In June 2023, MicroVal has approved the issuing of the certificate for MCS Diagnostics’ CertaBlue YM test for the detection of Yeast and Mold. WFC Analytics has carried out the validation study of this rapid method, based on ISO 16140-2:2016, for the scope of broad range of foods (except cooked poultry products).
The CertaBlue YM test is designed to rapidly detect yeast and mold contaminations. An inoculated vial is placed into the AutoScanner System, where it is incubated and monitored in real time. If growth is detected, the sample fails; if there is no detection, the sample passes (i.e., the counts are below the specification limit).
The reference method, ISO 21527-1:2008, for the enumeration of the level of microorganisms was used in this validation to establish if levels of microorganisms exceed the defined threshold of 1 cfu per g for liquid products and 10 cfu per g for other products. Thus, a qualitative presence/absence approach with a set presence/absence limit was used, where presence of a single colony (solid and semi-solid products always require a 1:10 dilution step) was equivalent to a “detected” result and absence of a single colony was equivalent to a “not detected” result.
The summary report of this validation study, together with the resulting certificate, , number 2021LR95, can be found on the MicroVal website under ‘issued certificates / alternative methods’.
MicroVal has approved the issuing of the certificate for ThermoFisher Scientific’s SureTect Salmonella Species PCR Assay. Q Laboratories carried out the extension validation study for a broad range of foods in which the use of pre-warmed (41.5 or 37 ± 1 °C) BPW ISO as the primary enrichment media was evaluated, in addition to alternative sample sizes.
The Thermo Scientific SureTect Salmonella Species PCR Assay was originally validated by AFNOR according to the ISO 16140:2003 standard in 2013. Multiple extension studies were conducted since the initial validation study, and the first renewal validation enabled alignment with the revised ISO 16140 – 2:2016 standard in 2017. The method is validated for the use of three instruments: Applied Biosystems 7500 Fast, Applied Biosystems Quantstudio 5 and the PikoReal instrument. A summary of the initial validation, original renewal, and previous extension studies can be found on the available summary report (AFNOR Certificate: UNI 03/12-01/18).
All data generated from the three claimed thermocyclers for each matrix claimed under the AFNOR Certificate: UNI 03/12-01/18 was presented in a Gap Analysis report to the MicroVal Technical Committee (MVTC) according to the MicroVal Rules set up by the MicroVal General Committee (MGC). The MVTC agreed that the supporting data on the three different cyclers covered a broad range of foods, thus meeting the MicroVal requirements needed for the method to be transferred to become MicroVal 2022LR111. It should be noted that both Applied Biosystems 7500 Fast and QuantStudio 5 thermocyclers are included in the extension claims in opposite to the PikoReal instrument that was used in the ILS portion of the original validation.
The summary report of the extension validation study, available on the MicroVal website, provides an overview of the categories and sample sizes that were included in the final scope, as well as the instrumentation that was validated for use in this extension. The certificate and the accompanying summary report, number 2022LR111, can be found under ‘issued certificates / alternative methods’.
MicroVal has approved the issuing of the extended certificate for Millipore Sigma’s Assurance GDS for Cronobacter Tq II. Campden BRI carried out the extension study for a new confirmation method in combination with two different isolation methods. The Assurance GDS for Cronobacter Tq II method was previously validated in December 2018 for infant formula and infant cereals and environmental samples for 10-375 g samples.
The Assurance GDS for Cronobacter Tq II is an automated nucleic acid amplification system for the detection of Cronobacter in infant nutritional formula, ingredients, and environmental samples. This PCR-based method targets DNA specific to Cronobacter spp.
The extension study followed the MicroVal interpretation guidelines for ISO 16140-6 for a new confirmation method from a previously validated qualitative method. This extension configuration was previously validated in the Assurance GDS for E. coli O157:H7 Tq, where an inclusivity and exclusivity study and a limited number of sensitivity samples were used to assess the performance of the new confirmation method. In the extension study, samples were analysed by the alternative method only to verify the performance of the new colony isolation and colony confirmation procedures.
