Mycotoxins for dummies, part 2: Spike and recovery

In the first part of this blog, we discussed the basics of mycotoxins and how to test for them. In this post, we’ll go over the spike and recovery approach to validating unproven products.

Unverified food commodities require validation from rapid tests for many reasons. Some contain complex matrices, containing compounds that interfere with the binding of the antibody and the target analyte. Other samples might just be difficult to test, because the extracted product is perhaps very viscous, for example. Some samples might be too acidic or too alkaline to be easily tested.

“A spike and recovery approach is commonly used to validate unproven products on rapid testing platforms,” said Neogen’s Spencer Jackson.

This method uses a mycotoxin standard of a known concentration, available from a laboratory supply vendor. Using this toxin standard, a product can be inoculated at specific parts per million (ppm) or parts per billion (ppb). When inoculated products are tested, an analyst can determine if the result is indicative of the designed spike levels.

There are a few advantages to this approach. For instance, if original recoveries of inoculated samples are deemed unacceptable, an analyst may alter their technique in attempt to improve recovery. Data from spike and recovery tests might even warrant the use of a correction factor that may improve accuracy, if recovery from spiked products proves to be consistently high or low.

“However, this approach is not without questions,” said Jackson. “Analysts must consider whether or not the tested product contains a natural contamination, and how that affects results. There’s also been research on how the contact time of inoculated samples impacts the recovery of spiked toxin.”

When determining whether rapid testing is the right solution, the difference between naturally occurring and artificially introduced analytes must be considered. This isn’t just true for mycotoxins, but also food allergens. If an analyst performs a spike and recovery of a product using an allergen spike solution, the test may demonstrate that the product doesn’t interfere with recovery of that solution. However, this wouldn’t indicate potential contamination within the production facility, as a whole new set of variables could be introduced. Because of this, it’s important to consider each point of potential contamination, not only the end product.

This blog post is adapted from a paper written by Neogen’s Spencer Jackson. For a full copy of “Mycotoxin Analysis: Spike and Recovery,” email ahammerly@neogen.com.

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