The drought of 2012 may be over but the impact from the drought is still being felt on our farm every day. A lot of last year’s corn crop had aflatoxin in it. As a result, we have to test every load of corn we purchase to feed to our hogs. I have been asked several times what the test involves. When I explain it to people, they are surprised at the number of steps it takes to perform the test. One test will take approximately 8 minutes from start to finish.
This is a picture of a sample of corn we took from a truck today. As you can see, the corn kernels look small but that was normal for last year’s corn. To look at the corn, one would think it was good corn.
Once we draw a sample of corn from the truck, the first thing we do is test the corn for the moisture level. As you can see in the picture below, the moisture on this sample was 14.1%.
We consider corn dry at 15% (and anything under 15%), if corn gets over 16% we have a difficult time grinding it and getting it to flow smoothly through our augers and bins. Corn high in moisture will hang up in the bins and feeders and not flow properly. It’s very important we have dry corn for the feed.
The next step in the testing process is to grind the corn into a meal. We grind our corn with a coffee bean grinder but we have used a kitchen blender before too. Once we grind the corn, we measure out 50 grams on a scale. This has to precise, too little or too much will alter the test results.
Once we have 50 grams of corn, we add 100 ml of a water/methanol solution (as shown below) to the ground corn and we blend it at a high speed for exactly one minute.
The next step in the process is to separate the solids and liquids. We do this with a coffee filter as you can see below. It takes about 45 – 60 seconds to get enough liquids in the jar so we can perform the actual test.
Once we have our liquid sample, we draw out 1000 ul with a pipette of the solution and add it to a column. Then we add 1000 ul of diluent to the column. Next we push air through the column to filter the solution through what looks like cotton in the column. We catch the sample in a test tube as you can see below.
Once we have the sample in the test tube, we draw 500 ul out with the pipette and we put this into a new test tube. Then we had developer to the solution. Once we add the developer, we have about 10 seconds to get the test tube in the machine for an accurate reading.
Before we can put the test tube in the machine though, we have to make sure the test tube is free of lint, dust and finger prints.
And this is the reading from the sample of corn that was pictured above. As you can see, just because the corn looks good, it doesn’t mean it’s safe to feed our pregnant sows.
If this corn had been fed to pregnant sows, the pregnancy would abort due to the high aflatoxin level. This is why we are so particular with purchasing high quality corn for our hogs.
We can’t afford to make a mistake at the feed mill. Testing each load has slowed down our corn line which frustrates the truck drivers delivering the corn to us. We cannot afford to compromise our bio-security though, one load of corn that tests too high can have a lasting impact on our production at the sow farm. We try to be as efficient as possible in performing the test while being considerate of other people’s time. In the amount of time it takes to unload 1,000 bushels of corn, we can have another load of corn tested so we aren’t delaying the drivers unless they are the first person in line. If your the first person in the line, you have to wait about 8 minutes to unload.
Hopefully the 2013 corn crop will be better and we won’t have to test every load of corn that we purchase for aflatoxin. Until then, this is how I will be spending my days, testing corn!