Confirmation of presumptive positive colonies was performed using two different isolation methods:
Direct streak of the 1:10 enriched sample onto one chromogenic agar plate from a choice of 3 different isolation media
Aliquot the remaining GDS concentration reagent retained in the resuspension plate onto one chromogenic agar plate from a choice of 2 different isolation media
A selection of infant formula, infant cereals and dried milk products were tested in the sensitivity study as a representative number of the samples listed in the validation.
The certificate and the accompanying summary report, number 2017LR77, can be found under ‘issued certificates / alternative methods’.
MicroVal has approved the issuing of the certificates for Bentley’s BactoCount IBC 3.0 and BactoCount IBCm 3.0. ACTALIA Cecalait carried out the validation study for the enumeration of somatic cells and total bacterial count for the scope of raw cow’s milk.
The BactoCount IBC 3.0 and BactoCount IBCm 3.0 are fully automatic instruments that implement flow cytometry for a real-time and accurate analysis of total flora and somatic cells in raw milk. Although both instruments can run the analysis for somatic cell count and total bacteria count simultaneously, for this validation both applications were tested separately.
The results of the validation, performed according to the ISO 16140:2:2016, demonstrate that the performance characteristics of both instruments for the enumeration of somatic cell count comply with the values specified in ISO 8196-3 / IDF 128-3. Based on the ISO 13366-1: 2008, both BactoCount instruments were compared and revealed at least equivalent with the SomaCount FC as the reference method.
For total bacterial count, the validation also resulted in compliance of the performance characteristics with the values defined in ISO 16297. Based on the ISO 4833-1: 2013, the comparison study with the BactoCount 2.0 as the reference method revealed at least equivalent and is approved as compliant with the criteria of the EURL MMP document for enumeration of total flora (2011).
The certificates and the accompanying summary reports, number 2021LR97 for BactoCount IBC 3.0 and number 2021LR98 for BactoCount IBCm 3.0, can be found under ‘issued certificates / alternative methods’.
MicroVal is an international organisation for the validation of alternative methods in food and water microbiology. The basis for these validation studies is the ISO 16140 series. The first MicroVal certificate dates back from 2007. Since then, more than 70 test kits and methods by manufactures in North America, Asia and Europe, have been successfully validated and resulted in a MicroVal certificate.
Recently, there has been an increase in the demand for the validation of methods for milk analysis and more specifically somatic cell count and total bacterial count. These studies require additional validation based on IDF standards (e.g. ISO 8196, ISO 13366, ISO 16297). Therefore, MicroVal will establish a working group that specifically focusses on these validation studies. In order to start this working group, MicroVal is looking for experts with experience and knowledge of methods for milk analysis (cow, sheep, goat, etc.) and the relevant ISO standards.
Experts who’s experience matches with the requirements below, are invited to apply for joining the MicroVal team.
Keep up to date with newly developed methods for milk analysis;
Involvement with the validation processes and evaluation of test results;
Knowledge of the use and performance of new methods based on their method validation;
Be part of an international network, consisting of manufacturers, researchers and standardization/validation experts, contributing to the quality assurance of analytical methods.
Fluent in English.
