Engormix/Mycotoxins/Technical articles

Mycotoxins. Sampling and testing

Immunoaffinity Columns add Value to Onsite Sampling and Testing Plans

Published on: 9/15/2011
Author/s : Diego Montemayor, DVM (Vicam)
Batch Screening vs. Individual Lot Testing
Batch sampling and testing with ELISA kits has long been a popular solution to the practical challenges of monitoring and documenting mycotoxin levels in incoming shipments of raw materials intending for export or food and feed products. The appeal of this strategy stems from its budget and efficiency advantages. By running a large number of samples from a series of incoming loads on multi-well ELISA plates, agribusiness firms can easily screen a large number of lots while decreasing the price per test.
Judged solely in terms of these short-term gains, the choice of individual sampling and testing with immunoaffinity (IA) columns for onsite inspections may initially seem counterintuitive. Yet despite the somewhat higher initial investment in time and money it requires, this alternative approach may ultimately prove the more cost-efficient and effective mycotoxin control strategy over the long term.
Assessing the True Cost of Mycotoxin Risk Reduction Strategies
A sampling and testing plan that fails to address the specific analytic, business, and compliance challenges of raw materials buyers and traders poses serious risks at every stage of the value chain. Once shipments slip past inspection, the cost and complexity of managing the problem increase significantly. Food manufacturers and grain exporters that inadvertently blend contaminated material with clean lots can face consequences ranging from fines and dumped shipments to outright trade bans. In storage facilities and feed mills, misclassified lots can initiate widespread contamination that may ultimately prove impossible to control.
The Hidden Costs of Batch Testing
The true value of a sampling and test plan lies in both the quality of the data it provides and the availability of that data at critical decision-making points in the business cycle. A batch plan typically requires collecting samples from multiple daily or weekly shipments. That means the test results from those samples are unlikely to get to the quality control manager until after those incoming loads have been accepted or rejected. At that point, the value of the information is largely historical. It may alert managers to the presence of lots that need to be treated or rerouted to industrial applications, document compliance, or help identify procedural problems. Although the evidence from this historical record may help reduce future errors, it can´t undo the damage that´s already been done to the firm´s bottom line.
Minimizing the Risk of Uncertainty
In contrast, individual sample analysis with immunoaffinity (IA) columns offers a proactive approach to managing the risks of faulty acceptance decisions. Recommended by major international regulatory bodies, this rigorous sampling alternative addresses the most significant cause of miscalculations in mycotoxin analysis. Because mycotoxins tend to occur in scattered locations in bulk shipments, a tiny percentage of grains or kernels may harbor a high level of contamination, while most of the lot remains unaffected. As a result, testing small samples may yield a high rate of false negatives and false positives. Compared to ELISA methods, IA columns are a more cost-efficient method for testing a mixture of subsamples from multiple locations in a single lot. By providing a more reliable picture of the acceptability of the lot, this type of sampling plan empowers quality inspectors to stop the spread of mycotoxins at the buying point.
The use of IA columns also addresses another common source of analytic error. By interacting with sample components that are chemically or structurally similar to mycotoxins, the highly specific antibodies in some immunoassays can contribute to under- or overestimates of contamination levels. While this is a well-known problem with ELISA methods, sample cleanup with IA columns eliminates these chemical interferences. Used with a fluorometric reader, this method delivers accurate test results in the parts-per-range in little as 10 minutes, putting precise real-time data in the hands of decision makers when they need it most.
 
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