Material surfaces in clean room and sterile technology

VDMA 2005
PDF
154 pages

ISBN 3-8163-0506-7

An official statistic from 1998 shows the additional costs incurred by the food industry in the United States of America of more than 30 billion due to recalls, compensation payments and loss of sales following food infections. Around a quarter of these costs can be attributed to a lack of hygiene and cleaning of facilities. The number of unrecorded cases is estimated to be of the same order of magnitude. Undesirable residues on the material surfaces of industrial plants, such as solid particles or microorganisms, lead to the problems mentioned above and the associated costs. No comparable statistics are currently available for Europe. However, the total costs of avoidable damage due to inadequate cleaning will be similar. Increased quality awareness on the part of the consumer means that greater demands must be placed on cleaning after production breaks and when changing products in order to avoid contamination by residues. This requirement is supported by the increasing allergological sensitivity of the population, for example in the production of foods containing nuts. In general, products in the food, biotechnology and pharmaceutical sectors should have a high product quality and product safety.
In addition to the appropriate selection of raw materials and processing methods, this can be achieved by optimizing plant cleanability (hygienic design) and cleaning components and surfaces that come into contact with the product. The reduction of dirt and pollutant particles is the basis for achieving the desired goals. It would therefore be desirable to prevent the accumulation of individual cells or particles in order to avoid microbiological contamination. This means that the formation of biofilms and dirt deposits is suppressed by suitable means at the moment of initial particle contact. A plant constructor or operator must assess when an inspection, sterilization or removal of components should be carried out. For an engineer, calculating the stress distribution in a container or the heat transfer in a heat exchanger is part of everyday life, but it is not possible to predict the contamination of a pharmaceutical plant during the design phase. In order to avoid damage caused by contamination and product contamination, the plant manufacturer must be able to estimate the surface quality at which contamination of the plant is to be expected. This has an effect on the process safety of the plant operator on the one hand and on the production costs of the plant manufacturer on the other. This problem cannot be solved by simply stating that the surface should be as smooth and shiny as possible. Biofilm formation as a causal reaction, the surface as an effect parameter and the cleanability of a component as a result can only be insufficiently characterized with the test methods and approaches of classical mechanical engineering. According to both the hygiene guidelines (HACCP concept) and the Machinery Directive, the European Commission expects all manufacturers to provide proof of the use of sufficient surface qualities for components and equipment without defining the term "sufficient quality".
The technical cleaning evaluation of material surfaces is therefore a necessity for companies whose products are used in sterile, cleaning and cleanroom areas. The basis of the recent findings from research projects summarized in this book is the scientific and technical question. How should a surface be structurally designed to prevent the adhesion of components? The application-oriented design and optimization with regard to cleanability (minimum effort, effective, environmentally friendly) play a decisive role here. However, statements on cleanability can only be made if material parameters are developed that also include interfacial reactions. It is clear that only interdisciplinary research can lead to success. By combining the results of two research groups of the AIF group Materials Surface, Adhesion, Cleaning with the partners BAM Berlin, MAK TU Munich and FH Jena, the DFG group Microbial Interaction with Material Surfaces with the institutions MLU Halle, TU Dresden, HKI Jena and FH Jena, this book provides a technical overview of biofilm formation and its microbiological and materials science characterization, as well as the effect on adhesion and cleanability. Parameters are defined which make it possible to describe the surface-to-cleanability ratio more precisely than before. Last but not least, we see this book as a guide for engineers working in practice who have to deal with these problems in the fields of pharmaceutical, biotechnology, food and cleanroom technology.