General scientific training in (dairy) microbiology;
A minimum of five years of recent experience in an organization involved in food/dairy microbiology, including working within an ISO 17025 accredited quality management system;
Knowledge and experience in working with ISO reference methods for somatic cell count and total bacterial count, such as:
ISO 13366-1| IDF 148-1
Milk – Enumeration of somatic cells – Part 1: Microscopic method
Microbiology of the food chain – Horizontal method for the enumeration of microorganisms – Part 1: Colony count at 30 °C by the pour plate technique
Microbiology of the food chain – Horizontal method for the enumeration of microorganisms – Part 2: Colony count at 30 degrees C by the surface plating technique
Knowledge and experience in method validation and validation standards, such as:
ISO 8196-3| IDF 128-3
Milk – Definition and evaluation of the overall accuracy of alternative methods of milk analysis — Part 3: Protocol for the evaluation and validation of alternative quantitative methods of milk analysis
ISO 13366-2| IDF 148-2
Milk – Enumeration of somatic cells – Part 2: Guidance on the operation of fluoro-optoelectronic counters
ISO 16297| IDF 161
Milk – Bacterial count — Protocol for the evaluation of alternative methods
ISO 21187| IDF 196
Milk — Quantitative determination of microbiological quality — Guidance for establishing and verifying a conversion relationship between results of an alternative method and anchor method results
The following is expected from the experts joining the MicroVal team for the validation of methods for milk analysis:
Contribute to the reviewing work, which consists of:
Reviewing of protocols and reports of ongoing validation studies;
Reviewing of modifications and extension studies;
Evaluation of certificate renewal requests;
Participate in online two-hours meetings, which take place max. 4 times per year;
Contribute on a voluntary basis as MicroVal is a non-profit organisation;
Maintain confidentiality – a non-disclosure agreement is signed by all MicroVal members.
Interested candidates are invited to submit their application, containing the following information:
A recent resume including supporting information on meeting the above requirements;
Applications can be sent to email@example.com before March 15th, 2023. Also questions concerning the application procedure can be sent to the email above. More information about MicroVal and its procedures can be found in the MicroVal Rules, the certification scheme of MicroVal. The MicroVal secretariat is run by NEN, the Royal Netherlands Standardization Institute.
MicroVal has approved the issuing of the certificate for Check-Points’s Check&Trace Salmonella 2.0. WFC Analytics carried out the validation study, based on ISO 16140-6, for an alternative method for the confirmation and typing of Salmonella spp. Following from the validation study, the Check&Trace Salmonella 2.0 (CTS 2.0) is considered equivalent to the reference method (ISO 6579-1 and ISO 6579-3) for the confirmation of presumptive Salmonella spp. isolated on non-selective NA and selective XLD and for typing of 59 Salmonella serovars.
The Check&Trace Salmonella 2.0 Assay is a qualitative, semi-automated real-time PCR test designed for the confirmation and typing of presumptive Salmonella isolates from enriched culture media. The confirmation procedure advances a suspected (presumptive) Salmonella result to a confirmed Salmonella spp. result or a Salmonella negative result. The typing procedure generates a serovar result or a “genovar” code both uniquely defining each bacterial isolate tested.
DNA typing differs from serotyping. With serotyping the presence of antigens on the cell surface and flagella are detected. This is based on expression of genes located on two specific segments of the Salmonella genome. The CTS 2.0 assay detects genetic variation at 21 loci scattered over the whole Salmonella genome: this generates specific Salmonella genotypes, also called Genovars. The CTS 2.0 database links Genovars to a collection of well-characterized Salmonella Serovars. A Genovar will be given as test result if there is no established Serovar for the Genovar generated by the CTS 2.0 assay.
Check&Trace Salmonella 2.0 is considered equivalent to the ISO standard (ISO/TR 6579-3:2014) for typing of 59 Salmonella serovars. The full list of Salmonella serovars is given in the certificate and validation report, available on the MicroVal website under ‘issued certificates / confirmation methods’.
In December 2022, MicroVal has approved the issuing of the renewed certificate for Bio-Rad’s iQ Check STEC VirX, based on the extension validation study to include food products based flours and raw doughs within the scope. Like the initial validation study, also the extension study was carried out by ADRIA Développement.
The iQ-Check STEC VirX for real-time PCR detection of virulence genes in Shiga toxin-producing Escherichia coli has now been validated for raw dairy products, raw meat products (excluding poultry) and flours and raw doughs. In general, this method gives the results for both stx and eae genes, however for this validation study, the interpretation was based on detection of stx only.
