The analysis of products represents a fundamental component of any assurance programme for the safety, quality or authenticity of a product. The global market for food safety testing alone was estimated by one market research company to be worth $17 billion in 2022 and predicted to grow to over $21 billion by 2030. Analytical test results are often used as part of critical decision making in product assurance, sometimes assuming undue significance, and it is incumbent on industry professionals to carefully consider the rationale for analysis, the choice of analytical method, the capability of the laboratory and the interpretation of the result.
This article will review the different use cases for analytical testing in the food and non-food industries and associated considerations to ensure value-added outputs from its use.
History and Background to Testing
The testing of food and non-food products is intrinsically linked with the development of techniques and technologies to identify chemicals and microorganisms in products and the physical attributes of them. Microbiological ‘testing’ was initially confined to visual means with the development of early ‘microscopes’ by the Dutch textile merchant Antonie Van Leeuwenhoek in the 1600’s. However, this was in the period where spontaneous generation remained a widely accepted phenomenon and it wasn’t until the late 1800’s that broth and agar techniques for the cultivation of microorganisms from foods and clinical specimens emerged through the work of Louis Pasteur and Robert Koch. Cultural techniques began to be widely employed for routine testing of food products and medical specimens throughout the 20th Century and remain some of the mainstay approaches for microbial detection to this day although immunological and genomic based analysis are now methods in wide use for microorganisms, often in combination with cultural methods. An excellent information source for such methods is the Bacteriological Analytical Manual produced by the US Food and Drug Administration.
Safety and quality were perhaps the key drivers of microbiological testing but, in the case of chemical testing, this was unquestionably driven by fraud and the need to ensure that foods were authentic and not contaminated with unspecified and often unsafe inclusions. The pioneers in this regard were Friedrich Accum who published his ‘Treatise on Adulterations of Food and Culinary Poisons’ in 1822 and Arthur Hassall who conducted widespread analysis of food for adulteration and who’s work led to the Adulteration of Food and Drugs Act in 1860, one of the first key laws relating to food. Rather ironically, much of the early work on food adulteration involved the use of microscopical techniques to identify foreign substances such as insects and other material. The USFDA also provides a very useful resource for information on chemical methods.
In relation to consumer products testing, general merchandise products such as kitchenware, white goods e.g. fridges, washing machines, toys, etc. were historically tested to ensure they were fit for purpose. Therefore, many of the early tests were based on mechanical fitness for use such as weight bearing, in use durability, etc. Standardised and often automated testing for these attributes were developed in the 20th century in response to consumer protection legislation such as the UK Consumer Protection Act 1961 and the US Consumer Product Safety Act 1972. Legislation served to drive the widespread introduction of industry standards now issued through international and national standardisation bodies such as the International Organization for Standardization (ISO), the European Committee on Standardization (CEN) and the British Standards Institution (BSI). Globally, there are 194 organisations from 144 countries / territories recognised as standardization bodies according to ISO. Testing for general merchandise products is now extensive and varied incorporating many tests for safety including flammability, electrical safety, choking, etc. In addition, general merchandise products are also tested for many chemical hazards as these have become recognised over the years as presenting safety risks to users including heavy metals e.g. lead, mercury, etc, and migrants such as phthalates, Bisphenol A, etc.
Formulated consumer products such as cosmetics and formulated household products such as skin care, detergents, disinfectants, deodorisers, etc. have followed a similar testing path to general merchandise with legislative standards driving the specific testing requirements with many such tests being highly specialised and specific to the product category. For example, toxicological assessment of skin care products, disinfection efficacy testing of disinfectants and performance testing of antiperspirants and deodorants, etc.
Rationale for analysis
If you don’t know why you are conducting a test then it is probably not doing the test. I would strongly advise all industry professionals to scrutinise their analytical assurance programmes with this in mind and I am sure you will deliver an instant improvement in the cost effectiveness of this investment. Some of the common reasons for analysis are;
Raw material assurance – analytical testing is employed extensively as part of raw material assurance programmes to ensure compliance with defined specifications and usually applied as part of intake checks. This may include assessment of the quality of ingredients for colour, ripeness (sugar content), weight as well as for safety e.g. microbial pathogens, chemical pesticides or heavy metals and authenticity e.g. meat speciation. In many cases tests may be conducted on a positive release basis whereby batches are not issued to production until clearance has been received for the analytical test undertaken.
