidity, dissolve slightly at the particle surface, and recrystallise as a solid bridge. This is the classic seasoning and powdered beverage failure. Silicon dioxide is the right tool.
- Fat or oil bleed. Spice oleoresins, cheese powder, and fat-containing premixes release free oil that glues particles together. Silicon dioxide alone saturates; calcium silicate, with its higher oil absorption, holds more.
- Compaction. Bulk bag head pressure and vibration in transit consolidate the bed with no moisture involved at all. An anti-caking agent helps only at the margin here — packaging and storage practice matter more.
Typical inclusion
Inclusion is normally in the range of 0.3 to 2 percent depending on the agent, the substrate, and the regulatory limit for the food category. Always confirm the permitted level for your specific product under Canadian food additive regulations before setting a dose; permitted use is by food category, not by a single global limit.
Specification points that change the price
Surface area and particle size drive both performance and cost. A fumed silicon dioxide with high surface area works at a lower dose than a precipitated grade but costs more per kilogram; the cost per tonne of finished blend can go either way. For calcium silicate, ask for the oil absorption figure — it is the number that predicts performance in a fatty blend. For any agent, ask for bulk density, because it determines how the material behaves in your dosing equipment.
What to put on the RFQ
The E-number, the food grade standard (FCC or equivalent), particle size or surface area, bulk density, oil absorption where relevant, packaging, and the documentation set: certificate of analysis, food grade declaration, heavy metals statement, and allergen and GMO status.
Common mistakes
Choosing silicon dioxide for a fatty spice blend and then increasing the dose when it fails, instead of switching to calcium silicate. Using a salt-specific ferrocyanide as a general flow aid. Buying on price per kilogram rather than cost per tonne of finished blend at the dose that actually works.