[ SAFETY & QUALITY]

by Neil H. Mermelstein

Viewing with a

he phrase “take it with a grain through rock , in which the company Joy Morton & Co. After of salt” means to look at some- large chunks of salt are crushed several more acquisitions, the com- Tthing skeptically. Accordingly, and brought to the surface for sub- pany was renamed the suppliers of salt and food compa- sequent processing into different Co. in 1910. The company started nies using salt as an ingredient take crystal sizes by screening, or through adding an anti-caking agent to salt in a close look at the salt they produce solution mining, in which water is 1911, creating a table salt that flowed or use, essentially looking skepti- pumped into a salt deposit to dis- freely, even in humid weather, and cally at the salt until it is proven to solve the salt and the resulting brine started using the iconic Umbrella have the quality intended or desired. is pumped to the surface for subse- Girl logo and slogan When It Rains It Salt is an important ingredient quent mechanical heating in open Pours® on the company’s table salt in many , serving as not only a or closed (vacuum-pan) evapora- package and advertisements in 1914. flavor enhancer but also a preserva- tors. Additives used in salt include Today, the company produces tive and functional ingredient. It is anti-caking agents and nutritional more than 50 grades and mix- generally cubic in structure but can compounds such as potassium tures of salt. Eric Shirk, Director of be modified into additional shapes iodide used to make iodized salt. Quality, described three types of with different characteristics use- salt the company markets, based ful for specific food applications. Morton Salt on production method. Rock salt The two primary sources of Morton Salt Inc. (www.mortonsalt. is mechanically removed from an salt are seawater and underground com) began in 1848 when Alonzo underground salt deposit by rock salt salt deposits. Salt from seawater Richmond created Richmond & mining and ground and screened to is obtained through the effects of Co., Agents for Onondaga Salt. Joy various particle sizes. The result- sun and wind (solar heating), and Morton acquired a major interest in ing crystals are fractured cubes that salt from salt deposits is obtained the company in 1889 and renamed have smooth surfaces and tend to be orthorhombic in shape (having Salt from seawater is obtained through evaporation as in this salt pond. © domonite/iStock/Thinkstock 90º angles); these are the hardest of the salt particles. The only food- grade salt that Morton Salt produces by this process is Rock Pretzel Salt. Solar salt uses brine from vari- ous sources, including seawater, saline lake water, and brine pro- duced by dissolution of a salt deposit. The brine is evaporated in ponds using solar energy until the salt crystallizes. The crystals are then washed and screened to vari- ous particle sizes or compacted into larger particles, pellets, or blocks. Food-grade in fine, medium, and coarse versions is produced using this process. The crystals are hopper-shaped aggre- gates of cubes with the center filled in, resulting in relatively hard parti- cles. Solar salt that has been ground pg 72 09.14 • www.ift.org consists of multi-shaped particles. The finest screen grade can be used Dendritic (star- Morton Salt’s sea salt is harvested for topical applications such as oil- shaped) crystals directly from seawater off the roasted nuts and small crackers. provide extended surface area. Photo coast of California and is marketed Granulated salt may also be com- courtesy of Morton Salt under the following product names: pacted into larger particle sizes. Inc. Refined Sea Salt, TFC Refined Sea is produced from the Salt, and California Pure Sea Salt. coarse grade of this product by Vacuum-crystallized salt uses a compacting evaporated salt into saturated brine solution, acquired thin flakes that adhere well to a by either solution mining of a salt food product. In addition, granu- deposit or dissolution of salt from lated salt can be ground and milled either a solar process or rock mine. to produce very fine pulverized The brine is treated before using it in grades for use in microwave pop- the vacuum pan process to remove corn and butter where they can be calcium and magnesium impuri- carried by an oil or brine slurry into ties that are usually present in small the food process. Coarse grades Granulated salt, the amounts from salt deposits, Shirk are also produced to meet other form most said. It is then concentrated in a food processing requirements. commonly used, is series of steam-heated, multiple- Morton Salt also produces a generally cubic in shape. Photo courtesy effect vacuum pans until the salt unique dendritic (star-shaped) of crystallizes. The crystals are either crystal for the food industry called used as they are, sorted by screen- Star Flake ®. The porous modified ing into various particle sizes, ground cubes have a lower bulk density to fine particle sizes, or compacted and greater surface area than regu- into larger particles, pellets, bricks, lar vacuum-pan salt and a slightly and blocks. The resulting high-purity smaller average particle size. salt is used in both the food indus- This salt is used in food applica- try and the pharmaceutical industry. tions such as snacks for which Food-grade consumer products the extended surface area of the specifications for made from vacuum-crystallized cubes increases adherence to sur- include tests for sodium and chlo- salt include table and cooking faces. The product is also used in ride identity, sodium chloride assay, (iodized and plain) and kosher salt. seasonings and baking mixes. arsenic, and heavy metals. Like The most common salt for Shirk said that quality control others in the salt industry, Morton industrial use is generally called tests are conducted to ensure that Salt uses the American Society for granulated salt and is made from sat- the company’s products meet the Testing and Materials (ASTM) E534 urated brine and produced without standards published by the U.S. method to analyze for the principal further treatment, Shirk said. This Pharmacopeial Convention (USP) in salt impurities and subtracts these salt is relatively pure (at least 99.7%) its Food Chemicals Codex (FCC), a values from 100 to determine the per- and can be screened to produce compendium of internationally rec- cent sodium chloride, Shirk added. two categories of salt in addition to ognized standards for purity and To analyze for other impurities the unscreened grade: table grade, identity of food ingredients. Salt that are either not normally pres- marketed under the Morton ® brand, meeting USP standards exceeds the ent or present in minute amounts, and a very fine screened grade. All U.S. Food and Drug Administration’s the company uses methods from products in this category are cubic good manufacturing practices. All the FCC, the USP, Standard Methods crystals that have a uniform par- salt products are tested for purity, for the Examination of Water and ticle size. Table grades include the and while purity levels vary by salt Wastewater, and adaptations vali- salt used in most salt shakers and type, the purity of each process loca- dated by Morton Salt specifically salt for the food processing market. tion tends to be fairly consistent. FCC for use on salt and brines. For

