ASTM Methods

     When using our products, it is important to have an existing experimental framework. Having well established and widely accepted methods in place is one of the most important aspects of our biofilm reactors. In this post, we’ll explain what the ASTM standard methods associated with the CDC, Rotating Disc, and Drip Flow Biofilm Reactors refer to.

     ASTM International, formerly The American Society for Testing and Materials is an organization dedicated to crafting and implementing standards to ensure products of consistent quality around the world. These standards consist of specifications, test methods, and classifications, all crafted to create a consistent measure for the quality of a product. The standards focus on a variety of products and tests, from the specification of structural steel alloys to the methods our products assist in, the quantification of biofilm growth and the efficacy of disinfectants.

     Our CDC, Rotating Disc, and Drip Flow Biofilm Reactors are each have at least one standard method associated with them.  The use of these reactors in experiments helps ensure that research done with the same reactors will have consistent results between experiments. This consistency allows the reactors to be used as the standard which both researchers and the ASTM Standard Test Method use in evaluating biofilm growth on a variety of surfaces and in the CDC Biofilm Reactor’s case, the efficacy of disinfectants on those biofilms.

     The CDC Biofilm Reactor is used in two standard methods, ASTM E2871-13 and E2562-12. The first (E2871-13) refers to quantifying biofilm growth, specifically Pseudomonas aeruginosa (P. aeruginosa). The CDC Biofilm Reactor is a continuously stirred tank reactor (CSTR) that facilitates the growth of biofilms on sample surfaces (referred to as coupons) held in place by the reactor. The test method describes how to use, sample, and analyze the biofilms growing on the coupons. Following the standard method using this reactor ensures reproducible and accurate results for all research done under the same conditions.

     The second ASTM standard method for the CDC Biofilm Reactor (E2562-12) builds off the previously described method, and provides a means for evaluating efficacy of disinfectants against biofilms, again specifically P. aeruginosa.  This method describes how to grow, sample, analyze and compare biofilms treated with disinfectants with untreated control biofilms. Using this standard method, the efficacy of given disinfectant is reported as how the number of viable or colony forming cells (CFUs) is reduced by factors of ten (log10). By testing a disinfectant using a standard method, researchers are able to quantitatively find the efficacy of a variety of disinfectants in a manner that is both accurate and reproducible.

     The next method, ATSM E2196-17, uses our Rotating Disk Biofilm Reactor. This reactor, a CSTR like the CDC Biofilm Reactor, produces higher shear conditions to evaluate how well biofilms grow in a steady state higher shear environment, like those one might find in pipes, streams, or even blood vessels. The method uses P. aeruginosa like the CDC methods, and similarly the methods of sampling and quantification of biofilm growth are explained.

     In contrast to the Rotating Disk Biofilm Reactor method, this final method evaluates biofilm growth under low shear conditions using our Drip Flow Biofilm Reactor. This method, ASTM E2647-13, uses P. aeruginosa yet again, and consists of a short period of batch growth followed by longer period of steady state growth. This, as well as the previous method, allows researchers to evaluate the effects that shear has on the growth of biofilms in a repeatable and consistent fashion.

     ASTM standard methods allow for reproducibility and consistency across many fields, allowing manufacturers and researchers alike to ensure reliable and reproducible products, studies, and literature.