Microorganisms surface composition

The data accumulated for a large variety of microorganisms are very disperse regarding the relationship between electrical properties and surface composition. Better correlations are obtained when the comparisons are restricted to limited sets, particularly to taxonomically related cells. The NjP concentration ratio was directly correlated with the isoelectric point (iep) for a collection of brewing yeasts and inversely correlated with the electrophoretic mobility measured at pH 4 for a collection of strains including different yeasts and bacteria. ... 

Biological Corrosion The metabohc activity of microorganisms can either directly or indirectly cause deterioration of a metal by corrosion processes. Such activity can (1) produce a corrosive environment, (2) create electrolytic-concentration cells on the metal surface, (3) alter the resistance of surface films, (4) have an influence on the rate of anodic or cathodic reaction, and (5) alter the environment composition. 

It is now known that teeth undergo a continuous process of demineralisation and remineralisation (see Table 2), which is driven by changes in the plaque composition [29]. In the presence of fermentable carbohydrates plaque microorganisms generate characteristic organic acids, that is, lactic and acetic [17], and these diffuse through the pellicle to the tooth surface and cause demineralisation [30]. Ions are then liberated from the mineral phase into this low pH liquid [31], and they diffuse outwards and re-precipitate at the surface layer of the demineralised lesion [32,33]. If this process is sufficiently rapid, there is a net loss of tooth mineral and irreversible cavity formation. 

The film that forms on the surface is very complex physically and microbiolog-ically, but it is useful to conceptualize the film as a simple model (see Figure 5.3). The cells are embedded in this hydrogel coating. The substratum (left) will be defined later. For now we will consider it inert and nonabsorptive. The biofilm layer is a complex composite of the microorganism and a hydrogel vehicle. The phase immediately in contact with the biofilm is called the boundary layer. 

Container Cleanliness of Marketing Product The previous cleanliness of containers filled with the product will depend on their transportation exposure, composition, and storage conditions. Glass containers usually carry at least mold spores of different microorganisms, especially if they are transported in cardboard boxes. Other containers and closures made with aluminum, Teflon, metal, or plastic usually have smooth surfaces and are free from microbial contamination but may contain fibers or insects [45], Some manufacturers receive containers individually wrapped to reduce contamination risks and others use compressed air to clean them. However, the cleanliness of wrapped containers will depend on the provider s guarantee of the manufacturing process and compressed-air equipment may release vapors or oils that have to be tested and validated [6],... 

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