[FOOD SAFETY & QUALITY] by Neil H. Mermelstein Viewing Salt with a Grain of Salt he phrase “take it with a grain through rock salt mining, 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 Morton Salt 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 foods, 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 sea salt 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 Kosher salt 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 Cargill 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 sodium chloride made from vacuum-crystallized cubes increases adherence to sur- include tests for sodium and chlo- salt include table and cooking salts 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 09.14 • www.ift.org 73 pg [FOOD SAFETY & QUALITY] 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.