Testing Labs Play Detective When Food Processing Goes Wrong

The science and process of keeping food safe for the consumer is highly regulated, as we all know. The industry’s biggest concern often revolves around contaminants that enter into the food handling system and somehow go out to market.

Yet, from time to time, unidentified matter such as metallic particles, hardened organic objects, paint or coatings, and industrial lubricants that originate from the process itself show up in our foods and liquids. Not only is this alarming for the consumer, incidents such as these can make the news and ruin the reputation of the food company.

To keep food safe, both government food regulators and companies that outsource food processing constantly demand the implementation of multiple redundant systems to prevent these events before the damage is done. Food producers are well aware that in offering consumable, edible products for the public, they must follow rigorous guidelines to ensure that fragments from contact items such as knives, augers, receiving bowls/containers, and other processing devices do not end up in the final product and reach consumers.

Unfortunately, the origin of these potentially harmful foreign particles is not always readily apparent. Quite often, a food operation must call upon an off-site materials laboratory to do the detective work necessary for identifying this material and, most importantly, determining how it got there.

This scanning electron microscopy image shows a high magnification of metallic debris found in a processed beef jerky sample.

Sleuthing for the Culprit

Food processing involves a tremendous number of mechanical devices to keep pace with demands and production schedules. There are knives, rollers, conveyors, gears, and a plethora of other devices required in production. And one thing all mechanical devices have in common is that they eventually wear out.

The designers and manufacturers of these devices intend for the processed food to stay clean and sanitary. Unfortunately, processing equipment can send unwanted particles and chips into the processed food stream, usually in the form of nylon, plastic, and other polymer items. At other times, the components can be metallic. Periodic maintenance and inspection of processing equipment are the front line defense against machine wear.

In-stream monitoring devices positioned throughout the processing sequence provide progressive testing to uncover any non-product matter. These precautions may include magnetic separation and collection units that are in the processing stream to quarantine these errant and stray metal flakes, chips, powder, and other forms of metallic debris. Most equipment that processes large volumes of product is designed to rigorous standards to ensure the highest quality product and eliminate consumer danger. A metallic shard can break teeth, cause broken bones in the jaw region, and result in intestinal damage.

If the fragment is not caught at the processing plant but goes off to market, simply recovering it is not enough. The manufacturer must determine the area of the machinery from which it came. A materials laboratory has the proper equipment and tools to analyze inorganic and organic contaminants found in food, deal with production contamination issues, and uncover the source of the foreign object.

This shard of metal was analyzed at a materials testing lab and determined to be a high-carbon steel typical of a cutting blade. Analysis was achieved using energy dispersive spectroscopy, which is well-suited for small samples such as this 3mm specimen. Further investigation determined the cutting blade was excessively brittle caused by inappropriate heat treatment.

Sometimes pieces are so small that a special analytical approach is required. These pieces are typically analyzed using a scanning electron microscope that uses energy-dispersive X-ray spectroscopy to perform a chemical analysis. Determining the material family may allow the equipment manufacturer to laser in on the component that has been damaged or is failing.