First Proficiency test will be conducted to assess the technical competence of laboratories in applying EN 13704:2019 standard at SHAPYPRO. This proficiency test, accredited under ISO/IEC 17043, aims to verify laboratories’ technical competence in evaluating the sporicidal efficacy of chemical disinfectants and antiseptics. Proficiency tests are essential to ensure that the methods used meet the highest standards in key sectors such as food, industrial, domestic, and institutional environments.
In addition to providing a standard for measuring the biocidal efficacy of disinfectants and antiseptics, inter-laboratory comparisons promote the quality and reliability of analytical results, allowing laboratories to identify and correct deficiencies in their procedures through statistical tools like the z-score. This improves technical competence, which is particularly critical in combating resistant microorganisms such as bacterial spores, which pose significant challenges to safety and quality across various sectors. The ability to evaluate the biocidal efficacy of these disinfectants and antiseptics plays a crucial role in this context.
Proficiency Test under EN 13704:2019 Standard
EN 13704:2019 standard establishes a quantitative suspension method for evaluating the sporicidal biocidal activity of chemical disinfectants. This method is broadly applicable in food industries, domestic, and institutional areas, specifically excluding medical settings. Its goal is to ensure that disinfectant and antiseptic products have sufficient biocidal capacity to effectively inactivate bacterial spores, organisms whose extreme resistance to adverse conditions and antimicrobial agents makes them a significant challenge.
For a disinfectant to meet the efficacy criteria of this standard, it must demonstrate biocidal activity expressed as a logarithmic reduction of at least 3 log10, equivalent to a 99.9% reduction in the number of viable spores. This level of biocidal activity is crucial, particularly in food processing, where spore contamination can compromise both consumer safety and the quality of the final product.
The reference organisms established in EN 13704:2019 standard for evaluating sporicidal biocidal capacity include species such as Bacillus subtilis (ATCC 6633), Clostridium sporogenes, and Bacillus cereus.
Bacillus subtilis as the Test Organism
Bacillus subtilis is widely used in tests of biocidal activity against spores due to its ability to form highly resistant spores capable of withstanding extreme conditions such as heat, desiccation, and exposure to chemical agents. The standard strain ATCC 6633 allows for the simulation of real-world challenges in industrial and food environments, where bacterial spores pose risks to safety and product quality.
The spores of Bacillus subtilis not only impact product safety but can also compromise production processes, underscoring the need for effective disinfectants and reliable control methods. For testing purposes, the spores of Bacillus subtilis are generated by culturing the bacteria in a medium designed to induce sporulation. After several days of incubation under controlled conditions, the spores are separated from the culture, washed, and microscopically verified to ensure their purity.
Proficiency Test: Testing Conditions
EN 13704:2019 standard defines two possible scenarios for evaluating the sporicidal activity of disinfectants, adapted to practical conditions. Clean conditions use 0.3 g/L of bovine albumin as an interfering substance, representing surfaces with minimal organic matter, while dirty conditions increase the concentration to 3 g/L to simulate more contaminated environments, such as industrial equipment or food processing areas. Tests can be conducted at temperatures ranging from 4°C to 75°C, with contact times varying from 1 to 60 minutes, adjusted to the manufacturer’s specifications to reflect real-world applications.
Proficiency Test: Testing Methods
EN 13704:2019 standard specifies the dilution-neutralization method as the preferred approach for evaluating the sporicidal activity of disinfectants. This method involves exposing a spore suspension to a disinfectant concentration for a defined contact time and then halting the disinfectant’s action at the specified time using neutralizing agents that ensure reliable results. Metrics such as the z-score are used to evaluate the accuracy of results compared to the general average of participants.
When the dilution-neutralization method cannot be applied, the membrane filtration method is used as an alternative, which must also be validated beforehand. This validation ensures that the selected procedures do not interfere with spore viability or affect the disinfectant’s efficacy.
Both methods include controls to guarantee the reproducibility and reliability of results, which are fundamental in tests that evaluate products intended for critical applications.
Efficacy Requirements
Evaluating sporicidal activity under EN 13704:2019 standard requires the precise quantification of viable spores before and after exposure to the disinfectant. Initially, aliquots of the spore suspension are plated on tryptic soy agar (TSA), allowing spores to germinate and form colonies. These colonies, incubated at 30 ± 1°C for 3 days, are counted to determine the initial concentration of viable spores. After the sporicidal test, the process is repeated with the spores exposed to the disinfectant, enabling the calculation of the logarithmic reduction (log10) in the number of viable spores.
Microbiological standard techniques, such as plate counting after proper dilution and disinfectant neutralization, are used for spore counting. Neutralization is essential to stop the disinfectant’s action after the specified contact time, ensuring result accuracy.
According to this standard, a product must demonstrate a logarithmic reduction of at least 3 log10 in the number of viable spores under test conditions to be considered effectively sporicidal, equivalent to a 99.9% reduction of the spores present in the initial suspension.
A critical aspect of the proficiency test is the use of the z-score, a widely recognized statistical tool that allows laboratories’ performance to be assessed in comparison to other participants and pre-established reference values. The z-score measures the standard deviation of the results obtained relative to the average of all participants, providing an objective assessment of the precision and accuracy of the methods used.
A z-score within the acceptable range, typically between -2 and +2, confirms that the laboratory’s methods are technically valid and aligned with international standards, supporting technical competence. The z-score not only confirms that analytical procedures are precise and reproducible but also positions the laboratory as a reliable reference for evaluating the biocidal efficacy of disinfectants and antiseptics.
On the other hand, a z-score outside the established limits may indicate significant discrepancies in the results obtained, suggesting possible inconsistencies in the techniques employed. This type of deviation represents a valuable opportunity to identify specific areas requiring adjustments. The z-score thus serves as a guide for implementing improvements that optimize the quality and reliability of analytical processes.
Participate in Our Proficiency Test
The July 25, 2025, proficiency test will align with EN 13704:2019 standard. This test will include the preparation of a standardized spore suspension (Bacillus subtilis, ATCC 6633), which will be exposed to the disinfectant under controlled conditions. Participating laboratories will receive standardized concentrations of disinfectants, provided by SHAPYPRO, to evaluate their biocidal capacity against spores.
Biocidal active
The protocol will detail specific aspects such as contact time, test temperature, and interfering substances (clean or dirty conditions). This approach will allow participating laboratories to:
- Comply with international regulations: Participation ensures compliance with ISO/IEC 17025 accreditation requirements.
- Identify technical issues: Proficiency test results can reveal deficiencies in employed methods, enabling corrective measures.
- Strengthen customer trust: Participating laboratories will receive a certificate validating their technical competence.
SHAPYPRO will provide the disinfectants and technical specifications for this proficiency test, ensuring a standardized and validated process according to international standards, such as ISO/IEC 17043.
Why Choose SHAPYPRO?
With over 10 years of experience in evaluating the efficacy of disinfectant products, we offer proficiency testing programs that meet ISO/IEC 17043 requirements in compliance with EN 14885:2022/AC:2023..
- We are the only accredited provider globally in this area of testing under ISO/IEC 17043.
- Our expertise allows us to assist clients in developing new methods and R&D projects.
- We manufacture soft diluted soap necessary for both development and testing purposes.
- We offer customized proficiency tests.
- Our tests follow validated international standards and guidelines.
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