The effectiveness of antimicrobial agents in plastics is determined by microbial resistance testing, particularly for hygiene and sterility-critical industries such as medical devices, packaging, consumer goods, and other related industries. Some of the most prominent standards applying to microbiological tests of antimicrobial and hygienic application are ISO 22196 and ASTM E2180. We are going to discuss here the methodologies of these standards for testing the antimicrobial activity of plastics, outline how they differentiate between these two standards(ISO 22196 vs ASTM E2180), and explain why microbial testing is needed to ensure performance and conformance of such products.
ISO 22196: Exploring its methodology
The standard, known as ISO 22196, has the title ‘Measurement of Antibacterial Activity on Plastics and Other Non-Porous Surfaces’. The reduction in the number of viable bacteria on treated surfaces are measured compared with the reduction on untreated controls, thus establishing the antibacterial properties of plastic materials.
1. Scope and purpose
ISO 22196 standards provide conditions to test the antibacterial activity of antimicrobial-treated plastic surfaces. It lays down requirements for non-porous surfaces and focuses on two types of bacteria, Staphylococcus aureus and Escherichia coli. Therefore, the focal point of the research would be to find out just how well the antimicrobial agent is inhibiting the growth of the bacterial population on the surface in order to ensure the product’s safety and efficacy.
2. Test procedure
In this process, specimens of treated as well as untreated plastics are infected with a standardized suspension of bacteria. A film is placed over the inoculated area so that even contact is made. After inoculation, the specimens are incubated at 35°C for 24 hours under humidity conditions so that bacterial growth occurs. Viable bacteria are recovered and the decrease in the actual count of bacteria from the treated samples compared with the actual counts from the untreated sample is determined.
3. Calculation of antibacterial activity
ISO 22196 applies the logarithmic scale in calculation for the reduction in bacterial count and expressed as antibacterial activity(R). The formula allows the comparison of the count of bacteria right after inoculation (U0), 24 hours after the untreated sample (Ut), and 24 hours after the treated sample (At). The calculated value R of antibacterial activity provides a measure of how effective an antimicrobial agent is.
4. Significance
ISO 22196 standards are extensively used across industries to make sure that the antimicrobial-treated plastics comply with the relevant authorities on antibacterial performance. This test method is particularly significant for medical devices, consumer goods and packaging materials where constant maintenance of surface hygiene must be achieved.
The comparison of ISO 22196 vs ASTM E2180 outlines specific testing methodologies for the manufacturers to choose according to applications of antimicrobial plastic.
ASTM E2180: Understanding its approach
ASTM E2180, known as “Standard Test Method for Determining the Activity of Incorporated Antimicrobial Agents in Polymeric or Hydrophobic Materials.” This test method assesses the antimicrobial activity of incorporated agents into or onto plastic and hydrophobic surfaces. In comparing ISO 22196 vs ASTM E2180, ASTM E2180 methods focus on the incorporated antimicrobial agents that do not leach from the material, thereby reflecting a new approach to testing the activity of antimicrobial-treated plastics.
1. Scope and purpose
ASTM E2180 is intended to quantify the antimicrobial activity of agents absorbed into hydrophobic or polymeric substrates. The test is well-suited for products such as vinyl pool liners, shower curtains and medical devices, in which the agent is incorporated to the substrate and must interact directly with microorganisms to be functional.
2. Test procedure
A mixture of bacterial suspension with agar slurry is applied to the surface treatment and control samples. This approach provides for close contact of bacteria to the surface, as in pseudo-biofilm conditions simulating real situations. The surviving bacteria are recovered and quantified after incubation at 37°C for 24 hours to determine the antimicrobial effectiveness.
3. Quantitative evaluation
ASTM E2180 method is used to measure the bacterial load reduction by expressing the ratio of recovered numbers of bacteria from test surfaces treated and untreated. This test provides immediate as well as long-term efficacies of the applied antimicrobial treatments, which are important to evaluate the durability and performance of exposed products under microbial challenge for some duration.
The assessment of ISO 22196 vs ASTM E2180 hence determines the standard to be followed by the manufacturers for validating the true nature of the antimicrobial properties of plastic products.
4. Applications
ASTM E2180 is highly applicable in assessing the performance of the antimicrobial agent in polymeric materials that are usually exposed wet or in high-humidity environments. It yields a more practical and realistic assessment of how well such agents perform under practical conditions. Hence, the test is handy for consumer goods, healthcare products and water treatment applications.
Comparative analysis: ISO 22196 vs ASTM E2180
Noting that although both ISO 22196 and ASTM E2180 test the antimicrobial activity of plastics, the methods are different as well as the applications, which means that one presents different advantages depending on the material and application.
