First MicroVal certificate for MCS Diagnostics’ CertaBlue detection method

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’.

First MicroVal certificate for commercial sterility detection method

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’.

MicroVal Expert opinion about AOAC Validation Coronavirus Test Kits

AOAC INTERNATIONAL announced that it has issued five certificates of validation for proprietary test kits that detect SARS-CoV-2 on stainless steel surfaces. These test kits have passed the evaluation required by the globally recognized AOAC Research Institute’s Performance Tested Methods (AOAC-PTM) Program, which implemented an Emergency Response Validation (ERV) process to accelerate the evaluations. The MicroVal experts have evaluated the approaches taken by the AOAC-PTM validation program for detection methods of the SARS-CoV-2 on environmental surfaces, and fully support this AOAC initiative.

Below you can find some more information from AOAC on this program.

The COVID-19 crisis has fundamentally changed our way of life and the everyday life in the professional and domestic environments. It is obvious this will have other impacts in the future.

SARS-CoV-2 is a public health issue. Direct transmission of the virus from person-to-person is the main route of contamination. However, some food industries have faced contamination issues among co-workers[1]; stability of SARS-CoV-2 on various surfaces have been demonstrated[2], and transmission of the virus from contaminated surfaces might be possible[3].

Emergency responses were set up to support the food industry. Methods have been developed to detect SARS-CoV-2 in food production environment to evaluate the efficiency of control measures designed to eliminate the virus from surfaces. AOAC INTERNATIONAL has activated an accelerated program to evaluate test kits for detecting coronavirus on surfaces.

For food manufacturers, contract laboratories, and others in the food supply chain, the certifications provide independently validated tests they can use to ensure their

sanitation protocols are effective and to provide a culture of safety for their essential employees.

The AOAC Performance Tested Method program (PTM) includes multiple steps:

  • An in-silico analysis was developed to evaluate the quality of the primers and probes of the test kits. This innovative approach in the framework of method validation makes sense as thousands of SARS-CoV-2 genomes are free available, and the databases continue to expand.  In the validation study, there were 15,764 accessions evaluated for inclusivity, and 65 near neighbors and environmental background organisms for exclusivity.
  • The matrix study was run with stainless steel test areas inoculated with intact SARS-CoV-2 virus (USA_WA1/2020). The samples were prepared by a single independent laboratory. After proper surface sampling, the US Centers for Disease Control and Prevention (CDC) method and the candidate method were run in an unpaired data study design to attempt to detect the virus on the surfaces. The acceptability of the alternative method is evaluated by the Probability of Detection approach[4].
  • The Robustness, Product Consistency and Stability studies will be run in a final step early 2021, as kits from different production batches are required. Robustness parameters evaluated will be specific to each method.

The involved AOAC reviewers are recognized experts in the field.

AOAC Volunteer Expert

William Burkhardt, FDA/CFSAN/OFS/DSST

AOAC Expert Reviewers


Efi Papafragkou, FDA/CFSAN/OARSA

Sanjiv Shah, EPA/ORD/HSMMD

John SantaLucia, Wayne State University

Chengzhu Liang, Qingdao Customs District Laura Rose, CDC/DDID/NCEZID/DHQP





Renewed and extended certificate for Assurance GDS E. coli 0157:H7 Tq

In October 2020, MicroVal has approved the renewal and extension of the certificate for Assurance GDS E. coli 0157:H7 Tq, manufactured by Merck MilliporeSigma. This genetic detection system is an automated nucleic acid amplification system for the detection of pathogenic E. coli 0157:H7 in foods, ingredients and environmental samples. The renewal and extension study was conducted by Qlaboratories.

The Assurance GDS E.coli 0157:H7 Tq was first validated in 2016. For the renewal project, all data was reanalysed according to the statistical guidelines outlined in ISO 16140-2:2016 to determine if the acceptance criteria were met.

An additional alternative confirmation method for E. coli O157:H7 was also added to the scope. Necessary supplemental testing was conducted following a sensitivity outline for the categories that are already claimed following ISO 16140-6: 2019.

The renewed and extended certificate, registered as study number 2015LR49, can be retrieved form the MicroVal website, together with the supporting validation report.