A recent literature review analyzed the growth of storage mites on commercial dry pet foods and its potential to cause false-positive food allergy diagnoses in dogs. Canine atopic dermatitis is linked to the body producing immunoglobulin E (IgE) for allergens that are either ingested or inhaled. Common symptoms include itching, redness, and skin lesions caused by chronic inflammation due to licking, chewing, and scratching. House dust mites (HDM) from the Dermatophagoides genus are the primary allergens detected in atopic dogs.
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The review, published in BMC Veterinary Research, focused on whether allergens from storage mites might lead to misdiagnoses of food allergies. Researchers reviewed 87 articles, ultimately selecting ten from both laboratory and field studies. Notably, studies dating back to 1972 established that Dermatophagoides HDM could survive on dry dog food. More recently, in 2010, Tyrophagus putrescentiae storage mites were demonstrated to thrive on certain commercial kibbles, especially when mold growth facilitated their proliferation.
A 2015 study found that 55% of dog food samples stored in sealed bags became infested with these mites after three months. Mites entered the bags through faulty seals, while lidded containers remained uncontaminated. Further investigations revealed that T. putrescentiae preferred protein- and fat-rich diets, and their numbers increased when food was crushed and left in high humidity.
Field studies indicated that storage mites were generally absent in commercially available dry dog food. For example, tests on food stored under various conditions showed that while mites could proliferate under high humidity and temperature, they remained undetectable in newly purchased bags or food stored properly.
Conclusions drawn from the review emphasize the potential for storage mites to induce allergic responses in sensitized dogs. Given the allergenic cross-reactivity between Tyrophagus mites and Dermatophagoides HDM, care should be taken during food trials to minimize the risk of mite contamination. Using new, sealed food stored in temperate conditions could reduce the likelihood of experiencing false-positive food allergy diagnoses.