Importance of Certified Reference Materials

In addition to their importance in the quality assurance of food testing personnel and procedures, CRMs are essential for the internal quality control of routine food analyses. Because the performance of food testing methods can vary between laboratories due to technical and human factors, variations in the recovery of microbial contaminants or specific analytes, or the unpredictable nature of microorganisms, the use of homogenous internal controls, such as CRMs, can be employed to help demonstrate the credibility of analytical results and the comparability of results from different laboratories. This is particularly true for standard procedures designed for the microbiological analysis of food products; often, these procedures are designed for one specific strain and may not be applicable toward the detection or quantification of other microbial species.

Currently, biological and chemical CRMs are available from both official and commercial manufacturers that are ISO Guide 34:2009 accredited, such as ATCC and LGC Standards. For CRMs specifically used in food testing, preparations can be obtained as either an inoculated (where applicable) and standardized preparation of a specific food material, or as a preserved and defined preparation that can be used to inoculate or fortify various food preparations. This latter format, in particular, is useful in that it allows the user to inoculate a known quantity of the defined CRM into an appropriate food matrix that resembles the routine samples as much as possible. This format allows for testing the influence of matrix constituents, which can significantly affect the accuracy of measurements in microbial, biochemical, and chemical analysis of food. For microbiological CRMs, this format also allows for testing competitive microbial strains as well as the development and validation of growth media and species specific test methods.

Overall, the contamination of food poses a significant health burden on the human population that is largely preventable and frequently under-reported. By urging food testing laboratories to gain accreditation, and consequently, employ the use of CRMs for quality assurance and as internal controls in food testing procedures, we can be confident that the results generated from food testing analyses are high quality and reliable. In turn, this will help strengthen the food safety system by contributing to the prevention of foodborne outbreaks and the integrity and quality of food.

Dr. Wilder is a technical writer at ATCC. Reach her at [email protected]. Gormley is product manager at LGC Standards.

References

1. World Health Organization. Foodborne ­Diseases, http://www.who.int/topics/foodborne_diseases/en/, 2014.
2. Food and Drug Administration. Food Safety Modernization Act (FSMA) Fact Sheets & Presentations, http://www.fda.gov/Food/GuidanceRegulation/FSMA/ucm247546.htm, 2014.
3. Food and Drug Administration Food Safety Modernization Act; Public Law 111-353, http://www.gpo.gov/fdsys/pkg/PLAW-111publ353/pdf/PLAW-111publ353.pdf, 2011.
4. Food Safety and Inspection Service. Establishment Guidance for the Selection of a Commercial or Private Microbiological Testing Laboratory, 2013.
5. Coffman, V., Plunkett, D., Wilson, G. & Warren, W. The Food Safety Modernization Act – A Series on What is Essential for a Food Professional to know. Article 7. Laboratory Accreditation. Food Protection Trends, 44-48, 2014.
6. ISO/IEC 17025:2005 – General requirements for the competence of testing and calibration laboratories, 2010.
7. Encyclopedia of Food Microbiology, Second Edition. Elsevier, 2014.
8. In’t Veld, P. The use of reference materials in quality assurance programmes in food microbiology laboratories. International Journal of Food Microbiology, 45: 35-41, 1998.