The certificate and the accompanying validation report, number 2021LR96, can be found under ‘issued certificates / alternative methods’.
In September 2022, MicroVal has approved the issuing of the certificate for MCS Diagnostics’ CertaBlue TVC for the detection of Total Viable Count. WFC has carried out the validation study of this rapid method, based on ISO 16140-2:2016, for the scope of broad range of foods and environmental samples. To obtain the broad range of foods claim, the following categories were included in the validation study:
Milk and dairy products (raw and heat-processed)
Meat and meat products and poultry and poultry products (raw, ready-to-cook and ready-to-eat, ready-to-reheat)
Ready-to-cook fish and seafoods and ready-to-eat, ready-to-reheat fishery products
Processed fruits and vegetables
Bakery products and multi-component foods or meal components
The CertaBlue TVC test is designed to rapidly detect microbial contaminations. An inoculated vial is placed into the AutoScanner System, where it is incubated and monitored in real time. If growth is detected, the sample fails; if there is no detection, the sample passes (i.e., the counts are below the specification limit).
In the validation study, the CertaBlue TVC has been compared to the ISO 4833-1:2013. Although the reference method is generally used to enumerate the level of microorganisms, in this validation it was used to establish if levels of microorganisms exceed the defined threshold of 1 cfu per g for liquid products, 1 cfu per swab for swabs and 10 cfu per g for other products. Thus, a qualitative presence/absence approach with a set presence/absence limit was used, where presence of a single colony (solid and semi-solid products always require a 1:10 dilution step) was equivalent to a “detected” result and absence of a single colony was equivalent to a “not detected” result.
The certificate and the accompanying summary report, number 2021LR94, can be found on the website under ‘issued certificates / alternative methods’.
MicroVal has recently issued the certificate for Neogen’s Soleris Commercial Sterility Testing Vials (NF-105) for the determination of commercial sterility in UHT treated milk and dairy alternative plant drinks. These are ready-to-use media vials containing a broth able to grow aerobic, mesophilic microorganisms (bacteria, yeasts and moulds) that are able to grow on an aerobic plate count at 30°C. Results from the validation data showed that the alternative method can be used as a rapid and sensitive testing method for commercial sterility monitoring of UHT treated milk and dairy alternative drinks.
Campden BRI has carried out the validation study of this alternative method, based on ISO 16140-2:2016. The Soleris NF-105 testing vial has been validated against the Codex Alimentarius, Code of Hygienic practice for milk and milk products (CAC/RCP 57-2004), Annex B Microbiocidal control measures Section 2.2 process management for UHT treatment using ISO 4833-1:2013 for the plate count at 30°C. In this validation, the method was used to determine a defined threshold of product contamination of greater than ≤ 10cfu per 0.1ml as defined in the European Directive 92/46 annex C chapter 2 for ultra-high temperature (UHT) milk.
The certificate and the accompanying summary report, number 2021LR100, can be found under ‘issued certificates / alternative methods’.
In June 2022, MicroVal has approved the issuing of the certificate for Bio-Rad’s iQ-Check™ STEC VirX kit for real-time PCR detection of virulence genes in Shiga toxin-producing Escherichia coli. ADRIA Développement has carried out the validation study of this alternative method, based on ISO 16140-2:2016, for the scope of raw meat products (excluding poultry) and raw dairy products.
STEC outbreaks are commonly associated with the consumption of raw meat, particularly beef, but also with dairy products. A sample positive for both stx1/stx2 and eae targets typically requires further testing for the identification of the major E. coli serogroups. The iQ-Check STEC VirX Kit, based on a multiplex real-time PCR system, allows the detection of the stx1/stx2 and eae virulence genes within a few hours after microbiological enrichment.
The certificate and the accompanying validation report, number 2021LR96, can be found under ‘issued certificates / alternative methods’.