Guarding Grain Quality
Providing feed manufacturers, exporters and end users with quality grain requires the use of best management practices, measurement tools, the right equipment and a healthy body of knowledge. Proper bin management strategies, such as aeration, moisture management and pest control are equally important as performing the right diagnostics and utilizing the best drying methods for each individual situation.
Guarding Grain Quality
provided by:
Guarding grain quality is the mission of thousands of grain elevators and farms across America. The guardians of grain quality dedicate their lives to monitoring the commodity at every step in its lifecycle from harvest to feed trough, and it's not always an easy job. Providing feed manufacturers, exporters and end users with quality grain requires the use of best management practices, measurement tools, the right equipment and a healthy body of knowledge. Proper bin management strategies, such as aeration, moisture management and pest control are equally important as performing the right diagnostics and utilizing the best drying methods for each individual situation.
The reality is there's nothing anyone can do to make grain better after it's been harvested. "Grain quality may be maintained but will not be improved," Scott Chant, president of Safe-Grain, reminds us. "The quality of the incoming product is as good as it will ever be. The operator can clean, dry, fumigate, transfer and segregate incoming product, but again, the incoming quality is as good as it will ever be," he explains. Using time-tested techniques and equipment helps ensure the quality of your commodity doesn't decline at any point along the way to its final destination.
Grain drying and moisture management
After grain is harvested, the next step is drying. Moisture management plays a huge role in grain drying, according to Randy Coffee, director of marketing at Sukup Mfg. Co. Measuring the moisture content of the grain before drying is a crucial part of maintaining high quality. This is achieved through the use of moisture monitors and temperature sensors. "We typically monitor the grain kernel as it comes over the sensor and read the temperature and moisture levels at once," says Coffee.
After the starting moisture level is determined, one can calculate the drying time and temperature. Grain that is high in moisture may require higher heating temperatures and longer drying times. Conversely, low moisture kernels do not need as long a drying time and may achieve the appropriate moisture level at lower temperatures.
The next goal is to make sure moisture does not migrate during storage, causing mold or fungus to grow and spread. The easiest way to prevent moisture from occurring is to completely cool the grain to an ambient temperature in the dryer, or cooling the grain in the storage bin after leaving the dryer. Portable dryers are capable of fulfilling several different drying needs. They can dry and cool the grain within the dryer or use full heat to dry the commodity, which then requires the grain to cool in a storage bin.
When grain first comes out of the dryer in full heat mode, it's about 130 F and 17% corrected moisture. Cooling the grain utilizing a ½-cfm airflow in the storage bin should achieve a final moisture of 15%. Once it cools to ambient temperature, it's ready to be stored until it's sold or used.
Storage considerations
Mills and elevators know that it is not enough to simply house the commodity; they must ensure the product doesn't lose any quality while waiting to be used or shipped. Whether long term (three months or longer) or short term (anything less than three months), grain must be properly stored to prevent spoilage from occurring. Temporary storage is commonly resorted to when bin space is limited and other large vacant areas are available nearby the harvest location. However, Ed Benson, general sales manager at Chief Agri-Industries, warns that temporary storage may, in some instances, promote spoilage.
According to Benson protecting the commodity should be a higher priority than creating a quick-fix storage solution. "Recently we're seeing more people store grain in a bin rather than using temporary storage spaces so they can monitor it better year-round," Benson says. "Long-term storage is advantageous because we're dealing with $5/bushel for certain grains, so it's more important to protect it now than it has been in the past," he adds.
Chant recommends regular cleaning of grain storage bins to ensure the grain remains in the best possible condition. "You shouldn't go more than three years without completely emptying and cleaning the bins. We've seen elevators hold grain for up to five years and suffer serious consequences," he says.
But using a properly cleaned storage vessel is only a part of keeping grain high quality. Using effective aeration techniques elongates the time grain can be stored before spoilage occurs.
Bin aeration
Keeping dry and even wet grain for a long period of time is relatively easy, if correctly aerating the product. Aeration aids in maintaining a consistent relationship between the grain temperature and the outside air temperature. Maintaining this equilibrium will minimize moisture migration and deterioration rates. An aeration system allows the operator to bring the grain to the desired temperature using either outside or ambient air.
Although finding the perfect grain temperature for the job can be exacted to a science, a general rule of thumb is the cooler the grain, the better. Bill Sturtz of Boone Aeration outlines the advantages of keeping grain at a low temperature. "Cool grain is not subject to damage by insect and mold activity. Those quality barriers become more active once the commodity hits 85 F. Ideally, the grain should be kept above freezing, but as cool as possible," says Sturtz.
Chant says the target temperature guidelines for corn and beans is below 48 F and wheat is below 56 F.
Factors like seasons, type of grain, duration of time storing and geographical location all determine how to achieve the prescribed temperature. "Twenty-five percent moisture corn arriving at an elevator in Georgia in August poses different issues than 25% moisture corn arriving at an elevator in Minnesota in November," Chant says. "The corn arriving in Georgia will undoubtedly require the use of fans to safely hold the corn prior to grain drying and long-term storage."
However, cooling is easier in some regions because of the climate. For example, "typically in the Upper Midwest the crop is harvested in the fall and the temperature must be brought down, which is done naturally at that time of year as the outside temperature declines to 35 or 40 F," Sturtz says.
Long-term storage that crosses seasonal boundaries requires extensive planning. Charts, such as the one Chant uses (on pg. 26), can help grain storage facilities determine how long they may safely store corn at various temperatures and moisture contents.
Avoiding unstable grain conditions is the prime objective of a successful aeration system. Grain stored above 75 F and 30% moisture content is extremely unstable, and will spoil rapidly.
