Food industry table salt production

USP-grade anhydrous magnesium carbonate is used as a flavor impression intensification vehicle in the processed food industry (see Flavors and spices). Basic magnesium carbonates are used as free flowing agents in the manufacture of table salt, as a hulking agent in powder and tablet pharmaceutical formulations, as an antacid, and in a variety of personal care products (see Pharmaceuticals). 

Table 6.1 summarizes the uses of salt. Nearly half is consumed in the important electrolysis of brine to form two top 50 chemicals, sodium hydroxide and chlorine. One fourth is used on highways for deicing and competes with calcium chloride in this application. The food industry and animal feeds make up other important uses. Salt is surpassed only by phosphate rock in total production of all minerals. Its annual production is nearly 90 billion lb. 

Sodium is the most abundant metal in sea water. Sodium chloride is commercially produced from sea water by solar evaporation. Salt is a dietary necessity, but only a small fraction of the production is actually used as table salt in foods. The chemical usages for sodium are so extensive that salt is one of the most important raw materials for the chemical industries. 

It is sometimes the practice in the food industry to add the most bioavallable iron salt at the last practical processing step, with the hope of maintaining iron bloavallability with no sacrifice in product quality. For example, ferrous sulfate is sometimes used at the bakery level for enriching flour during dough formulation. It is not added to the flour at the mill because ferrous sulfate is a prooxidant and can cause rancidity and off flavors (7). The less reactive and more flour compatible iron phosphates are sometimes avoided, based upon research which show the iron phosphates are not bioavallable. The preference for one iron source over another stems from their relative ranking in terms of biological values, as shown in Table II. 

The electrodialytic processes have experienced a steady growth since they made their appearance as industrial scale separation processes about 20 years ago. Currently the desalination of brackish water, the chlorine-alkaline electrolysis and the production of table salt are still the dominant applications, but new areas of application in the food and chemical process industry and the use of hybrid processes are gaining interest rapidly. 

Iodi2ed salt is the most important source of iodine worldwide, and is also the agreed strategy for achieving iodine sufficiency (WHO/UNICEF/ICCIDD, 2001). Although Norway has never had mandatory iodization of salt, some brands of table salt are fortified with iodine, and regulations permit the addition of 5 pg of iodine per gram of NaCl (Ministry of Health, 2002). Industrial salt used in food production is not supplemented with iodine (Frey, 1986). 

The nationwide survey of iodine status in reunified Germany (Manz et ai, 2002) found an inadequate iodine intake, also among 50-70-year-old subjects, despite an increase in iodine intake for the last 20 years (Table 116.4). In Germany, the use of iodized salt in households and the food industry is voluntary, and since 1990 there has been a considerable increase in the production of iodized salt (Manz et ai, 2002). 

Electrodialysis 1. Desalination of brackish water 2. Production of table salt 3. Waste water treatment 4. Concentration of RO brines 5. Applications in the chemical, food, and drug industries... 

Hydrogen cyanide (HCN) is a colorless, highly poisonous gas or liquid (below 26.7 °C) having an odor of bitter almonds (Hartung 1994 Pesce 1994). It is a weak acid. Exposures may occur in industrial situations as well as from cigarette smoke and combustion products and from naturally occurring cyanide compounds in foods. There is a potential for exposure when any acid is mixed with a cyanide salt. Intravenously administered sodium nitroprusside (Na2[Fe(CN)5N0]-2H20) has been used clinically to lower blood pressure (Schulz et al. 1982). Chemical and physical properties are listed in Table 5-2. 

Sodium chloride, or common salt, is one of the earliest chemical commodities produced. Its production from seawater was prompted by essential dietary needs, and later for its value as a food preservative caused by the scattered accessibility of land-based sources. The word salary itself is derived from the Roman salarium, which was a monetary payment given to soldiers for salt purchase to replace the original salt issue. While the initial production and harvesting of sodium chloride was from dietary interests, food needs today represent less than 3% of consumption, and uses as a chemical intermediate far exceed this (Table 6.1). The wide availability of sodium chloride has contributed to the derivation of nearly all compounds containing sodium or chlorine from this salt, and to the establishment of many large industrial chemical operations adjacent to major salt deposits. Three general methods are in common use for the recovery of sodium chloride, which in combination were employed for the worldwide production of 225 million tonnes of this commodity in 2000 and 183 million tonnes in 1990 (Table 6.2). 

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