Chemical Connections UK Contract Chemical Manufacturing

Preservatives and biocides control microbial growth within a product, or exert a controlling effect on harmful organisms such as insects, bacteria or algae more broadly. In the UK, biocidal products require authorisation under the UK Biocidal Products Regulation (UK BPR), with active substances requiring prior approval.

Key points

  • Biocidal products must have UK authorisation before being placed on the market, and their active substances must be separately approved.
  • Great Britain has operated its own standalone biocides regime since 1 January 2021, following Brexit.
  • Preservatives for cosmetics specifically must be approved by the Secretary of State following independent scientific advisory review, and added to a permitted list.
  • Some biocidal product types have more specific legislation, such as pesticides, human medicines and veterinary medicines.

How Preservatives Are Used in Manufacturing

Preservatives are typically added at low concentration during aqueous blending or liquid chemical blending, protecting water-based formulations from microbial spoilage over their shelf life.

Regulatory Considerations

Any biocidal claim - such as disinfection or preservation - generally brings a product within scope of UK BPR, requiring both product authorisation and prior approval of the specific active substance used. This applies across cleaning chemicals and many other water-based formulated products. Confirm with a prospective manufacturer how they verify the regulatory status of preservative systems used in your formulation.

Preservation Versus Biocidal Claims

There is an important regulatory distinction between preserving a product and making a biocidal claim about it. A preservative added to stop a water-containing formulation spoiling in the container is doing an in-can preservation job. A product sold on the basis that it kills or controls organisms is a different proposition, and biocidal products are subject to their own authorisation regime covering both the active substance and the product.

The distinction is not always obvious from the formulation, because the same substance can serve either purpose. What determines the regulatory position is the function claimed and the way the product is presented. If marketing language moves toward antimicrobial claims, the regulatory position can change without any reformulation at all - which is worth flagging to whoever writes the copy.

Making Preservation Work

Any formulation containing water is a candidate for microbial growth, and preservation failure is one of the more common causes of product complaints - visible growth, odour, discolouration or separation appearing partway through shelf life.

Preservative efficacy depends on the whole formulation rather than the preservative alone: pH affects activity, some ingredients bind or inactivate preservatives, and packaging affects contamination risk in use. Because of this, preservation is normally confirmed by challenge testing on the actual formulation in its actual packaging rather than assumed from the dose used. Regulatory approval status for preservatives also changes over time, so it is worth periodically confirming that the system in a long-established product remains permitted in your markets.

Preservation and Manufacturing Hygiene

Preservative systems are designed to maintain a product, not to rescue one contaminated during manufacture. Water quality, vessel cleaning and the microbiological state of incoming raw materials all affect the starting position, and a heavily contaminated batch can overwhelm an otherwise adequate preservative. Ask what microbiological controls the manufacturer applies rather than relying on the preservative alone.

Questions to Ask a Manufacturer

  • What preservative systems do you have experience formulating with, and are they UK BPR-approved?
  • How do you verify a product's shelf-life stability against microbial growth?
  • Do you have experience with cosmetics-specific preservative approval requirements, if relevant to our product?
  • How do you stay current with changes to approved/non-approved biocidal substances?

Frequently Asked Questions

Does every water-based product need a preservative?

Most do, since water-based systems are generally more susceptible to microbial growth than anhydrous ones, but the specific need and appropriate preservative depend on the formulation - discuss this with your manufacturer's formulation team.

Can a preservative approved in the EU be used in a UK product?

Not automatically - since Brexit, Great Britain operates its own standalone biocides authorisation regime, so approval status should be confirmed specifically for the UK market rather than assumed from EU approval alone.

Find a Manufacturer

Find a UK Contract Chemical Manufacturer

Search the directory of UK contract and toll manufacturers by process, industry and capability.

Search the Directory

Last reviewed: August 2026. Regulation and guidance change — verify anything you rely on against the primary source. Tell us if something here is out of date.