Analysis of foreign objects in foodstuffs
ifp is expanding its analytical capacity. Having acquired a scanning electron microscope with Energy dispersive X-ray spectroscopy (SEM/EDX) and a Fourier Transform Infrared Spectrometer (FTIR) we are now able to offer industrial clients services in the identification of foreign objects. Do you have questions concerning the analysis of foreign objects or a case which requires investigation? Click on the telephone symbol and call us.
Material composition and sources of foreign objects in food
If a foreign object is identified in a product or raw material, the question which arises is the material and origin of the item. In case of consumer complaints due to foreign objects, a plausibility check is often of interest and can be examined as well. Various foreign objects have been found or been the cause of complaint in foodstuffs in the past, ranging from splinters of glass or plastic originating in the production process, to metallic wear debris to hair, stones, plant components, insects, as well as tooth and bone fragments.
Determination of the element composition of foreign objects by SEM-EDX
The first step in clarifying the issue is usually the analysis of material composition of the foreign object. Using an SEM-EDX allows us to determine the quantitative element composition of the object. Especially anorganic materials such as metal, glass, salts are easily identifiable and can ideally be traced to a certain source through the element specific fingerprints of comparison samples.
In the case of those foreign objects which are sent in for investigation, it is important to test and, if necessary, prepare the objects in advance in each individual case, as organic materials cannot be reliably identified using REM-EDX. The EDX method is based on the emission of a beam of electrons, which causes the release of element-specific X-rays from a surface layer of few micrometers. Elements with an atomic number of ≤ 4 (Beryllium) or ≥ 95 (Americium) cannot be determined. The result of the determination is a table presenting the constituent elements by percentage. Thus, for example, a ratio of iron to chromium ratio of 4 to 1 indicates the presence of stainless steel.
Analytical challenges with organic foreign objects in food
Due to the ubiquitous occurrence of carbon and oxygen, particularly pure organic materials cannot be quantified reliable in the SEM-EDX. However, a sole SEM analysis without the EDX can be useful as well to localize characteristic surface structures and allow a comparison and potential identification of the foreign body.
Often, the identification of organic foreign bodies (e.g. plastic particles) requires the use of FTIR instead. For this process, optical interference is recorded in the form of an interferogram, which is then mathematically converted into the IR spectrum by means of a Fourier transform, which is then compared with a database in order to determine material make-up of the substance or material.
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