Certified Reference Materials (CRM) serve as internal controls to continuously monitor the quality of existing analytical methods and validate/verify new ones. Each CRM is accompanied by a certificate ensuring metrological traceability to the specific target organisms, expected level, and range with a 95% confidence interval.

Eurofins offers CRMs containing multiple target organisms simultaneously. They are available in two formats; powdered or freeze-dried. The powdered format is presented as a set of 5 sachets while the freeze-dried material is presented as a set of 3 vials. Regular testing with these materials, yielding satisfactory results, builds confidence in the laboratory’s ability to consistently produce reliable results. The reference materials are user-friendly, and applicable for both quantitative and qualitative analyses. They serve as a positive control for the method in question, while also serving as negative controls and/or background flora. They can be utilized as a stand-alone test, or they can be added to a chosen matrix. They are ideal for training new analysts.

CRM Detection Tests

The certified reference material is accompanied by a certificate containing crucial information regarding its composition. 

 

Applications

• Daily or regular qualitative or quantitative control
• control of media
• training of staff
• method validation/verification/comparison
• establishing measurement uncertainty

Examples of techniques

• direct counting and dilution
• surface plating
• pour plate methods
• rapid methods
• PCR
• membrane filtration
• chromogenic agars

CRM Certificates

Understanding key points is essential for effective usage of the CRM certificates.

CRM vs. PT

The use of both CRM and proficiency testing (PT) complements each other. According to ISO/IEC 17025, laboratories are required to establish and maintain metrological traceability for their analyses. Both CRM and PT play crucial roles in providing this meteorological traceability.

CRM serves to confirm the satisfactory performance of laboratory methods, ensuring expected results are consistently achieved. This allows laboratories to confidently approve results analyzed for customers on a daily basis. The CRMs contain strains that are characteristic, i.e. strains having the properties that are expected to fit the definition of the target organism. The laboratory itself will assess these results.

Reference cultures

A reference culture typically consists of a single selected strain, providing meteorological traceability to the single strain added, but no quantitative traceability. These cultures can exhibit typical characteristics of the species. For instance, in case of a typical E. coli strain, one would expect it to be gram negative, oxidase negative, ferment lactose and possess β-glucuronidase activity. Conversely, reference cultures may also be atypical for their respective species, such as a strain of Salmonella spp. lacking the ability to produce H₂S. Contact us for detailed list of strains.

On the other hand, PT serves as an external control, where an external provider will assess the performance of the laboratory. At the time of analysis of a PT trial, the laboratories are unaware of the target organisms present in these samples, simulating real-life customers' samples. This enables laboratories to assess their ability to detect sample contents and compare their results with those of other laboratories around the world. PT also provides insights into different methodologies, allowing laboratories to benchmark their methods against competitors’. Challenges posed by PT include detecting atypical strains and the ability to detect low or high levels of target organisms.

In summary, CRM is indispensable for internal control and verification purposes. PT serves as a vital external control, enabling laboratories to benchmark their quality against others in the field.

About

Eurofins Food & Feed Testing Norway AS provides certified reference materials produced accredited at IFM Quality Services Pty Ltd, in Australia. The production complies with the requirements of EN ISO/IEC 17034; General requirements for the competence of manufacturers of reference materials. IFM holds accreditation from the American Association for Laboratory Accreditation (A2LA), certificate number 3189-03. Certified reference materials produced accredited under ISO/IEC 17043 have metrological traceability.

Contact

CRMs available:

CRM	Purpose	Format	Set	Target organisms	Examples of analysis
MV0026	Universal control, for water and food	Freeze-dried	3 vials	Bacillus cereus Clostridium perfringens Enterococcus faecalis Escherichia coli Klebsiella aerogenes Pseudomonas aeruginosa Aeromonas hydrophila*)	Plate count, Enterobacteriaceae, coliform bacteria, thermotolerant coliform bacteria, E. coli (quant/qual), enterococcus (water/food), C. perfringens, anaerobic sulfite reducing bacteria, P. aeruginosa, presumptive Bacillus cereus
FM0046	Pathogen control	Powder	5 sachets	Listeria monocytogenes Salmonella Hofit	Quantitative or qualitative
FM0030	Hygiene control - coliforms, mould and yeast	Powder	5 sachets	Klebsiella aerogenes Escherichia coli Aspergillus niger Candida utilis	Plate count, Enterobacteriaceae, coliform bacteria, thermotolerant coliform bacteria, E. coli, mould, yeast
FM0031	Gram positive control	Powder	5 sachets	Bacillus cereus Lacticaseibacillus rhamnosus Staphycococcus aureus	Plate count, presumptive Bacillus cereus, lactic acid bacteria, coagulase positive Staphylococcus
MV0037	Legionella control	Freeze-dried	3 vials	Fluoribacter bozemanae Legionella pneumophila SG1	Legionella total, Legionella spp., Legionella pneumophila SG1

*) background flora only