science in cleaning Scientific assessment of the enemy This lack of appreciation for the detailed nature of surface contamination is under-standable: The basic analytical understand-ing of how non-microbial contamination interacts with surfaces is a development of the last 70 to 80 years. It is now known that in some cases microbial and non-microbial particles as well as other contaminating substances are held to most surfaces by some of the strongest attractive chemical and physical forces that exist outside of the subatomic world. For soils, including both inorganic — metal and mineral particles — and organic — oils and plant and animal products — contamination, there are several physical forces that operate. The attractive physical forces include positive and negative electrical charge interactions and other strong forces that must be explained by quantum mechanics applied to close molecular interactions. For example, the so-called “van der Waals forces.” For microbial contamination, it must be realized that the existence of microbials was unknown 125 years ago and scientists are still in the process of learning how microbials attach to surfaces. Some of the same forces that attached non-microbial particles to surfaces play roles in microbial attachment but, in addi-tion, scientists are learning that chemical attractions of types not fully understood are also present. For example, there are bacteria that can attach to a glass or plastic surface with a force so strong that if it were translated to a 1 cm2 surface area, it could support a car the size of a Volkswagen. The method that underlies the advances that have taken place in the physical and biological sciences is based on integrating past quantitative knowledge into new knowledge acquired by measured out-comes of experiments. This means that determination of the efficacy of a new cleaning process cannot depend on a qualitative measurement, such as “looking clean.” This is especially true for microbial con-tamination because all microbials are much too small to be seen by the human eye without a microscope. The basic premise of ICM is that devel-opment of an optimal cleaning process for any environment must go hand-in-hand with quantitative measurements that deter-mine how effective each cleaning step is. That is, the effectiveness of cleaning processes must be validated by experimen-tal measurements. The practical implementation of ICM, therefore, requires the availability of instru-ments capable of measuring amounts of both microbial and non-microbial contami-nation on the surfaces to be cleaned. These instrumental developments will certainly continue for the foreseeable future. The introduction of the science of ICM into the field of cleaning private, public, and corporate spaces is a logical extension of highly effective cleaning and disinfec-tion protocols developed over the past 40 years in the pharmaceutical, electronics and optical industries. These cleaning protocols have allowed manufacturers in these industries to maintain product production in rooms where contamination levels for both microbials and non-microbials are many orders of magnitude less than even the cleanest room. While the cleaning protocols that are developed using ICM are not meant to address reduction of contamination to these low levels, the same basic scientific principle is used: Any cleaning process must be validated by measurements of con-tamination levels before and after a clean-CM ing step. Plenty of work ahead Fortunately, scientific and technological developments have taken place within the last few decades that allow the quantitative measurements of contamination amounts present on surfaces before and after the application of a cleaning procedure. The instruments that allow these meas-urements to be done have grown simpler and less expensive during these decades. Circle Product Information no. 203 on page 34 www.cmmonline.com 33
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