Miller Magazine Issue 110 / February 2019

55 COVER STORY MILLER / FEBRUARY 2019 boratory and a strict quality control plan are key to the succes- sful implementation of Lean Six Sigma in any company. QUALITY OF WHOLE GRAINS The most impor- tant parameters to control are: Moisture: Most grains need to be stored at less than 14% moisture. Hi- gher moisture pro- motes the growth of insects and mold. Foreign matter: It is the dust, hul- ls, sticks, and any other thing that is not a grain or just shouldn’t be there. For example, a grain of sorghum is considered foreign matter if you are analyzing a batch of corn. Specific weight: How many tons of grain are contai- ned in a cubic meter. In agriculture, an equivalent dimen- sion called hectolitre weight is used, and it is measured in kilograms per liter. Fat content: In the case of soybeans and sunflower, fat content is the main parameter of interest for oil pro- duction. It is especially important for animal feed too. Oil mills would use solvent extraction methods to test it, but feed millers and other people just need a NIR analyzer. Presence of insects or mold: A visual inspection al- lows to find the bites of insects in the grains. If you find grain dust, “spider webs” (actually silk of the larvae) and little holes in the grain, you have insects. Mold has a distinctive odor. Physical damage: It may be because of water, fire, freeze, crushing. Basically, the grain doesn’t look as it should. Too dark, too white, etc. Toxins: When a fungi attacks the grain, either in the field or in the grain bin, it produces mycotoxins. As with every other substance in the world, there are safe and unsafe levels. A quick test may be performed using a bla- ck light, just to know if there is or has been mold there. For precise detection of specific toxins and controlling the levels, you should use an ELISA test. There are seve- ral types available for the different toxins. Color: Having a batch of grain with an unusually pale color may indicate that the grains were treated with pes- ticide for use as seeds, and someone later changed his mind. Seeds are tinted to make them look different and avoid confusion with edible grains, but people of dubious ethics may wash them with bleach after a seed contract gets busted, as it is easier to sell edible grains. QUALITY OF MILLED GRAINS The parameters to be controlled depend on what you would do. Corn may be dry or wet milled, and the para- meters would be different despite being the same grain and (almost) the same end products. Same goes for sor- ghum. Rice and wheat are dry milled. Oat is peeled and crushed. Soybean and sunflower are crushed and sort of wet milled (with hexane instead of water). In most cases, you need all the things you used for whole grains, plus some other. Hand Mill: Again, depends on the grain and the pro- cess. There are even lab scales mills for wet milling. Most of the time, you need a grinder that will turn the grain into a rough flour, in order to use solvent based tests. Moisture: The acceptable moisture for milled grains is much less than for whole grains, because there is no longer any breathing to cool the product. In general, to avoid infestation, you need less than 8% moisture. Particle size: Animal feed depends strongly on par- ticle size. The same goes for many human-consumption