Food water control, importance

Sulfonamides are administered to food-producing species as additives to feed and drinking water, controlled-release oral boluses, and intrauterine infusions. These drugs are applied to the brood chambers of honeybee hives mixed with confectioners sugar or in syrup. The insoluble nature of sulfonamides is an important consideration. Highly insoluble sulfonamides such as phthalylsulfathiazole are absorbed from the gastrointestinal tract very slowly and are used to treat enteric infections. With triple sulfas for oral administration, the concentration of individual sulfonamides is limited by the drug s solubility, while efficacy reflects the additive activity of all three components. Sodium salts of sulfonamides, which are readily soluble in water, are available for intravenous administration. 

The control of water activity in foods is an important tool for extending shelf life. It is responsible for the quality of foods affected by microbiological, chemical, and physical changes. The physical properties, quantity, and quality of water within the food have a strong impact on food effectiveness, quality attributes, shelf life, textural properties, and processing. 

The requirements for monitoring water quality occur in several environmental situations, in the monitoring of river quality, in the analysis and control of potable water supplies, and in sewage treatment. In addition, the quality of water is important in many industrial situations, for example, for monitoring the quality of boiler feed water, in food production, and in pharmaceutical production. Ion-selective electrodes play an important role in many of these areas. 

Quality Specifications. Because of the extreme sensitivity of polyamide synthesis to impurities ia the iagredients (eg, for molecular-weight control, dye receptivity), adipic acid is one of the purest materials produced on a large scale. In addition to food-additive and polyamide specifications, other special requirements arise from the variety of other appHcations. Table 8 summarizes the more important specifications. Typical impurities iaclude monobasic acids arising from the air oxidation step ia synthesis, and lower dibasic acids and nitrogenous materials from the nitric acid oxidation step. Trace metals, water, color, and oils round out the usual specification Hsts. 

One of the reasons why it is important to remove suspended solids in water is that the particles can act as a source of food and housing for bacteria. Not only does this make microbiological control much harder but, high bacteria levels increase the fouling of distribution lines and especially heat transfer equipment that receive processed waters (for example, in one s household hot water heater). The removal of suspended contaminants enables chemical treatments to be at their primary jobs of scale and corrosion prevention and microbial control. 

Of the numerous reasons for measuring and controlling the moisture content of dehydrated foods, one of the more important is the effect of moisture content on the stability of the food. The storage life of a food generally increases with decreasing amount of water and it is therefore customary to dehydrate the food to some safe moisture level which is determined empirically. 

Control of pH is of critical importance in many industrial operations such as water purification, food and drug preservation, and agriculture. 

Properties such as body, texture, smoothness, and chewiness in foods are related to the control of crystal structure. The most common and the most important crystalline materials encountered in foods are sugar and ice. It is necessary to control growth, or increase the size of these crystals, as in ice cream and to prevent their disappearance or solution in the solvent, which is usually water, as in icings. In most instances, characteristic crystalline structure is controlled by formulation, type and ratio of ingredients, manufacturing techniques, and proper use of equipment. 

Although the work of ATCC and others has done much to ensure the reproducibility and even demonstrate some traceability of microbiological reference materials the development of microbiological Certified Reference Materials (CRMs), certified for number of viable life forms is seen as important for control analyses of water and food. Somewhat of a holy grail the development of such CRMs has long been hampered by the unstable concentration and insufficient homogeneity of viable organisms in the materials. 

Food products can generally be considered as a mixture of many components. For example, milk, cream and cheeses are primarily a mixture of water, fat globules and macromolecules. The concentrations of the components are important parameters in the food industry for the control of production processes, quality assurance and the development of new products. NMR has been used extensively to quantify the amount of each component, and also their states [59, 60]. For example, lipid crystallization has been studied in model systems and in actual food systems [61, 62]. Callaghan et al. [63] have shown that the fat in Cheddar cheese was diffusion-restricted and was most probably associated with small droplets. Many pioneering applications of NMR and MRI in food science and processing have been reviewed in Refs. [19, 20, 59]. 

Dextran is the first microbial polysaccharide produced and utilized on an industrial scale. The potential importance of dextran as a structually (and property) controlled feedstock is clearly seen in light of the recent emphasis of molecular biologists and molecular engineers in the generation of microbes for feedstock production. Dextran is employed as pharmaceuticals (additives and coatings of medications), within cosmetics, as food extenders, as water-loss inhibitors in oilwell drilling muds and as the basis for a number of synthetic resins. 

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