Microbiological Limits Your CPSR Must Prove for the EU

The Cosmetic Product Safety Report gets treated like a paperwork formality by a lot of first-time EU sellers, right up until their safety assessor asks for microbial test data they don't have. Under Regulation (EC) No 1223/2009, that CPSR isn't optional and it isn't just a formula summary. It's a document a qualified safety assessor has to actually sign, and microbiological quality is one of the concrete things they need evidence for, not just an opinion on.

Where microbial evidence sits in the CPSR

The CPSR is built in two parts. Part A gathers the safety information, including the product's microbiological quality. Part B is the assessor's actual conclusion and reasoning, built on top of what Part A supplies. If Part A is missing solid microbial data, the assessor has nothing credible to base a safety conclusion on, and a CPSR signed without that backing isn't doing its job even if it technically exists as a document.

What "microbiological quality" actually means here

This isn't a vague concept. The reference point most assessors work against is ISO 17516, which sets microbial limit standards for cosmetics, essentially defining acceptable levels of microorganisms in a finished product depending on its use category (things like eye area products, products for children, or general use products tend to carry different scrutiny). The assessor needs to see evidence the finished product falls within those limits, not just an assumption that it probably does because the ingredients seemed fine individually.

The two pieces of evidence that usually matter most

• A challenge test (preservative efficacy test). This is where a lab deliberately introduces a panel of representative microorganisms, bacteria, yeast, and mold, into your finished product and tracks whether your preservative system knocks them down over a defined period. A pass here is strong, direct evidence that your formula can control microbial growth under real conditions, not just in theory.
• Microbial count testing on the finished product itself. This measures what's actually present in the product as manufactured, catching contamination introduced during production rather than testing the preservative system's theoretical capability.

Together these answer two different questions: can the formula fight off a microbial challenge, and is the product clean as made. An assessor generally wants both, not one substituting for the other, especially for products aimed at eye contact, mucous membranes, or young children, where the risk tolerance is lower.

Why this is where formulators get surprised

A lot of small brands assume that because they used a "proven" preservative at a textbook percentage, the microbial question is settled. It isn't, for a few reasons:

1. pH interactions matter. Several common preservatives, potassium sorbate and sodium benzoate among them, only work effectively within a certain pH range. A perfectly reasonable percentage in a formula sitting at the wrong pH can still fail a challenge test.
2. Packaging affects real-world contamination risk. A jar that gets fingers dipped into it repeatedly has different microbial exposure than an airless pump, and this can influence what evidence an assessor considers sufficient.
3. Water-based formulas carry more risk than anhydrous ones. Products with little or no water activity generally face a lower microbial burden, but "low water" isn't the same as "no water," and assessors will still want to see the reasoning documented rather than assumed.

Practical steps before you approach an assessor

1. Get a challenge test done through an accredited lab before you expect a CPSR sign-off, not after the assessor asks for it.
2. Document your preservative system's pH dependency so the assessor can see you understood the mechanism, not just picked a percentage off a supplier data sheet.
3. Keep your Product Information File organized so the microbial data sits alongside the rest of your safety documentation, ready for the assessor and available if a market surveillance authority ever asks.
4. Confirm current ISO 17516 category thresholds directly, since the exact microbial limits vary by product use category and it's the kind of detail worth checking against the current standard rather than assuming from memory.

Cosmetic Comply's Canadian ingredient matching and Hotlist screening won't replace an EU safety assessor's microbial sign-off, since that's a distinct piece of the EU's own regulatory framework, but if you're building out the ingredient side of your documentation before EU support goes live, having clean INCI names, CAS numbers, and real finished-product concentrations already organized makes handing things off to a safety assessor considerably less painful.