Freeze dried dog food is attracting more attention than ever before, with new products coming to market, and an increasing number of owners either supplementing their dogs’ diets’ with freeze dried, or switching over entirely. But history teaches us that popularity cannot be taken as an assurance of the nutritional value of a product – and particularly so when it comes to dog food!
This introduction to an interesting food option is intended to give you enough information that you’ll be comfortable deciding whether freeze dried dog food is worth a try for your dog!
Understanding Freeze Drying
The process of freeze drying begins with a food being blast-frozen, also known as snap-frozen, and then subjected to a vacuum, with the air pressure lowered sufficiently to ¹turn moisture particles into gas. The objective is to keep intact the nutritional properties of the food, while preserving it and significantly increasing shelf life. Freeze drying accomplishes the first of these goals – retaining nutritional value – by avoiding the application of heat, and the second – of preserving the food, and increasing shelf life – by removing most of the moisture.
Rather than evaporating away the moisture through boiling at high temperature, freeze drying utilizes the principal that evaporation happens at lower temperatures with thinner, or low-pressure, air. For example, it takes 212 degrees F. to boil water at sea level; but only 180 degrees to do so on a high mountain! At 30 kilometers in altitude, water will boil at room temperature!
So we see that, while boiling a liquid typically involves heating it, such is not always the case. For, by lowering the atmospheric pressure, the boiling point of a liquid is correspondingly lowered.
Boiling, therefore, can be defined as: The rapid vaporization of a liquid which occurs when its temperature is at a level where the vapor pressure of the liquid equals the pressure exerted on the liquid by the surrounding atmosphere.
Freeze Dried’ Compared to Fresh Raw Food
Freeze-dried raw food goes a long way towards providing the best of both worlds! That is, it offers the nutritional and health benefits of raw food, while at the same time providing the convenience of kibble and other ready-to-serve commercial foods. This convenience consists of ease of handling, minimal preparation time and a long shelf life.
Is there any benefit to whole, unprocessed raw food, that your dog would not get from a freeze dried raw diet? The lack of bones to chew may be the only obvious drawback. Nutrition wise, a good freeze dried raw diet will include a full measure of ground bone, providing all the health benefits of the bone’s calcium and other nutrients. Chewing on bones provides a range of benefits, amongst which are jaw exercise, a satisfying outlet for excess physical energy, and a good teeth-cleaning and gum-massaging regimen. But the solution is simple: Provide your freeze dried raw fed dog with some raw meaty bones to chew on. Failing that, some well-chosen chewy toys would compensate – at least to a degree.
How else might whole, unprocessed raw food prove a better choice than its freeze dried counterpart? Preparing your own raw food from scratch clearly provides complete freedom in choosing ingredients, and customizing a diet to precise individual requirements. But for most situations, where a dog is not on an entirely unique diet, prescribed possibly for health reasons, a ready-made freeze dried product should provide great nutrition. Plus, if needed, other ingredients may be added as supplements to the diet when serving.
Nutritional Value of Freeze Dried Foods
An important key to insuring that the maximum nutritional value of food remains after processing, is to avoid the application of heat. Hence, if you eat a raw carrot, you’ll be better nourished than with a cooked one; and a lightly cooked carrot will give more value than an over-cooked one. Herein lies one of the great attractions of the freeze-drying process! In World War II, the military began using freeze-dried food for rations, and subsequently it became the standard food for astronauts. Its light weight made for easy packaging and shipping, plus it gained a long-extended shelf-life while retaining most, if not all, of its nutritional properties. The majority of vitamins and minerals keep between 95% and 100% of their nutritional value when freeze-dried. Contrast this with cooked foods, where nutrient losses can amount to between 25% to 75% and more!
At the end of the article I’ve provided a ²chart from the USDA, 2013, which shows maximum nutrient losses to foods from a variety of processing methods. The figures are done as a comparison to unprocessed raw foods. For our purposes, compare figures in the “Freeze” column to the corresponding ones in other columns.
Are There Other Ways of Preserving Raw Food?
Since raw food would no longer be “raw” if heat-processed, we are only concerned in this article with non-heat processing methods.
High-pressure pasteurization, or HPP is a USDA (United States Department of Agriculture) approved method for preserving and sterilizing foods. Also known as Pascalization, after the French scientist, Blaise Pascal who documented the effects of pressure on fluids. The process involves applying pressure in excess of 50,000 lbs. per square inch to food for about 15 minutes, resulting in the inactivation of mold, yeast and bacteria. Some raw food products are HPP processed.
The HPP method of processing is controversial amongst raw food purists. This is for two reasons:
HPP eliminates many bacteria; yet, it should be noted that not all bacteria is bad. Digestive processes in animals and humans depend on the function of healthy bacteria in the GI tract to break down and digest food; therefore, eliminating all bacteria can be problematic.
This second objection is more general in nature; it is that, arguably, a food subjected to HPP can no longer truly be considered raw; given the resulting change to its natural state. The FDA does not allow a food producer to make the claim of “fresh” in the case of products that have been HPP treated. However the terms “raw” or “organic” may still be used for HPP processed products. Notwithstanding this, in the interests of disclosure and/or fending off potential lawsuits, it’s likely that most companies using HPP processing will disclose it by name on their labelling, or use terms such as “cold pressure treated”, perhaps to sound more benign to those with concerns over HPP!
The Cost of Feeding Your Dog Freeze-Dried Raw Food
A quick review of prices on a variety of freeze dried dog foods in one of the larger US pet supply retailers showed prices in the range of $2.00 to $2.50 per oz (at the time of writing this article) when buying the larger of the package choices. Finished food, once hydrated with water bulk up to about 4 times their dried weight. Therefore, a food costing $2.50/oz would yield ready-to-serve food at a cost in the region of 64 cents/oz. Follow meal quantity guidelines on the food package for your dog’s life stage.
Given the relatively high cost of freeze dried raw dog food, it’s worth keeping in mind that compared to every non-raw dog food available the freeze dried product offers much more nutritional value per ounce. Serving portions therefore are smaller, using fewer ounces per meal to feed a dog. I’d like to do a detailed cost-analysis of various foods, but that’s a topic for another article!
Keeping Within a Budget
In the event that feeding your dog his or her full meal portion using a freeze dried product exceeds your current budget, simply provide the portion of freeze dried food you are comfortable with, and supplement as needed with a kibble dog food of the best quality possible.
¹The process of sublimation, where a substance is transitioned from a solid phase to a gas phase, without going through the liquid phase.
²Nutrient losses resulting from food processing methods, compared to raw food:
|Typical Maximum Nutrient Losses (as compared to raw food)|
|Retinol Activity Equivalent||5%||50%||25%||35%||10%|