Total picture on fragment and foreign body analysis

Total picture on fragment and foreign body analysis

GTS Development Technologist and former Forensic Science Service Analyst, Andrew Broadhurst, explains how the analytical capabilities available for fragment and foreign body analysis can save manufacturers and processors both time and money.

Manufacturers and processors know the potentially devastating impact of customers finding foreign objects in their products, particularly when those products are foods, drinks or pharmaceuticals.

The glass container supply chain is too often the first to be blamed when a foreign object is found in a product and it is vital to identify whether the fragment has been introduced during glass manufacture, filling, processing – or by the customer after purchase.

Identification of the likely source can be determined by analysing the evidence present on the particles found and, if a source is suspected, through comparative analysis. In the majority of cases, the glass can be shown to differ from the container in question. It’s also not uncommon for complaints of glass in products to arise from non-glass materials such as plastics, salt crystals or naturally occurring minerals.

Accuracy and speed are clearly vital in terms of analysing the foreign material, which is  why we’ve been investing heavily in our fragment analysis service, both for glass and non-glass samples, enabling us to identify the most likely source of stray glass, plastic, polymer or other material and – most importantly – exclude potential sources.

In the majority of cases submitted to us, contamination by the manufacturer or processor is not the most logical explanation, even when glass and plastic packaging is used.

In one test programme for the food and drink sector, we found that 70% of fragments, which had been found in products by consumers and submitted for analysis, had originated from items commonly found in the home, such as measuring jugs, mixing bowls and jars and of the remaining 30%, nearly all could not have been introduced in the food manufacturing process. The random selection of 125 samples showed:

  • 32% were borosilicate based glass: typical for cookware and glassware made to withstand high temperatures and most likely to have been inadvertently introduced by the customer during cooking, from measuring jugs or casserole dishes;
  • 38% were clear soda-lime-silica based glass: a common glass composition used for a wide range of products, including jars, bottles or mixing bowls, commonly found in the home;
  • 30% were from other sources including lead crystal items, green soda-lime-silica container glass and flat glass, but the majority from non-glass sources, including naturally occurring salt. In one case, we even found a piece of tooth that belonged to the complainant.

We’re able to issue results electronically within 24 hours of receiving the sample or, depending on the urgency, within a few hours. In many cases we’ve been able to help manufacturers avoid product recalls as well as of course protect their vital brand reputation.

Of course composition alone is not enough to determine the source of an object, as a wide variety of items could be made from the same kind of glass. We also look at the original shape of the article and its particular profile, which may not match the packaging.

Then we look at how it failed, in other words how the fragment was formed and what happened to it after the chip, crack or breakage. If potential sources of the fragment are available, we can match or exclude in order to narrow down the options.

We’re using a range of analytical techniques to determine fragment identity – using technology widely used in forensics, including:

  • SEM-EDS (Scanning Electron Microscopy - Energy-Dispersive X-ray Spectroscopy) – which measures the chemical composition of each sample, while allowing surface features to be examined at very high magnification;
  • GRIM3 (Glass Refractive Index Measurement) – which combined with potential sources, provides strong evidence for product matching. We can very precisely determine whether the RI of the fragment matches that of the container – even if they look exactly the same or use exactly the same ratio of raw materials, they will have unique chemical element markers – akin to finger-prints or DNA – and this alone, in many cases can give a definitive answer;
  • FTIR (Fourier Transform Infra-Red) Spectroscopy – which gives us valuable information about molecular structure, particularly useful for identifying plastics and polymers, such as polystyrene and polypropylene, for example;
  • BIO-RAD’s KnowItAll spectral database  - enabling us to provide extensive sample identifications across plastics, polymers and other materials.

Combining these techniques and our unique understanding of glass composition, forming and failure, we’re able to assess a range of vital clues and provide clients with a comprehensive report on a sample’s properties and likely source and can work with suppliers, manufacturers or brand owners to audit processes or investigate potential sources on-site.

Given the potentially huge financial and reputational costs related to recalling or withdrawing product and the potential for costly litigation, it’s obviously vital that any decisions are based on reliable and accurate information.

We also support the industry in the development of new container designs, using our extensive experience of mechanical and physical testing. We’ve recently introduced Finite Element Analysis (FEA) to provide computer-simulated performance data in areas such as resistance to internal pressure, impact and vertical load resistance.

Brand owners and glass manufacturers are increasingly using the service at the pre-prototype stage, in order to resolve any design issues before major costs are incurred. That same pre-production analysis is not only popular in the container glass sector, it is also used extensively in flat glass, particularly by the construction, architectural, automotive and marine industries.

But it’s not just a matter of prevention being better than cure. It’s also about enabling true innovation in the creation of the aspirational and unique designs that brands rightly demand in order to make their product get noticed by the target consumer, or to serve novel or special applications. It’s a continuous challenge the glass supply chain is more than ready to meet.

Full details of the test programme and further details about our foreign body and other analysis services are available on our newly launched website at

Reproduction of this published material is provided courtesy of Glass International. Published in Glass International October 2013.

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