How to Audit Your PET Preform Supplier: A Procurement Checklist

A practical procurement checklist for auditing PET preform suppliers — certifications, documentation, traceability, and red flags.

Why audits matter

A bad preform supplier creates problems that surface 6 months later: shelf-life failures, customer complaints, recalls. Annual audits catch issues before they reach your filler.

Pre-audit document review

Request: FSSC 22000 certificate, ISO 9001:2015 certificate, recent third-party audit report, list of resin suppliers, sample COA / COC, migration test reports per EU 10/2011 and FDA 21 CFR 177.1630.

On-site audit checklist

Verify: Husky or comparable injection systems with documented efficiency, IMD or equivalent vision inspection on every cavity, lot-coding back to resin batch, segregated storage for food and non-food materials, calibrated metrology equipment.

Red flags

Watch for: outsourced labour (broken accountability), undocumented shift changes, missing or expired calibration stickers, mould maintenance done off-site by unknown vendors, "we mix in regrind sometimes" (food-contact violation).

Quality system depth

Ask to see: deviation reports from the last 12 months, customer complaint log, corrective-action records, supplier qualification dossier for resin. A supplier that shows you these proactively is a supplier you can trust.

Traceability test

Pick a random preform from finished-goods stock. Ask the supplier to trace it back to: mould cavity, shift, operator, resin lot, resin supplier, and any deviations. A real traceability system gets you that in 15 minutes.