Third-Party Manufacturer Quality System: What to Check Before You Sign

A third-party manufacturer's quality system is what turns a good sample into a good bulk batch, every time. It should show up as documents you can inspect: batch records, raw material specifications with certificates of analysis, in-process checks, release testing, retained samples, traceable batch codes, a complaint process, change control, and records for calibration, cleaning and supplier approval. A certificate on the wall proves a system exists. The records prove it works.

Most brands only look at the sample and the quote. The problem is that samples are made by hand under close attention, while your reorder in month eight is made on a busy day by a different shift. This guide covers what to look for, how to ask for evidence politely but firmly, and what ISO, GMP and Halal certificates do and do not tell you. It sits within the broader third-party cosmetic manufacturing guide.

Start with the batch record

Ask to see a blank batch manufacturing record, and then a completed one with the client name hidden. A good one lets someone who was not there reconstruct what happened.

• Product name, batch number, batch size and date.
• Every raw material used, with its lot number and the quantity weighed.
• Step-by-step process instructions with space for times, temperatures and mixing speeds.
• Signatures or initials for who weighed, who checked and who approved.
• Yield at the end and an explanation for any difference from the expected figure.
• Deviations noted and signed off, not quietly corrected.

If records are a spreadsheet filled in at the end of the week, treat that as a gap. Records are only useful when made at the time the work is done.

Raw materials: specifications, COAs and approval

Product quality starts at the gate. Ask how incoming materials are handled.

• Specifications. Each raw material should have a written specification: what it is, the grade, and the limits it must meet.
• Certificates of analysis. The supplier's COA should accompany each lot and be matched to the lot received. Ask whether the plant also tests anything itself, or relies entirely on the supplier's paper.
• Quarantine. New deliveries should be held, labelled and released before use. Look for a physical area and a status label system, such as quarantined, approved or rejected.
• Approved suppliers. There should be a list of vendors the plant buys from, with a reason for approval and a review process. Ask what happens when a supplier changes a grade or when a material is out of stock. Substitution without approval is where quality quietly slips.

Checks during production

In-process control catches problems while they are still cheap to fix. Ask which checks apply to your product type and where they are recorded. Typical ones include pH, viscosity, appearance, colour and fragrance against a reference, and fill weight or volume during filling. For an emulsion, ask who confirms the batch is uniform before it goes to filling.

Also ask what happens when a check fails. Good answers describe a hold, an investigation, a decision by a named person, and a written record. Weak answers sound like "we just adjust it".

Release testing before anything ships

Finished product should be checked against its specification and formally released by someone other than the person who made it. Ask for the typical release test list for your product category, and for a sample release certificate or COA.

Microbiological testing deserves a direct question, especially for water-containing products. Ask what is tested, how often, and whether it is done in-house or by an outside laboratory. Stability and safety work belongs earlier in development and is covered in stability and safety testing before launch. Release testing is the routine check that each production batch matches the approved one.

Retained samples, batch codes and traceability

These three work together, and you can test them in a few minutes.

• Retained samples. The plant should keep a sample from each batch for a defined period, stored properly. If a customer complains six months later, this is what you compare against.
• Batch codes. Each unit should carry a code that links to its batch record. Ask where the code is applied and who checks that it is legible.
• Traceability. Pick one finished batch and ask the plant to trace it back to the raw material lots, and forward to the customers who received it. A competent quality team can do this from records in a reasonable time. If the answer is "we would have to search", note it.

Complaints, deviations and change control

Every plant has problems. What separates good systems is what happens afterwards.

Ask to see the complaint procedure and one redacted example showing receipt, investigation, root cause and corrective action. Ask how you, as a brand, will report a problem and who will respond.

Change control matters just as much. Raw material supplier changes, equipment changes, process tweaks and packaging component changes can all alter your product. Your agreement should say that no change affecting your formula, specification or materials is made without your written approval. The legal side of this is in key terms in a contract manufacturing agreement.

Calibration, cleaning and the factory floor

A scale that is out by a few grams ruins a small-dose active. Ask whether balances, pH meters, thermometers and filling machines are calibrated on a schedule, and see the labels and logs. For cleaning, ask how equipment is cleaned between products, who verifies it, and how fragrance or colour carry-over is prevented. If the plant makes scented candles, hair colour or strong fragrances on the same line as your light product, ask how that is controlled.

A walk-through, in person or on video, tells you a lot: tidy storage, labelled containers, separated raw and finished goods, staff in clean clothing, and records near the point of work rather than in an office.

How to ask for evidence

Asking for records can feel awkward, but a serious manufacturer expects it. A clean approach:

1. Send a short written request listing the documents you want to see, such as a blank batch record, a sample COA, the complaint procedure, a recall or traceability example and the list of in-process checks.
2. Ask for redacted samples, so no other client's information is exposed.
3. Request a live demonstration: trace one batch, or show one calibration log.
4. Offer an audit, in person or remote, once you are serious. A plant that refuses any visit or video walk-through is giving you information.
5. Write down what you were shown, so you can compare it with what you receive later.

The testing and quality page at Harrods Health sets out testing and quality information, and the guide to choosing a third-party manufacturer shows where quality fits next to price, timelines and communication.

What ISO, GMP and Halal certificates do and do not prove

Certificates are a useful first filter. They are not a substitute for looking at records.

• ISO certification usually means an independent body has audited a management system against a published standard. It shows that processes are documented and reviewed. It does not tell you how good your particular product is, and which standard applies matters. Ask which one, the scope, the issuing body and the expiry date.
• GMP compliance describes good manufacturing practice: how a plant should control materials, people, premises and records. Some GMP statements are self-declared and some are audited by a third party. Ask which.
• Halal certification confirms that ingredients and processes meet halal requirements, which matters for certain markets. It is not a general safety or efficacy mark, and it covers the scope listed on the certificate, which may be specific products or lines.

For any certificate, read the scope, check the site address matches the plant that will make your product, confirm it is current, and ask who audited it. Harrods Health describes its facility as ISO certified, GMP-compliant and Halal certified, with HACCP and Kosher certification also held. Scope details are on the quality certifications page. The same questions apply to every manufacturer you talk to.

A short scorecard

After your review, rate each area as shown, partly shown or not shown: batch records, material specs and COAs, in-process checks, release testing, retained samples, traceability, complaints, change control, calibration, cleaning, and supplier approval. Several "not shown" answers, especially on traceability and change control, are worth treating as red flags when vetting a contract manufacturer.