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Viewing Salt with a Grain of Salt continued...

that only Cargill is allowed to bring in from San Francisco Bay to ponds where wind and sun evaporate it naturally. The resulting crystals are further processed to ensure food-grade quality, using standard industry processing techniques including screening, sorting, crush- ing, washing, or dissolution followed by mechanical evaporation. Sea salts tend to be less uniform in shape than salts produced by other processes. Hollow microspheres of Granulated salts sold under the Soda-Lo® salt maximize Diamond Crystal and Cargill ® brands surface area relative to volume, providing a are made through a closed evapora- clean salt taste with tion process. Water is injected into lower levels of sodium. underground salt deposits to cre- Photo courtesy of Tate & Lyle ate a brine. The brine is pumped up to a closed vacuum-pan evap- orator on the surface where the water is evaporated by heat pro- example, salts for pharmaceutical such as a high concentration of dis- cessing. The resulting crystals products are tested using mono- solved salts can either suppress are sized by screening and may graph methods specified by the or enhance the analyte signal. have various additives added to USP, including colorimetry, titration, improve their ease of handling or gravimetric analysis, atomic absorp- Cargill provide nutritional supplement. tion spectroscopy, fluorometry, In 1886 John and Louis Alberger, The Alberger brand salt is pro- flame tests, turbidity, and others. Charles Moore, and Horace Williams duced in an open-pan evaporation Particle size analysis is measured patented a new process for mak- process, which produces salt more primarily using mechanical sieve ing salt and founded the Diamond slowly than the closed process, shakers and is based on the ASTM Crystal Salt Co. This Alberger ® salt allowing different shapes of salt C136 method. Bulk density testing process made it possible to cre- crystals such as hollow pyramids is based on filling a container with ate unique-shaped crystals with and cubic agglomerates to form. a known volume and weighing the numerous facets that exhibited The shape of the crystals provides contents on a balance. Anti-caking extraordinary adherence, blend- unique characteristics. The crys- agents are analyzed by titration, ability, and flavor.The Diamond tals are sized by screening and may colorimetry, turbidimetry, or gravi- Crystal ® brand was acquired by have various additives added. metric methods. Iodine is analyzed General Foods in 1929, Akzo Nobel Van Norden said that granulated by titration with sodium thiosulfate. in 1987, and Cargill (www.car- salts are generally cubic in shape Shirk said that the technology gill.com), the largest marketer of and that the manufacturing pro- for evaporating brine in vacuum- salt in the United States, in 1997. cesses affect the size and shape of pan crystallizers has been used Jackie Van Norden, Product the salt crystals. Salts made by the for approximately 100 years. Line Manager at Cargill, said that are flakes that have Computerization using pressure, the company offers kosher salt, sea high surface area and low bulk den- temperature, and flow sensors is salt, , and table salt for sity with the largest crystals shaped an advancement that enables vir- consumer use under the Diamond like hollow pyramids and the smaller tual processing control systems. Crystal brand and salts for food flakes shaped like cubed agglomer- Analytical advances include use of industry use under various brands, ates. Premier salts and FlakeSelect inductively coupled plasma (ICP) including Alberger ®, Premier™, salts are granulated salts that have spectroscopy to replace some of the FlakeSelect™, and Microsized ® as been compacted into flat flakes that manual procedures, but analyzing for well as granulated and sea salts. It have higher surface area and lower sodium by both ICP spectroscopy and also offers table salt for consumer bulk density than granulated salt and flame atomic absorption (FAA) spec- use under the Sterling ® brand. provide better adherence for topi- troscopy can be challenging since Cargill uses several processes to cal applications. Alberger, Premier, it is crucial to prevent interferences produce its salts. Sea salt is made by and FlakeSelect salts range in size due to the matrix. Difficult matrices channeling Pacific Ocean seawater from a very fine flour salt to a very pg 74 09.14 • www.ift.org coarse topping salt. Microsized its salts, both plain and iodized, for Tate and Lyle (www.tateandlyle. salts are granulated salts that consumer use under the Carey Salt com) signed an exclusive agree- are mechanically pulverized and brand in the United States, the Sifto ment with Eminate Ltd., a subsidiary screened to a very fine particle size. Salt brand in Canada, and a num- of the University of Nottingham, Providing a variety of salt sizes and ber of private labels. Its