The Role of Rapid Test Kits in the Detection of Peanut and Almond Residues in Cumin and Spice Blends

Anthony J. Lupo, Director of Technical Services • Issued February 2015

Background In recent months there have been several cumin recalls involving seasoning blends containing high levels of undeclared peanut, and in some cases, detectable levels of almond. This has resulted in significant concern in several segments of the food and ingredient industry related to the safety of their incoming raw materials, and the tools available to accurately test them for these undeclared residues. The purpose of this document is to answer those questions that are currently top-of-mind for many in industry and to offer assistance with the tools and services that Neogen can provide.   Frequently Asked Questions

• How did peanut and almond residues get into cumin and spice blends?
• How high are the levels of peanut and almond being found in cumin and spice blends?
• How much risk does this pose to the allergic consumer?
• What tools are available for the detection of peanut and almond residues in cumin?
• How can the food industry be assured that these methods of detection are true peanut and almond contamination and not simply interference or cross-reactivity?

  How did peanut and almond residues get into cumin and spice blends? While there is no current direct evidence as to how these ingredients became contaminated, there are currently two working theories.

• The ingredients were adulterated for the purposes of economic gain with an inexpensive extending agent that contained significant levels of allergenic protein (e.g., peanut shells)
• In samples with moderate to low level (2.5–25 ppm) contamination, it is possible the ingredients may have become contaminated through commingling or accidental cross-contact with peanuts or almonds during processing, shipping, or storage.

  How high are the levels of peanut and almond being found in cumin and spice blends?

• Positive samples analyzed by the Neogen laboratory services team showed contamination levels ranging from 4.6 ppm total peanut to greater than 5000 ppm total peanut. However, it should be noted that several of the samples submitted to the laboratory tested with no detectable amounts of peanut or almond.
• Neogen is aware of samples tested in other laboratories with reported levels as high as 105,000 ppm total peanut.

  How much risk does this pose to the allergic consumer?

• It is believed that ingredients testing at very high levels (hundreds or thousands of parts per million) puts the allergic consumer at significant risk. Even if the ingredient is present at a relatively low inclusion rate like a spice, the dilution effect is not sufficient to consider it safe for the allergic consumer. Such levels even when diluted in finished foods are still well above published reference doses for many peanut allergic individuals.
• Ingredients testing at moderate to low levels (2.5–25 ppm) will be significantly diluted when found in foods at typical spice blend inclusion rates. A proper risk assessment should be conducted to determine if the level of risk is acceptable and the Food Allergen Research and Resource Program (FARRP) at the University of Nebraska is a suggested provider of this service.

  What tools are available for the detection of peanut and almond residues in cumin? Neogen has analyzed its range of test kits and found them to be suitable for this purpose. This included an evaluation of Neogen’s AOAC-validated Veratox® for Peanut Allergen, an enzyme-linked immunosorbent assay (ELISA) in a microwell format that fully quantifies the amount of peanut residue detected in parts per million (ppm), and Veratox for Almond Allergen, an identical test for the detection of almond residues. Also evaluated were Neogen’s Alert® brand microwell tests for peanut and almond. The Alert tests are based on the same technology of the Veratox tests, but screen samples at 5 ppm instead of fully quantifying. In addition, the Reveal® for Peanut Allergen Lateral Flow test kit is an effective screening tool for the presence of peanut residues in these sample types.

For companies that prefer not to do their own on-site testing, Neogen also offers a rapid laboratory testing service at its locations in Lansing, Mich., and Ayr, Scotland.   How can the food industry be assured that these methods of detection are true peanut and almond contamination and not simply interference or cross-reactivity?

• It is very uncommon for an antibody-based test kit to exhibit such strong positives (>5,000 ppm) when the cause is cross-reactivity or matrix interference. Typically these manifest in very low level positive results (<10 ppm).
• There are several examples of these ingredients reporting no detectable peanut or almond residues. Typically interference or cross-reactivity manifests itself in all sample of this type making non-detect results not possible.
• When positive results are diluted they exhibit a linear dose response. False positives do not dilute linearly.
• The same samples analyzed on several brands of test kits each with different antibodies exhibit similar results. Multiple test kits reporting similar results are rarely wrong.
• Well-known laboratories have taken positive samples and separated the proteins using gel electrophoresis and transferred those proteins to nitrocellulose. They were then challenged with human IgE antisera from known peanut allergic individuals and binding of those antibodies in molecular weight regions consistent with known peanut allergens.
• All evidence supports that these are true positive results.

  Conclusion Depending on your needs, Neogen is prepared to support the food industry with a spectrum of tools and services that have proven reliable for the detection of peanut and almond residues in cumin and spice blends.   To be clear:

• Although evidence suggests adulteration, this has not been proven.
• Neogen test kits have shown to be fit for purpose in this application.
• A full risk assessment should be conducted before declaring any product believed to be contaminated safe for consumers.