In-process verification – this testing is applied to assess the status of material that is in-process and where an understanding of the analytical component is important to the safety or quality of the product. For example, monitoring the pH, acidity or other intrinsic property of a food may be critical for its subsequent safety and stability. This may be equally important for non-foods, for example, cosmetics, household cleaners, and similar formulated products to ensure correct formulation.
Process validation – this testing is applied to validate the efficacy of a process. For example, the cleaning method for production equipment can be assessed to ensure the removal of chemical, microbiological, physical or allergenic contaminants. Alternatively, a process applied to a product to eliminate microorganisms such as pasteurisation or sterilization may be validated by assessing the reduction of microorganisms in or on a product before and after processing (usually conducted in laboratories or pilot plants, if potentially harmful contaminants are being studied).
End product verification – this testing is applied to a product to verify that all of the controls in place during its manufacture have been delivered effectively. It is defined within a Hazard Analysis and Critical Control Point (HACCP) approach for foods but is equally applicable to non-foods insofar as the test provides a degree of assurance regarding control. Testing of this nature is often referred to as ‘end product’ analysis and may be specified in legislation, buying specifications with customers or may be applied by the manufacturer for general assurance purposes of the finished product.
Product development – analytical testing is an intrinsic part of the development process of any product and is applied to ensure that the product will meet defined specifications or, in some cases, it may be exploratory to identify the limits achievable. Examples of testing during product development include conducting stability trials of products to determine the organoleptic, chemical or microbiological shelf life, challenge tests, where contaminants expected to occur during routine production are introduced and their fate determined analytically (in a laboratory) e.g. growth of Listeria monocytogenes in a cooked meat, and compositional analysis to determine the nutritional breakdown of a product for labelling purposes.
Environmental monitoring – analytical testing can be important to assess the presence of harmful microorganisms or chemicals in the environment that may present a risk of contamination to the product or the safety of the worker. In the case of food this may include environmental monitoring for pathogens e.g. Listeria monocytogenes on food contact surfaces such as conveyors, mixing and slicing equipment and storage vessels or non-contact surfaces including floors, walls, drains to ensure the organism is eliminated or controlled to the extent that the risk of cross contamination to foods is reduced. This may also apply to Salmonella species in the environment of infant milk powder production. Environmental monitoring is also critical in non-food applications such as pharmaceutical manufacture to ensure the sterility of clean rooms.
Choice of analytical method
Testing a product is entirely dependent on the availability of an associated analytical method. The choice of an analytical method is often not within the expertise of many industry professionals to determine and therefore it is important to consider a number of factors in association with the laboratory conducting the test.
There are numerous factors to consider and these have been explained in detail in a series of excellent publications from the Institute of Food Science and Technology on Microbiological analysis – key considerations, Chemical analysis – key considerations, Physical analysis – key considerations and Allergen analysis – key considerations. The USFDA also provides excellent supporting resources for laboratory testing.
Uppermost in these considerations are an understanding that the method is capable of detecting or quantifying the analyte of interest in the product / sample matrix, the limit of detection / quantification, the accuracy, precision and measurement of uncertainty.
There are often many different methods available for the same target analyte and the choice of method will be dependent on the specific circumstances. For example, traditional cultural methods for detecting a pathogen such as Shiga toxin-producing E. coli (STEC) in a food involving incubation of the food in a broth to increase the numbers of the organism before plating onto an agar plate to isolate colonies of the organism and subsequent biochemical identification can take many days. This may be suitable for routine verification approaches for raw materials and end products. However, in situations where faster testing is required, enzyme linked immunoassays (ELISA) using immunomagnetic separation of STEC or genomic assays such as the polymerase chain reaction (PCR) can provide much faster detection. However, both of these may yield false positive results and therefore culture confirmation is often needed. Consequently, their use for rapid screening of samples to yield ‘not detected’ results can be useful in such circumstances.
This principle applies to virtually all testing of products and defining the ‘needs case’ for the test can assist in identifying the correct choice of method for the chosen circumstance.