Benson warns that effective management is half the battle in ensuring an aeration system will do its job. "You can design the best products and possess all the knowledge in the world, but without diligent management, it won't make a difference," Benson says.
An automatic aeration program, which uses fans that are programmed to keep the grain at a certain temperature, can be an effective way of managing bin aeration. "Recent dramatic increases in commodity pricing has made the customer more willing to spend money on a better aeration system because the cost of the update is more than offset by the added protection from better aeration," Chant says.
Pest control
After taking all the proper measures to ensure proper grain drying, storage and aeration, the last thing an elevator wants to encounter is a pest control problem. It's nearly impossible to altogether eliminate the presence of insects since they easily enter the bin through natural building openings, shipments and ventilation ports, but it's in the elevator's best interest to try and minimize the situation.
Pests can degrade grain quality by damaging kernels, introducing moisture, contamination and causing bad odors. Proper aeration will, of course, help prevent pests from getting out of hand, but in case one should find themselves with an insect, rodent or bird problem, pest control methods are available to address the unwanted invaders.
Jerry Heath, product manager and staff entomologist at Industrial Fumigant Company, explains how closely intertwined proper aeration is with pest control. "Insects thrive in moisture and heat, so cooling grain through aeration is one of the first steps in avoiding a problem. Keeping the grain cool doesn't kill any insects but holds the population at a status quo rather than continuing their growth," Heath says. Chant agrees and attests that insects begin to cause problems in environments above 56 F.
Industrial Fumigant Company uses a pyramid model (on pg. 28) to demonstrate the steps in properly addressing a pest control problem. First, understanding your pest threats will aid in preventing problems. "Identify your pests and understand their biology. You can attack them at a vulnerable stage if you know their life cycle or specific needs, or you can minimize attractant factors," Heath says. Some common pests include the lesser grain borer, maize and rice weevils, Indian meal moth and a number of others.
Next, a sanitation program should be designed to keep the most critical areas clean, deny harborage and disrupt the pest's life cycle. A good sanitation program begins with clean bins. Heath finds that damaged kernels and foreign material tends to concentrate in a central column or core. Some bin designs make it easy to unload these bad cores, leaving behind the best quality grain.
Diligent inspection and monitoring are additional tactics. Heath comments that a simple, overlooked tool can be an inspector's best friend: a flashlight. Trapping is a standard technique for certain pests, but other physical controls are sometimes necessary, such as the use of exclusion screens, or improving doors, windows and many other facility design features.
"Pesticide use should be a relatively small part of the big picture, but an important capstone on the pyramid. Sanitation, inspection and monitoring, good housekeeping and facility maintenance will all help simplify or minimize pesticide use. Proactive use of grain protectants, for example, is becoming more cost- effective and appealing than reacting to infestations with fumigation," says Heath.
Diagnostics
The last piece in the grain quality puzzle is proper diagnostics. Harmful mycotoxins, such as aflatoxin, can affect whether or not a commodity is marketable. The Food and Drug Administration (FDA) has established action levels for aflatoxin present in food or feed, and grain possessing levels higher than indicated are prohibited from selling.
According to the United States Department of Agriculture (USDA), aflatoxin can become a problem at temperatures of 80 to 90 F, but can survive in environments as low 40 F. The mold thrives in hosts containing high levels of moisture.
Any and all of the above mentioned measures (moisture management, aeration, temperature, pest control) can contribute to high toxicity levels. Dean Layton, vice president marketing and sales of EnviroLogix, says "Stressful conditions at critical stages in the crop's growth can make it vulnerable to the fungi that produce mycotoxins. Improper storage conditions can also promote mold and fungi growth and thus the mycotoxins they produce. Proper drying of grain soon after harvest and maintaining relatively dry and well ventilated storage conditions with adequate pest control are important in the prevention of mycotoxins."
Layton suggests taking multiple samples to ensure maximum grain quality of each truckload. "Since mycotoxins are not generally distributed evenly throughout the bulk grain sample, it is important to take multiple sub-samples to ensure representative sampling and accurate detection."
Quickly taking a sample of grain and determining its toxicity level is crucial in maintaining high-quality grain. The speed of the test affects grain quality because quick test times allow the trucks to remain in queue, thus allowing the grain receiving locations to avoid contaminating clean bins with a truck load that does not meet acceptable levels.
Layton explains how effective diagnostics affect a variety of entities dependent on high grain quality. "Being able to make rapid and accurate assessments relative to mycotoxin levels enables those receiving grain to quickly determine if the grain meets acceptable levels for different export, food and feed applications," Layton says.
Maintaining high grain quality can be easier with the help of expert advice on how to properly carry out moisture management, aeration, pest control and diagnostics. Each of these separate techniques depends on each other to protect and preserve grain quality for the end user, exporter or feed mill.
Safe Corn Storage* At Various Grain Moisture Contents and Grain TemperaturesStorage Air Temp.15% days20% days25% days30% days
Chart courtesy of Safegrain
24 C - 75 F11612.14.32.621 C - 70 F15516.15.83.518 C - 65 F20721.57.84.616 C - 60 F259279.65.813 C - 55 F3373512.57.510 C - 50 F4664817107 C - 45 F7257527164 C - 40 F9069434202 C - 35 F1,1401184225Pest Control PyramidPyramid courtesy of Industrial Fumigant Co.
Use Pesticide
Phys.Controls
Trapping
Monitoring
Inspection
Sanitation
ID Pests; Understand Biology
author: By Elise Sommerfeldt
Local Articles
Industrial Goods & Services
Home