Q&A: Physical & chemical contamination in food manufacturing

We asked Technical Specialist Clare Ray and Senior Scientist Dr Alan Wood about their experiences in dealing with physical and chemical contamination across their extensive careers. Here's what they said.

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What is a contaminant?


In basic terms, a contaminant is something present in food or drink that shouldn’t be there and generally falls into one of four categories; chemical, physical, microbial and allergenic. It can be present due to agricultural practices, environmental factors, manufacturing, processing, packaging, transport and consumers.




What are some of the most common sources of physical and chemical contamination in food manufacturing and retail?


Physical and chemical contamination can be intrinsic to the product itself, such as gristle and bone, or formed by chemical reactions that take place during processing. But it can also enter the food chain from multiple sources. 


Factories present many potential risks. Plastic parts and stainless steel metal particles from production lines, as well as cleaning fluids, oils and lubricants are all common suspects. Insects and rodents have also been known to find their way into products via harvested raw materials.


Packaging and storage can also cause contamination issues. External fibres and particles can be the source, as can packaging that breaks down in transit. A plastic tray, for instance, can shatter into multiple tiny shards. Adhesives, containers and wooden pallets are also often found to be the cause of chemical contamination migrating into food and drink products.


Perhaps not surprisingly, consumers can sometimes be the root cause of contamination. Generally, it happens accidentally such as the backwash of medicinal tablets into drinks. However, there are instances where contaminants have been added intentionally to products, either to damage brand reputation or extort money from the manufacturer or retailer.




What are some of the challenges companies face around chemical and physical contamination?


Although metal detectors installed on production lines will alert manufacturers to some important contaminants, such as ferrous metal, other common foreign bodies can’t be found in this way because the technology is simply not available - plastic is very much a case in point.


Tracing the problem back to the root cause can also be a challenge. A medicinal off taste in a drink, for instance, may be the result of a small leak in the original processing line, which allowed lubricants to enter the product and cause the reactions that then created the unwanted flavour profile.


It’s equally important to be aware that the investigation will be complicated if the contamination originates at the end of the supply chain. Manufacturers don’t have control of products once they leave their site, but the retailer’s storage conditions may be the source of the contamination – making for a time consuming and complex problem solving exercise.




How can RSSL support the food and drink industry with contamination investigations?


Speed of response is vital. Contamination not only threatens consumer safety and brand reputation, it also raises the very real possibility of an expensive product recall. But companies can only take effective action if they know what it is and where it came from. At RSSL we understand the urgency, which is why we offer an emergency response service. It gives customers access to our technical experts 24/7 and provides rapid analytical results, enabling them to make informed, business critical decisions to resolve the situation.


Of course, every contamination project is different and we tailor our approach accordingly. Our state-of-the-art laboratories feature a wide range of analytical technology, from sophisticated microscopes and mass spectrometers to spectrophotometers. We can also use an assortment of quick and simple tests to identify a range of common chemical contaminants such as detergents, bleaching agents and drugs of abuse. Whatever the issue, our analysts apply their extensive expertise to identify and quantify the contamination, while our toxicologists determine if it poses a risk to consumer safety or health. We can also provide equally accurate and reliable root cause analysis, along with legal documentation for court proceedings, if required.




What steps can companies take to mitigate the risks of contaminants entering the food supply chain?


We recommend an integrated approach to risk management. Implementing a Hazard Analysis and Critical Control Points (HACCP) programme in conjunction with a Threat Assessment Critical Control Points (TACCP) plan is a good place to start. HACCP involves identifying potential hazards at each stage of the food production process and implementing controls to prevent or eliminate those hazards. While TACCP can be used to assess the risks of issues such as malicious contamination and tampering.


At the same time, putting several important measures in place will not only help to build a stronger defence, but also ensure the business is prepared to respond swiftly and effectively in the event of a contamination incident:


  • Supplier control programmes: Work with suppliers to ensure the raw materials and ingredients they provide meet quality and safety standards. Ask questions about what hazards may be present unintentionally, then request information about how they are managing those risks and evidence to demonstrate they have been prevented, eliminated or reduced to an acceptable level. This generally requires the supplier to implement testing and verification procedures to ensure compliance or the manufacture to establish some form of surveillance testing to monitor the higher risk-rated materials.


  • Intentional contamination: Consider potential threats to supplied ingredients from deliberate contamination or adulteration and, where relevant, implement confirmatory testing plans.


  • Production risk assessment: Carry out a thorough risk assessment of the production process to identify potential hazards. Then establish robust controls that will prevent, eliminate or reduce those risks to an acceptable level. These controls need to be validated to provide evidence of their efficacy. This could involve testing for contaminants at various stages of the production process, as well as testing finished products to ensure they meet defined safety and quality standards.


  • Employee training: Provide employees with regular training on all aspects of food safety principles and procedures within the manufacturing environment, as well as ongoing education on emerging risks and best practices. A business with a well-established food safety culture is more likely to implement good food safety practices and procedures successfully.


  • Product recall plan: Develop a plan for responding to a potential contamination incident, including identifying the source, notifying relevant stakeholders and initiating a product recall if necessary. This will involve partnering with a laboratory with the relevant expertise and emergency response capability. It may also include specialist support to establish whether an incident is a significant food safety or health risk for consumers.


Of course, every plan should be reviewed regularly and, whenever significant changes have taken place, be subjected to an in-depth review. At the very least, this should involve an annual review of the risk assessment/risk management process to flag any significant developments. The whole planning and execution process must also be well documented. 

Meet RSSL's contamination experts

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    Clare Ray

    Technical Specialist in our Microscopy laboratory.


    Over the last 25 years, she has worked on thousands of foreign body investigations ranging from ordinary pieces of glass and plastic to rodents and sediments causing blockages in filters and pipes. 

  • Alan Wood

    Dr Alan Wood

    Senior Scientist in our Investigative Analysis Laboratory.


    As a technical expert in chromatography and mass spectrometry, Alan uses his extensive knowledge and experience to solve a wide range of chemical contamination issues, ranging from routine taints and flavours to more complex intentionally-added substance investigations.


Need help with physical and chemical contamination investigations?

We have extensive experience and expertise in contamination problem solving and with the latest analytical technologies and our Emergency Response Service we can provide crucial support when you need it most. Our multidisciplinary team of technical experts can identify and quantify physical, chemical and allergen contaminants, our toxicologists can perform risk assessments to determine if there is a risk to public health.  We can also support with root cause analysis investigations and implementation of allergen food safety training.  If you would like any further information or to make an enquiry, please contact us via the form below.


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