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physical contaminants

Identification of physical contaminants (“foreign bodies”)

Rapid and accurate identification of foreign body material found in food is essential in identifying the source of contamination and implementing measures to handle the incident and prevent recurrences. Pinpointing the stage in the food chain at which contamination took place can require skilled detective work. Information may be required on: country of origin; whether contamination occurred before or after processing, in the factory or during storage and distribution, or at retail point of sale; whether contamination was due to the consumer and if so, was it deliberate or accidental? An assessment may also be needed on the likelihood of the problem being restricted to one product or batch, or whether it is more widespread.

Ultimately a company or enforcement authority has to decide whether they are handling a safety issue with product recall implications, or a quality issue related to consumer perception or fair trading.

A useful working definition of a foreign body is “an object which can be seen by the unaided eye or felt in the mouth, and which the consumer perceives as being alien to the food”. This will therefore include not only items that are obviously foreign, such as insects, stone or glass, but also materials that are connected with the food, such as bits of stalk or apple core and burnt product. Foreign bodies may get into the food product at any point between growth of the raw materials and the consumer’s mouth.

Although this factsheet concentrates on the problems caused by yeasts and moulds, they are of course vital to the production of alcoholic drinks and bread. We have specialist sections within Campden BRI with a century of expertise – see our website at for details of services offered within the brewing and cereals sectors. We also have expertise in how fungi are used in agricultural situations – e.g. as biological control agents.

Systems should be in place to remove any foreign bodies from the product at various points in the manufacturing chain (see Campden BRI Guideline No.5 Foreign Bodies in Foods: Guidelines for the Prevention Control and Detection) or to highlight their presence and trigger appropriate intervention. However, the consumer's own home is another common source of foreign bodies. In any foreign body investigation it is important to accept that something has gone wrong and to suspend disbelief, implying that the foreign body could have come from almost anywhere. At the same time, it is also important to remember that experience shows that there are many well known, recurring sources of foreign bodies.

This sheet focuses on identification of foreign bodies once they are found. The examples given in this fact sheet are based on information given in Campden BRI's Guidelines for the Identification of Foreign Bodies Reported from Food (Guideline No. 4).


In the case of a foreign body found in the product by a consumer, it is essential that the details of each consumer complaint are properly recorded and kept on file. Regular reviews of these data will provide information on any patterns emerging from complaints. Initial information recorded may depend on the retailer or enforcement officer, over whose systems the foreign body identification laboratory may have little or no control, but the fullest information obtained at this time will save much time and wasted effort later. Where the foreign body could have originated from the packaging (e.g. glass, metal, plastic), try to obtain the packaging from the product both for comparison and to determine whether or not any portion is missing, or whether tears, holes or other damage may be present.