Physical contaminants (or ‘foreign bodies’) are objects such as hair, plant stalks or pieces of plastic/metal that can occur as contaminants in food. Sometimes the object is a natural component of the food (e.g. a fruit stalk) - but in all cases it is important to find out what it is and how and when it got there. Campden BRI offers a fast, accurate service for the identification of adventitious and deliberate contaminants, helping to pinpoint its source and advising on preventative solutions.
Light microscope examination for features such as size, colour, curvature and deposits is followed by X-ray microanalysis in the scanning electron microscope. This quick non-destructive test gives a spectrum of the elements found in a sample, allowing for rapid identification.
Metal, stone and plastics
These, and other non-biological materials, are subjected to a similar examination process to that used for glass samples. X-ray microanalysis can distinguish between different metals, including the different types of stainless steel. With plastics, other techniques such as Fourier Transform Infrared (FT-IR) spectroscopy can be used to "fingerprint" the material. This technique is also invaluable for many pharmaceutical tablets and capsules.
Extraneous vegetable matter
This is often identified by light microscopy to demonstrate its cellular structure, using various histochemical stains to identify the chemical nature of the material. Similar approaches can be used to identify other similar samples such as rodent droppings.
Hair and fibres
These are usually identified using light microscopy and compared with a reference collection of known samples.
Has it been heat processed?
Heat processing of many once-living samples destroys enzyme activity in the sample, and hence tests for enzyme activity can be used to determine if the sample has been heat-treated in many cases. In other cases, such as glass or metal, the condition of surface deposits such as starch can give indications as to the history of the sample.
Other foreign bodies
The above is only a selection of the foreign bodies which are most frequently identified. We have a wealth of experience of dealing with a wide range of unusual objects over many years.
We also run a foreign body proficiency identification scheme (FOBS) for other laboratories to check their competence.
Where we refer to UKAS Accreditation
The Campden BRI group companies listed below are both accredited in accordance with the recognised International Standard ISO/IEC 17025:2005 by the United Kingdom Accreditation Service (UKAS). The accreditation demonstrates technical competence for a defined scope of methods, specific to each site, as detailed in the schedules of accreditation bearing the testing laboratory number. The schedules may be revised from time to time and reissued by UKAS. The most recent issue of the schedules are available from the UKAS website www.ukas.com
Campden BRI (Chipping Campden) Limited is a UKAS accredited testing laboratory No. 1079 Campden BRI (Nutfield) is a UKAS accredited testing laboratory No. 1207