Dog Food Storage Mites

House or dust mites have long been recognized as a common allergen for dogs suffering from Canine Atopic Dermatitis, but dog food storages mites are more important that you might thought.

Several studies from the US and Europe have found that sensitization to dog food storage mites is even more common in atopic dogs than dust mite sensitivity. In fact, 94% of dogs with atopic dermatitis are allergic to dog food storage mites.

Canine Atopic Dermatitis

Canine Atopic Dermatitis is a very common allergic skin disease in which the dog's immune system develops antibodies to substances in the environment known as allergens. Atopic Dermatitis affects about 10% of all dogs.

Initially, symptoms can be seasonal, as the dog's allergies are limited to pollen, but over time most atopic dogs become sensitized to substances in their indoor environment--dust mites, molds, dog food storage mites, wool--and symptoms become a year-round problem.

Symptoms of Canine Atopic Dermatitis include:

1. Chronic itching, face-rubbing, and scratching.
2. Self-injury resulting in scabs, sores, and secondary bacterial infections.
3. Excessive licking and chewing of paws, belly, and groin area.
4. Watery eyes.
5. Red, inflamed ears with wax buildup that can lead to bacterial or yeast infections.
6. Hair loss.

Contact with allergens should be avoided where possible, which brings us back to the problem of dog food storage mites.

What Are Dog Food Storage Mites?

Storage mites are tiny arachnids found in grain bins and dry food containers. While there are over 150 different species, only about 20 are known to be allergenic.

Of those, the Acarus siro, Lepidoglyphus destructor, Blomia tropicalis, and Tyrophagus putrescentiae (mold mite) species are generally considered to present the biggest problem for atopic dogs.

The storage mites' bodies as well as their excrement are potent allergens. In addition, consuming dog foods contaminated with heavy mite infestations can cause digestive problems.

Acarus Siro Mite Coutesy Joel Mills

Under the "right" conditions, dog food storage mites can multiply quickly. Depending on the species, a single female mite can lay between 400 and 1000 eggs.

A generation can be completed in as little as eight days, but with lower temperatures and humidity, the life cycle increases to several weeks.

Some storage mite species (e.g. Acarus siro) go through a highly resistant hypopus stage during which the nymphes' bodies harden and develop small suckers on their underside with which they attach to beetles and other insects.

In a favorable environment, the mites can survive up to seven months in this state. All storage mites prefer warmth and high humidity; temperatures of around 25 degrees Celsius with 70-90% humidity are considered ideal for mite development.

Prevalence of Dog Food Storage Mites

Several studies have sought to examine the prevalence of storage mites in kibble and other dry foods.

Since grain is the preferred food of most storage mites, grain-based dog foods are more likely to be contaminated with mites.

In fact, storage mites are quite common even in cereal-based foods destined for human consumption. A UK study examining 571 cereal-based food products intended for humans found storage mites in 21% when opening the package shortly after purchase at a retail food store. After six weeks of storage in volunteers' homes, 38% were contaminated with mites.

A 2005 study examining twenty dog and cat foods of different brands discovered storage mites in three.

The effect of storage methods on mite contamination has been investigated as well.

Researchers in a 2008 study purchased ten different premium dry dog foods formulated specifically for skin disorders.

Upon opening the bags immediately after purchase, only one of the ten contained storage mites. The opened bags were then stored for a total of six weeks (the maximum length of time opened kibble bags should be stored) under two different environmental conditions.

They were not placed inside airtight containers. At regular time intervals, samples were collected from each bag and analyzed for the presence of storage mites.

At the five-week point, mites were discovered in nine out of the ten dry dog foods when the bags were stored under conditions ideal for mite development (temperatures between 21.1 and 25.3 degrees Celsius and relative humidity between 65.4% and 76.6%).

Avoiding Dog Food Storage Mites

The 2008 study tells us that mite infestations are a near certainty when dry dog foods are stored incorrectly. That's why it's critical to keep dog food bags in an airtight container and place the container in a cool, dark, and dry location.

In hot, humid climates, this may mean running an air conditioner or dehumidifier in the room where the dog food is stored. Temperatures below 15 degrees Celsius (60 degrees Fahrenheit) are ideal, but anything up to 20 degrees Celsius (68 degrees Fahrenheit) is acceptable.

Some storage mites are unable to develop when temperatures drop below 10 degrees Celsius, while others can tolerate temperatures as low as 5 degrees Celsius.

At 0 degrees Celsius, some mites enter an inactive state, but regain activity and breeding capacity when temperatures rise.

Since storage mites dislike dry climates, try keeping humidity levels below 15%.

Freezing dry dog food at -18 degrees Celsius (0 degrees Fahrenheit) will kill storage mites within three to seven days, depending on the species. Of course the dead mites' carcasses and droppings remain potent allergens, so freezing is not a complete solution.

Correct dry dog food storage is very important to avoid mite infestations. Purchasing smaller bags to reduce storage time after opening is also a good idea.

If your dog suffers from storage mite allergies, try not to keep opened kibble bags longer than 3-4 weeks, unless you're storing them in the refrigerator, freezer, or a vacuum-sealed pouch placed in cool, dark, and dry location (see Freezing Dry Dog Food for details).

Make sure you regularly clean not just your dog food storage container, but the entire area surrounding the container.

Don't allow crumbs or debris to accumulate, and take special care to vacuum cracks and crevices.

If you come across a mite infestation, either freeze the affected bag for a week or wrap it in several plastic bags and dispose of it outside the house.

Then clean the whole area with boiling water and a strong detergent. Allow to dry completely before placing new food or food containers in the area.

All Dog Foods Are Not Created Equal

Proper storage is crucial, but as we have seen, there's a chance that kibble is shipped from the manufacturer with storage mites already in the bag.

Inexpensive, grain-based dry dog foods (the kind available in grocery stores) are most likely to be contaminated with storage mites and should be avoided.

Super premium foods made completely without grain are your best bet, but even these kibbles can accumulate mites if not stored correctly.

That's because storage mites don't eat only grains. For instance, the very common mold mite, Tyrophagus putrescentiae, thrives best in foods with high protein and fat content.

For dogs with severe storage mite allergies, veterinarians often recommend avoiding all dry food and feeding canned foods or a homemade diet instead.

In hot, humid climates, this may indeed be the best option if air conditioning or dehumidifiers aren't available to keep storage areas cool and dry.

But while storage mites in dry dog food are common, the problem is far from universal--provided you purchase a high quality, preferably grain-free kibble and store it correctly.