Foreign body ID: What, when, how
21 December 2009
Few things worry food companies as much as a foreign body complaint. Repercussions can involve product recalls, brand damage or legal consequences if produce is deemed to have breached the Food Safety Act.
As with crisis situations, however, a swift but measured response is by far the most effective. Foreign bodies can be a contentious topic - the retailer will want explanations from the manufacturer who in turn might look to its suppliers.
Yet it's sometimes the case the foreign body entered the food in the complainant's home - whether by accident or design. By acting quickly to establish the root cause of the problem, a considered, strategic response can be developed to resolve the matter with minimal fallout.
Any exploration into foreign body contamination should aim to establish three core facts: what it is, how it got there and when it got there. Clearly, the more specific we can be the better. But it's important to understand the complexity of the issue.
The term 'foreign body' is used to refer to anything that can be seen by the unaided eye or felt in the mouth, that the consumer perceives as being alien to the food. So that could include natural materials such as stalks or pips. A foreign body can in fact enter the food chain at any point between growth of the raw material and the moment of consumption, and the range is virtually without limit.
The first question to be answered in a foreign body investigation is 'what is it?' Sometimes the answer may seem obvious but it always deserves a closer look - things aren't always as they first appear. Stories of large beetles and other undesirables baked into bread have proved, upon more thorough examination, to be little more than unfortunately shaped pieces of hardened dough. And it isn't unheard of for rock salt added to food by the consumer to be mistaken for fragments of glass.
Explicit identification of the foreign body can play a vital role in determining the point at which it entered the food chain, who holds responsibility and how recurrences can be prevented. A piece of glass or metal always warrants thorough examination. It is relatively quick and easy to identify whether it's industrial grade material or something more likely to have originated in the consumer's kitchen, such as chips of Pyrex. Straightforward laboratory tests or microscopic inspection can provide many answers within 24 hours in cases of emergency.
There can, however, be a tendency to push for more detail than is technically possible or financially worthwhile. For instance, when hair is found in food it would take much effort and expense to trace the individual it belongs to through DNA testing, even if the necessary reference samples could be obtained for comparison from all likely sources. It's technically possible to do this but would rarely be cost-effective to do so.
While it's natural to want to know the precise nature of a foreign body, the most important concern should be how and when it got into the food. Sometimes identifying the composition will provide enough evidence to indicate whether contamination happened during the production phase. Size can also be an important indicator: if the production process incorporates filling nozzles which are smaller than the foreign body, it can immediately rule out the factory as the source.
If initial size and composition based investigations are inconclusive, a further consideration is the likely impact the production process would have on the object in question. At Campden BRI we've conducted extensive tests to ascertain the effects of processes such as baking and canning on objects commonly reported as foreign bodies, including woods, plastics, metals and insects, publishing reference guides on this topic.
Evidence that the object has been processed may include changes to the foreign body (such as melting, discolouration, distortion), food deposits stuck to its surface, changes to the food itself or alkaline-phosphatase activity to determine whether an object that was once living has been heat processed. Likewise, these tests can sometimes be used to prove the material has never been processed at all.
Rapid response and due diligence should be the watchwords for food industry professionals when a foreign body is reported. It is important to act but not to overreact. Quickly establishing the likely source and the scale of the incident enables appropriate and proportionate remedial action to be taken.
* Mike Edwards is head of microscopy at Campden BRI
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