Without accurate test results grain segregation is impossible. The process starts with a representative sample of the load that needs testing. According to Michael Prinster, chief operating officer of Romer Labs, using the right equipment is essential to obtaining a good sample. "Pneumatic probes are the ideal tool for sampling because you can control the probe in multiple locations in the trailer," says Prinster. "It's in your best interest to know what kind of quality you're bringing into your facility, so upgrading to more sophisticated probes is well worth the cost."
After taking multiple probe samples totaling approximately five pounds, they must be ground together to form a composite, which is then sub-sampled for testing.
Once the proper sample is taken and the aflatoxin test is conducted, the elevator can determine whether it will accept or reject the grain. Their next responsibility is keeping it free of mycotoxins during storage.
While mycotoxins can never be completely eliminated, storing grain properly will help maintain grain quality and manage mycotoxin levels. Drying the grain before emptying it into a bin is the first step toward keeping mycotoxins from becoming a problem. According to Pfeiffer, mycotoxin growth halts once the grain's moisture content reaches less than 14%.
Permanent storage bins or silos are the ideal environment for keeping grain free of mycotoxins. "Temporary storage situations can increase the potential for aflatoxin formation because it exposes the grain to moisture, heat and wind," says Prinster. "I recommend storing in a closed, permanent bin to try to maintain the appropriate moisture level."
If the grain had a high level of infection to begin with, Pfeiffer says not to store it for an extended period of time because the quality may worsen over time if the mycotoxin spreads. Throughout the course of the storage period, Pfeiffer recommends mycotoxin infected grain should be tested on a monthly basis to gauge the quality until it's sold.
However, if the initial test results showed little or no aflatoxin, there is no need to test frequently. As long as the grain is stored properly, kept at the appropriate temperature, and maintains a moisture content of 14% or less, it is not likely that aflatoxin, or any other mycotoxin, would form.
Preventive Pest Management
Taking mycotoxin prevention methods can potentially kill two birds with one stone. Many of the steps taken to prevent the formation of aflatoxin also help prevent pest infestation. Grain pests, such as grain borers, moths and weevils, can potentially ruin the quality of an entire silo of grain. Being proactive and detecting pests early are both key to avoiding a widespread pest infestation.
According to Frank Arthur, research entomologist with the USDA-Agriculture Research Service, there are two types of pests: primary and secondary. Primary pests feed directly on the interior of the kernel and completely develop, from egg to larva, inside the kernel. Examples include the lesser grain borer, the rice weevil and the Angoumois grain moth. Secondary pests live their entire life cycle on the exterior of the kernel.
The rusty grain beetle, sawtoothed beetle and red flour beetle are all secondary grain pests.
Both primary and secondary pests can be controlled by taking an integrated pest management (IPM) approach. The keyword in IPM is integrated. This means the program utilizes a variety of pest-control measures, rather than relying on one method (primarily fumigation) to handle a pest infestation.
Doug VanGundy, director of specialty product development for Central Life Sciences, explains the main components of an IPM program. "It's a programmed approach to pest control including sanitation, exclusion, pest monitoring and chemical treatment. An integrated approach keeps the pests out and the grain quality high, and can reduce the need for costly fumigations."
Bin sanitation should be an integral part of any IPM program. The broken grain and dust that come off the grain create a food source for the pests. If the bin is not free of fines and grain dust after emptying, the insects will enter and continue their lifecycle.
Pest management experts recommend completely cleaning the bin and all equipment inside the bin, such as belts and elevator legs, before filling it again.
After thoroughly cleaning the bins, the grain is safe to enter the bin. At this point, an IPM program may include the application of a protectant insecticide applied as the grain is loaded into storage, such as Central Life Sciences' Diacon II.