Tesco’s Metal Contamination Scare: How ISO 9001 Could Have Prevented a Food Safety Fail

In June 2025, Tesco issued an urgent recall of its Tesco Greek Style Natural Yogurt (500g), with a use-by date of 12 July 2025, following customer reports of metal fragments found in several tubs. The recall was officially posted on the Food Standards Agency (FSA) website and immediately caught national media attention due to the potential health risks posed by the contaminated product - especially for children and elderly customers.

But what exactly went wrong? And what lessons can other food retailers and manufacturers take away from this?

The Incident: What Actually Happened?

According to reports from both Tesco and industry insiders, the issue stemmed from a mechanical fault during production at a third-party processing facility contracted by Tesco. A metal component in the yogurt filling line had degraded over time - likely through wear and vibration - and began shedding small fragments during high-speed packaging operations. These shards went undetected during packaging and ended up in customer products.

Here’s a clearer breakdown of the failure points:

1. Equipment Maintenance Breakdown: The manufacturing plant's machinery had not undergone the appropriate preventive maintenance schedule, leading to undetected wear on a metal washer or blade in the filling mechanism.

2. Failure of In-Line Detection Systems: Metal detectors were installed on the line but were either not calibrated correctly, temporarily malfunctioning, or not sensitive enough to pick up small fragments embedded in thick yogurt. The audit trail on equipment calibration was reportedly incomplete.

3. Inadequate Final Product Checks: Final visual inspection was minimal and mostly randomised. Because yogurt is packed in opaque plastic tubs, visual inspection is almost useless without robust upstream controls.

4. Supplier Oversight Lapse: Tesco relied on third-party quality control documentation rather than conducting its own spot checks or unannounced supplier audits. This meant no one from Tesco was on-site to verify that controls were in place and functioning.

5. Delayed Traceability and Response: Once customer complaints started to come in, Tesco was initially slow to identify the batch due to inconsistent traceability data from the supplier. This delayed the recall and increased the risk window.

While no injuries were reported, the risk to public safety was real - and the reputational damage to Tesco was immediate.

How ISO 9001:2015 Would Have Made a Difference

ISO 9001 isn’t just a badge on a certificate. It’s a full framework for consistently managing product quality, risk, and traceability, particularly in complex supply chains. Here’s how its clauses directly apply to Tesco’s situation:

Clause 8.5 – Production and Service Provision

This clause requires organisations to control production equipment through scheduled maintenance, monitoring, and control plans. A properly implemented QMS would have flagged the wearing part for replacement before it failed.

Clause 8.6 – Release of Products and Services

Final product release procedures must include verification that the product meets all specifications. Had Tesco demanded metal detection validation records as part of their release criteria, the batch could have been quarantined.

Clause 8.4 – Control of Externally Provided Processes

Tesco’s third-party manufacturing facility was the weakest link. ISO 9001 requires regular audits and performance evaluations of external providers - not just documentation reviews, but on-site verifications. This would have spotted equipment or process weaknesses much earlier.

Clause 8.7 – Control of Nonconforming Outputs

Once the issue was discovered, the traceability breakdown delayed Tesco’s recall response. ISO 9001 mandates a clear nonconformity procedure: isolate affected product, record it, and act fast. A better internal recall process could have shortened Tesco’s reaction time.

Clause 10.2 – Nonconformity and Corrective Action

Beyond just reacting, ISO 9001 promotes root cause analysis and systemic improvement. Rather than blaming the supplier, Tesco would be required to assess how their own controls failed and implement preventive measures - like dual-level detection or more frequent inspections.

Key Lessons for UK Retailers and Manufacturers

This recall didn’t happen because Tesco doesn’t care about quality. It happened because the systems designed to prevent these failures weren’t robust or joined-up enough.

Whether you're a supermarket, a packaging supplier, or a food processor - if you’re not implementing and auditing a comprehensive Quality Management System, you're leaving your brand open to risk.

How ISO 9001 Protects Your Business

ISO 9001 certification helps your organisation:

• Ensure machine maintenance and process control are fully documented

• Manage supplier risk with regular reviews and audits

• Improve traceability, enabling faster and more targeted recalls

• Build customer confidence through consistent quality assurance

• Identify and eliminate root causes - not just symptoms

At AAA Certification Ltd, we help businesses across food production, retail, and logistics achieve ISO 9001:2015 certification with tailored support, practical guidance, and no jargon.

Don't wait any longer. Sign up to a Certification Audit with AAA and take the first step towards achieving ISO 9001 certification.