industrial in October 2011 to license and dis- shapes allows food manufactur- food-grade salts (available in gran- tribute Eminate’s Soda-Lo ® Salt ers and foodservice operators to ulated, blending, iodized, and flour Microspheres worldwide. The optimize their salt and sodium con- salt forms) are sold under the Special salt was introduced in Europe and tents in specific food applications. Purity brand in the United States and North America in November 2012 Sarah Hubert, Quality Assurance the HyGrade brand in Canada. For and subsequently in Latin America Leader, and Roger Sonnier, Regional food use, the company offers only and Asia Pacific and received the Quality Assurance Manager, said cubic crystals and sea salt crystals. Institute of Food Technologists’ that Cargill tests its salts for purity, moisture, insolubles, screen size, The most common salt for industrial use is generally called granulated salt additives (if applicable), and bulk and is made from saturated brine and produced without further treatment. density, using wet chemistry equip- ment, spectrophotometers, pH Compass Minerals offers 2013 Food Expo Innovation Award. meters, sieves, and atomic absorp- granulated salt, kosher salt, sea Sue Butler, Senior Research tion spectrophotometry. To test for salt, and canning and salt. Scientist at Tate & Lyle, said that purity, the company uses acid/base Sodium ferrocyanide, also known the product is made by a proprietary titration with EDTA to determine the as yellow prussiate of soda (YPS), spray-drying technology that calcium and magnesium concen- is added as a free-flowing/anti- turns standard salt crystals into trations. Sulfate determination is a caking agent that generally doubles free-flowing, hollow crystalline gravimetric procedure (dissolution the shelf life of salt, depending on microspheres. The lower- of salt in water addition of barium storage conditions, Poe said. Salt density microspheres optimize chloride, subsequent filtering, dry- is chemically stable infinitely but the perception of saltiness in ing, and weighing of the precipitate). cakes into lumps over time, and foods by maximizing surface To determine bulk density, the YPS delays the lumping. Poe said area relative to volume, making company places a salt sample in a that the company monitors the YPS it possible to provide a clean salt container of known volume. To test content of the salt colorimetrically. taste with lower levels of sodium. the anti-caking agent, a spectro- YPS is converted into blue ferric Every lot of the microspheres photometer is employed to measure ferrocyanide in the presence of iron is quality tested to ensure that it is the color created via a chemical in an acidic medium, and the color free of microorganisms and meets reaction between an anti-caking intensity can be measured against a specifications for moisture and ash, agent and a laboratory reagent. known standard. The darker the blue Butler said. Particle shape and size For free-flow agents, an acid-base color, the higher the YPS content in are also measured. Some of the titration with a known concentra- the salt. In addition, the company methods used include the forced-air tion of aqueous sodium hydroxide uses sodium silico aluminate as oven method for moisture measure- is used. For particle size analysis, a a desiccant in its consumer salt ment and the laser light-scattering sample of known weight is poured to attract moisture away from method for particle size analysis. into the top sieve of a series of the salt and keep it flowing. In the forced-air oven method, a sized wire-mesh sieves, the sieves Poe said that Compass Minerals sample is heated under controlled are mechanically shaken, and the typically analyzes salt for purity conditions to drive off all free mois- individual sieves are weighed. by x-ray diffraction and ICP spec- ture and the reduction in weight is trophotometry. Insoluble matter used to calculate the percentage of Compass Minerals is determined gravimetrically by moisture lost. The laser light-scat- The former North American Salt ASTM Procedure E534, and par- tering method measures the amount Co. is in the process of changing its ticle size analysis is done with of light scattered by a solution at name to Compass Minerals (www. screens. Samples are sent to an angle relative to a laser beam, compassminerals.com). The com- outside laboratories to deter- which enables particle measure- pany traces its history as far back as mine content of heavy metals. ment in the sub-micrometer range. FT 1844. Jerry Poe, Director of Quality, said that the company’s salt produc- Tate & Lyle Neil H. Mermelstein, a Fellow of tion methods include mechanical Through its Open Innovation program IFT, is Editor Emeritus of evaporation, solar evaporation, and that creates outside partnerships Food Technology rock salt mining. The company offers to bring new innovations to market, • [email protected]

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