Capability of the laboratory
The majority of tests undertaken are done so in an accredited laboratory. Accreditation ensures that a laboratory has an effective quality system in operation to provide assurance that the analysis is conducted to recognised standards that have been independently audited as part of the accreditation process. In the majority of cases, laboratory accreditation will be to the standard ISO / IEC 17025 Testing and Calibration Laboratories, and audited by a national accreditation body recognised by the International Laboratory Accreditation Cooperation (ILAC). However, other accreditation standards also exist such as the Campden BRI Laboratory Accreditation Scheme (CLAS) and it is also important to recognise that some analyses may be so specialised or state of the art that the laboratory may not be accredited or the method may not be part of the scope of accreditation. In such circumstances it is important to understand the quality systems in operation at the laboratory to ensure the delivery of a reliable result. Considerations for the choice of a laboratory for chemical purposes have also been published by the IFST (How to choose a laboratory for chemical analysis).
Interpretation of the result
In many cases the interpretation of the result is set if it is within the context of legislation or an industry standard for a finished product. This may also be the case for specifications where an agreement has been defined on the criteria to be met as part of a purchase agreement. However, in many cases, the interpretation is often left with the individual or business who undertook the analytical test. For many businesses, expertise in result interpretation may not be readily available and it is essential to ensure that expert advice is sought in relation to any result of a test where an individual is uncertain of the implications. Guidance is available from many organisations in relation to results interpretation. For example publicly available guidance on the implications of microorganisms in foods is available from the Health Security Agency in the UK (Guidelines for assessing the microbiological safety of ready to eat foods placed on the market) and similarly useful guidance is also available from the Institute of Food Science and Technology (IFST). Published standards also generally include defined criteria of acceptance in relation to test results and this is seen in many standards for non-food products. In addition, legislative standards can also provide guidance on process criteria as seen in the EU Regulation on the Microbiological Criteria for Foodstuffs.
When conducting testing for other purposes such as shelf life studies, challenge tests or for highly specialised analyses such as country of origin testing using stable isotope ratio analysis, it is essential that the laboratory providing the analysis provides expert interpretation of the result as failure to understand the implications of a test result that may present a significant risk to the user or consumer is in many cases worse than not testing at all.
Once again an excellent source of further guidance on the interpretation of analytical test results is available from the IFST (Interpreting results – food).
The role of third-party certification programmes and digital software solutions
Analytical testing considerations and the associated laboratory standards are specified in most third party certification programmes such as the BRCGS Global Standards for Food Safety, Consumer Products and Packaging Materials. For example, the Global Standard for Food Safety specifies that “5.6 The company shall undertake or subcontract inspection and analyses which are critical to confirm product safety, authenticity, legality and quality, using appropriate procedures, facilities and standards” and that “5.6.6 Where the company undertakes or subcontracts analyses which are critical to product safety, authenticity or legality, the laboratory or subcontractors shall have gained recognised laboratory accreditation or operate in accordance with the requirements and principles of
ISO/IEC 17025, including proficiency testing where applicable. Documented justification
shall be available where accredited methods are not undertaken.”
Testing of products can involve the development of detailed programmes including test schedules, sampling plans, limits of acceptability, etc. and generate a large amount of analytical data. Digital software can be very helpful in supporting the development and delivery of these programmes and also in determining non-conformances and also trend analysis. The value of a test result is often perceived as whether it passes or fails a specified limit but there is far more insight that can be derived from analytical data in determining broader trends and indicators of process deviations. Systems to support the generation of such insight from data provide significant value beyond that of the test result in isolation.
Summary
Analytical testing is a key element of product assurance processes and this will undoubtedly remain the case in the future. Testing must be carefully considered by industry professionals and programmes should be constantly refined to ensure they continue to serve the purpose they were intended for. Every reader will undoubtedly have come across testing programmes that have been in operation for many years without challenge or review. At best, such approaches are likely to add minimal assurance and at worst they will be providing a costly and false sense of security. If there isn’t a clear decision to be made with a test result it is likely that the test serves little purpose other than to provide the specifier with a false sense of assurance. I hope this article has given you a reminder of the role that analytical testing can play in product assurance together with some of the key considerations for testing.
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AuthorAlec Kyriakides Independent Food Safety Consultant
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