Food safety incidents involving foreign materials can quickly escalate into potential recall situations. However, not every incident results in a widespread risk.
This example outlines a real situation involving metal contamination in a food product and demonstrates how detailed investigation and evidence-based reasoning can determine whether a recall is necessary.
What Happened
A customer reported finding a piece of metal in a food product and raised a complaint with New Zealand Food Safety.
This was unexpected, as the product had passed through a metal detection system during processing. The business was unable to immediately explain how the contamination could have occurred.
At this point, the situation had the potential to escalate into a recall, but further investigation was required before making that decision.
The Investigation
The first step was to gather as much evidence as possible.
- The affected product batch was identified and traced back to a specific production day
- Photographs and physical evidence of the metal fragment were obtained
- Site activity records for that day were reviewed
It was identified that external contractors had been working onsite on that day, carrying out unrelated work in a different part of the facility.
Although this work was not directly connected to the production area, it introduced a potential pathway that needed to be explored.
Identifying the Source
Closer examination of the metal fragment suggested that it was consistent with material generated during drilling operations.
An independent review confirmed that the fragment appeared to be a piece of metal swarf, likely produced when drilling into metal.
Further investigation established:
- the fragment was part of a single piece that had broken into two
- it was not multiple fragments from ongoing contamination
- it was consistent with a one-off event
The contractor involved confirmed that the material was consistent with their work.
Understanding How It Entered the Product
The key question was how material from a separate area of the facility could have entered the product.
Through interviews and site assessment, a plausible pathway was identified:
- contractors were required to pass through a production-adjacent area to access shared facilities
- a small fragment could have adhered to clothing or equipment
- the fragment may have dislodged at a specific moment and entered an exposed product
While this sequence of events was highly unlikely, it was consistent with the available evidence.
Assessing the Risk
A critical part of the process was determining whether this was:
- an isolated incident, or
- a systemic issue affecting multiple products
Several factors were considered:
1. Nature of the contamination
The fragment was identified as part of a single piece, rather than multiple fragments.
This supported the conclusion that the contamination event occurred once, rather than repeatedly.
2. Probability of recurrence
The pathway required a very specific set of circumstances to occur.
The likelihood of the same event happening again was extremely low.
3. Metal detection performance
The product had passed through a metal detector.
It is recognised that detection systems are not perfect and can be influenced by the orientation and shape of metal objects.
While it was possible for a single piece to pass undetected, the probability of multiple identical failures was considered very low.
4. Absence of additional incidents
No further complaints or incidents were reported.
This supported the conclusion that the issue was not widespread.
Outcome
Based on the available evidence, it was concluded that:
- the contamination was a one-off incident
- there was no indication of ongoing risk to other products
- a full consumer-level recall was not justified
This position was presented to the regulator, along with the supporting evidence.
The assessment was accepted, and a recall was not required.
Why This Matters
This example highlights an important point:
Not all food safety incidents require a recall.
A recall should be based on:
- evidence of risk
- likelihood of affected product remaining in the market
- and whether the issue is isolated or systemic
In some cases, a detailed investigation can demonstrate that the risk is limited to a single product.
Practical Lessons for Food Businesses
This scenario highlights several key lessons:
- Traceability systems are critical for narrowing down incidents
- Site activity records (including contractor work) can be essential evidence
- Understanding contamination mechanisms helps build credible explanations
- Probability and risk assessment play a key role in decision-making
It also reinforces the importance of controlling contractor movement and access within food production environments.
Where Mock Recalls Fit In
Situations like this are exactly why mock recalls are required.
A mock recall helps test whether a business can:
- trace affected product accurately
- gather and assess evidence
- communicate clearly with regulators
- and make informed decisions under pressure
Without a structured approach, it is much harder to demonstrate that an incident is isolated.