Disinfectants tests

Disinfection tests can be classified according to the test organism, ie, whether the test employs certain species of bacteria, fungi, or vimses classified as to whether it is a static test or a cidal test, as in a bactericidal vs bacteriostatic test or sporicidal vs sporistatic test or classified as to whether it is a microbial reduction test or an end-point test where all the organisms in the test are apparently killed. Procedures may be distinguished by in vitro or in vivo testing. Another way to consider tests is whether they are screening tests, practical type laboratory tests, or field tests. 

Croshaw B. (1981) Disinfectant testing—with particular reference to the Rideal-Walker and Kelsey-Sykes tests. In Disinfectants Their Use and Evaluation of Effectiveness (eds C.H. Collins, M.C. Allwood, S.F. Bloomfield A. Fox), pp. 1-15. London Academic Press. 

Unfortunately, standardization of the methodology to be employed in these efficacy tests has proved difficult, if not impossible, to obtain, as has consensus on what level of killing represents a satisfactory and/or acceptable result. It must be stressed however, that unlike tests involving chemotherapeutic agents where the major aim is to establish antimicrobial concentrations that inhibit growth (i.e. MICs), disinfectant tests require determinations of appropriate cidal levels. 

DDIC ELV-12 DC 1 1 400 disinfection tested in pilot plant 0.2 100,000 0.15US ... 

The effectiveness of disinfectants should also be evaluated. The approach to this is not as simple as it might seem. Very obviously, the simplest method is chemical analysis of the active ingredient. However, it is usual to find that this is supplem ted by some form of microbiological data. The principles of microbiological testing of disinfectants go back to the Rideal-Walker method of 1903 and probably earlier. Even with this long history, disinfectant testing is not free, nor ever has been free, from criticism and controversy. 

Bloomfeld SF, Arthur M, Gibson H, Morley K, Gilbert P, Brown MRW (1995) Development of reproducible test inocula for disinfectant testing. Int Biodeterior Biodegrad 36 ... 

SWB Newsom, C Rowland. Application of the hygienic hand-disinfection test to the gloved hand. J Hosp Infect 14 245-247, 1989. 

Johnston, M. D. and Jones, M. V., 1995. Disinfection tests with intact biofilms combined use of the Modified Robbins Device with impedance detection. Journal of Microbiological Methods 21, 15-26. 

Lambert, R. J., Johnston, M. D. and Simons, E.-A., 1998. Disinfectant testing use of the bioscreen microbiological growth analyser for laboratory biocide screening. Letters in Applied Microbiology 26, 288 292. 

Lambert, R. J., and van der Ouderaa, M.-L. H., 1999. An investigation into the differences between the bioscreen and the traditional plate count disinfectant test methods. Journal of Applied Microbiology 86, 689 94. 

In the United States, several tests using bacteria as the test organisms have been adopted as standardized methods. The primary test used is the use-dilution method from the AOAC (Association of Official Analytical Chemists). The American Society for Testing and Materials (ASTM) has also developed virucidal test procedures. In western Europe, disinfection tests are published as national standards in France (AFNOR), the United Kingdom (BSI), and Germany (DIN). 

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