Importance of Certified Reference Materials

Foodborne illnesses pose a significant economic and public health burden associated with product recalls, epidemiological tracking, extensive healthcare expense, and countless numbers of hospitalizations and deaths. The global sourcing of raw materials and distribution of products combined with the differences in regulations of agrochemicals and medicines mean that the contamination of food can also impact international trade. For food producers in the U.S., the FDA Food Safety Modernization Act (FSMA) has made identifying and tracing foodborne adulterants in raw and processed food products throughout the manufacturing process a matter of public law. However, as many food products are complex systems, it can be challenging to identify biological, chemical, and environmental adulterants, as well as discriminate between those that are harmful from those that are not harmful. Thus, the use of highly characterized, homogenous, authenticated control materials, such as certified reference materials (CRMs), is imperative in food testing.

Food products and raw materials can become contaminated during any stage in the process of food production to consumption, or “farm to fork.” These contaminants can be biological, chemical, or environmental in nature, encompassing microorganisms, radiological hazards, natural toxins, drug residues, pesticides, harmful chemical reagents, allergens, parasites, and adulterants originating from soil, water, industry, and animals. When consumed, these contaminants may result in gastrointestinal symptoms such as abdominal cramping, nausea, vomiting, diarrhea, and dehydration. Depending on the causative agent of the foodborne illness, other neurological, gynecological, or immunological symptoms can present, which may lead to multi-organ failure, contributing to a high incidence of mortality.

In an effort to update U.S. food safety laws, FSMA was enacted in 2011, which provided a legislative mandate to require preventative control protocols and comprehensive reference materials to identify contaminants throughout the manufacturing process, as well as the authority to prevent intentional adulteration. The FDA now has oversight to ensure compliance with these aforementioned regulations, including mandated inspections, access to the records of food manufacturing facilities, requiring certain food testing to be carried out by accredited laboratories, and the ability to develop a program that enables laboratories to become accredited.

Emphasizing Accreditation

While several local, state, and federal government food testing laboratories have already pursued accreditation programs such as ISO/IEC 17025:2005, the accreditation of commercial laboratories is still in its formative years. While accreditation is not yet required, it is emphasized by FSMA as it offers a means to support the generation of reliable and traceable data that is consistent among food testing laboratories. Similarly, a recent guidance document released by the USDA Food Safety and Inspection Service (FSIS), entitled Establishment Guidance for the Selection of a Commercial or Private Microbiological Testing Laboratory, suggested that accreditation under ISO/IEC 17025:2005 helps to increase confidence in the accuracy of test results produced by a laboratory. Largely, accreditation ensures that all laboratory results are achieved through the proper obtainment and preparation of samples, the employment of scientifically sound testing methods and reference standards, and ethically-responsible, competent laboratory personnel. In turn, this provides additional confidence that a minimum standard of quality has been met throughout the food testing process.

Laboratories that are ISO/IEC 17025:2005 accredited require the use of CRMs when using reference standards for traceability; Section 5.6.3.2 of this guideline states, “reference materials shall, where possible, be traceable to the international system of units of measurement, or to certified reference materials.” Essentially, these materials are biological or chemical measurement standards that are homogenous and stable with respect to one or more specified property and for which traceability and values of uncertainty at a stated level of confidence are established, where applicable. CRMs are produced under an ISO Guide 34:2009 accredited process to offer confirmed identity, well-defined characteristics, and established chain of custody, making them highly effective as standards in research and development as well as laboratory testing. Moreover, they are accompanied by a certificate that provides the value of the specified property, the expiration date, and the proper use, thus confirming that the necessary procedures have been carried out to ensure both validity and traceability.

CRM Practicality

Presently, a number of CRMs have been developed for use by ISO/IEC 17025:2005 accredited food testing laboratories for the analysis of quality assurance and product safety. For quality assurance, CRMs are frequently used for method validations, such as the calibration of laboratory equipment or the examination of new identification, detection, or cleaning methods. This form of testing is needed to assess the quality of the measurement results as well as to demonstrate their traceability to a stated reference. CRMs are also used to evaluate the performance of laboratories and laboratory personnel through proficiency testing. The primary aim of this latter form of testing is to enable laboratories to monitor their performance for the detection and quantification of a given analyte or contaminant, and compare it with that of their peers. Moreover, it provides information to participants on any technical issues and methodologies relating to the testing of food products. Essentially, the use of CRMs in quality assurance testing helps to ensure that the data generated by a particular food testing laboratory is consistent, high quality, reliable, and traceable.