Growth of micro-organisms

For jet fuels, the elimination of free water using filters and coalescers by purging during storage, and the limit of 5 ppm dissolved water are sufficient to avoid incidents potentially attributable to water contamination formation of micro-crystals of ice at low temperature, increased risk of corrosion, growth of micro-organisms. 

The growth of micro-organisms used in the production of amino adds is done in a well balanced environment. The conditions required are ... 

The uncontrolled growth of micro-organisms in metalworking fluids can result in a wide range of problems. These can include ... 

The temperature of the cooled water can at best approach the wet-bulb temperature of the air. Practically, the engineer usually designs on the basis that the water will be 8-13°F (4.5-7°C) above the wet-bulb temperature.12 Since this is an open system, and oxygen is picked up with each pass through the system, corrosion and the growth of micro-organisms within the system are facilitated. For this reason, pretreatment of the water is necessaiy. 

Figure 7.17 Stability map for non-fat milk solids showing schematic rates of various deteriorative changes and growth of micro-organisms as a function of water activity (from Roos,...

Fermentation of lactose during the growth of micro-organisms in milk has a major effect on its redox potential. The decrease in the h of milk caused by the growth of lactic acid bacteria is shown in Figure 11.3. A rapid decrease in h occurs after the available 02 has been consumed by the bacteria. Therefore, the redox potential of cheese and fermented milk products is negative. Reduction of redox indicators (e.g. resazurin or... 

The continuous growth of micro-organisms, as with continuous chemical reactions, may be carried out either in tubular fermenters (plug flow) or in well-mixed... 

As mentioned earlier, carbon dioxide, though not added specifically as a preservative, contributes to the inhibition of the growth of micro-organisms and, coupled with other factors (e.g. pH), contributes to the stability of a drink. 

The choice of process depends on the level of microbiological contamination of the raw materials and packaging, and the ability of the product to withstand growth of micro-organisms (e.g. preservative levels and sugar content). Also of great importance is the ability of the product to withstand heat. 

These methods are highly sensitive to interferences that limit the growth of the micro-organism and often take rather a long time to perform, as they rely on the growth of micro-organisms under stressed conditions, for example, limited levels of a critical vitamin. However, they do generally offer quite specific methods. Very special skills are required to run these tests effectively. 

Provide smooth, easily cleanable surfaces on equipment, floors, walls, and ceilings to minimize the opportunity for collection of particulates and growth of micro-organisms... 

One of the first cases of the application of membrane bioreactors in food processes was the production of milk with low lactose content. (3-galactosidase was entrapped into cellulose acetate fibers to carry out the hydrolysis of milk and whey lactose [2] recently the system was improved by the use of microfiltration and by UV irradiation of the enzyme solution to avoid growth of micro-organisms [45]. 

Film-forming finishes such as paints, lacquers, and varnishes have long been used to protect wood surfaces. The film-forming finishes are not preservatives they will not prevent decay if conditions are favorable for growth of micro-organisms. 

S Biological corrosion. Damp masonry surfaces allow the growth of micro-organisms such as bacteria, moulds, mosses, algae and lichens (Figure 6.11). With an efficient metabolism the separation of the products of metabolism can result in the deposition of salts. If walls are not treated the effect is an uninhabitable building. 

The ability of a yeast to utilize a compound as the sole source of carbon for growth may be tested in a chemically defined medium that lacks any organic compound, except perhaps for certain vitamins. The organic compound to be tested may be added to the medium at a concentration of, for example, 50 mM. Practical aspects of studying the aerobic growth of micro-organisms are summarized in Ref. 130. 

Microbial fermentations must be tightly controlled to ensure optimal growth of micro-organisms and efficient production of enzymes. As shown in Fig. 4, a modern fermentor will allow operators to control the temperature, pH, redox potential, and dissolved... 

---