1. Testing environment
ISO 22196 is performed under static controlled conditions where the bacterial suspension is overlaid as a film to ensure direct contact with the treated surface. On the other hand, ASTM E2180 employs an agar slurry to develop a pseudo-biofilm, allowing a relatively dynamic interaction between the bacteria and the surface that has been treated with antimicrobial agents. This parameter highlights a key methodological difference in ISO 22196 vs ASTM E2180.
2. Material compatibility
ISO 22196 is well suited for smooth, non-porous surfaces where direct contact between bacteria and the antimicrobial agent could easily be held. ASTM E2180 is designed for hydrophobic and polymeric surfaces that often will not allow even distribution of bacterial suspensions due to surface tension problems, thereby making the agar slurry approach more effective.
3. Antimicrobial agent type
ISO 22196 vs ASTM E2180 also diverges in terms of antimicrobial agent focus. Surface-treated materials can be tested under ISO 22196 if the antimicrobial activity is to take place on the outermost surface. ASTM E2180 is specific to agents integrated into the material. Therefore, it only allows for internal activity that cannot leach out.
4. Application relevance
The ISO 22196 test has relevance in applications related to healthcare equipment, food packaging and consumer goods, whereby, mainly, hygienic requirements relate to the surface. ASTM E2180 would be applied on a larger scale for industrial and clinical applications where the environmental conditions are more complex, involving moisture content and load of microbes.
Practical applications and decision-making
The selection between ISO 22196 vs ASTM E2180 method would depend upon the nature of the material and the ultimate application of the product. As an illustration, ASTM E2180 could be preferred by a medical device manufacturer for the long-term antimicrobial performance of a hydrophobic polymer. ISO 22196, on the other hand, may form a basis for the choice by a company manufacturing food packaging to maximize the antibacterial effectiveness of treated plastic surfaces.
1. Industry-specific requirements
Industry-specific requirements are varied. Appreciation of the specific needs of the customer’s industry helps in the choice of test methods so that the product used will meet regulatory standards and function effectively in the intended environment.
2. Product development
At the product development stage, a product is assessed using ISO 22196 and ASTM E2180 tests, which may be valuable in checking the efficacy of an antimicrobial treatment. Inclusion in an early development phase will enable the manufacturer to optimize the antimicrobial formulation so that the finished product meets safety and performance criteria.
Significance in product quality assurance
The most important criteria is ensuring that such plastics are of quality and meet the very requirements of product safety and effectiveness under strict regulatory authorities. The comparison of ISO 22196 vs ASTM E2180 plays a critical role in the validation of the antimicrobial property of plastics.
1. Enhancing consumer safety
The products are expected to fulfill the rigorous standards of ISO 22196 and ASTM E2180 so that they are less likely to become a source of danger to a consumer who may be in touch with harmful microorganisms attached to the product. These are the products coming into direct contact with consumers, like medical devices, food packaging and other consumer products.
2. Supporting product claims
The debate of ISO 22196 vs ASTM E2180 becomes important in the implementation of standards. It enables manufacturers to support claims with respect to their product’s antimicrobial action. Such documentation is important for establishing confidence about a product for consumers and can easily differentiate products in a competitive market.
Regulatory compliance and industry standards
For many industries, compliance with international standards like ISO 22196 and ASTM E2180 is usually a regulatory requirement. These standards provide a benchmark for antimicrobial activity, which has helped manufacturers to comply with legal and safety requirements.
1. Global acceptance
ISO 22196 and ASTM E2180 are internationally accepted, thus being a reliable option for manufacturers seeking international markets. It may even simplify regulatory approval processes, reduce entry barriers and ensure conformity to local and international regulations.
2. Meeting regulatory guidelines
For the healthcare industry, for example, compliance to regulatory standards on antimicrobial efficacy is non-negotiable. ISO 22196 and ASTM E2180 clearly provide testing protocols that ensure that products pass or exceed the requirements as specified by regulatory guidelines for protection to public health and increased access to markets. The selection between ISO 22196 vs ASTM E2180 will therefore thus affect the developments and regulatory approval of antimicrobial-treated plastics.
Conclusion & summary
ISO 22196 and ASTM E2180 are powerful methods for assessing the efficacy of antimicrobial plastics, each tailored to the material and needs of various industries. Therefore, any differences between ISO 22196 vs ASTM E2180 standards will guide manufacturers in determining the right method for validating their products, bringing safety and compliance and, most importantly, consumer confidence. The knowledge of ISO 22196 vs ASTM E2180 is important to make informed decisions.
Microbe Investigations Switzerland (MIS) provides expert testing and validation services tailored to meet the stringent requirements of ISO 22196 and ASTM E2180. Contact MIS today to learn more about our specialized services and how we can help you bring safer, high-quality products to market.
