This article first appeared with LinkedIn
In 2018, freeze-dried pet food accounted for 2.7% of the new product launches in pet and ended the year with a 1.4% share of total US pet food sales. Overall, the freeze-dried food category grew more than 20% in 2018 vs YAGO or roughly 5x faster than pet food in total. Yes, I know, it is off a much smaller base. My point is that consumer acceptance of freeze-dried products is growing, despite consumers not having a clear understanding of what freeze-dried is and what it is not. Full disclosure...I am the co-founder of Guardian Pet Food Company, and we make freeze-dried treats (WHoLE Prey Treats for Dogs) as well as freeze-dried food (MoRE Canine Food Bars). My hope is that after you read this article you'll have a better understanding of the freeze drying processes, what to look for (and lookout for) in products and an appreciation of why the freeze-dried format is a great option for your pets (and you).
SO WHAT IS FREEZE DRYING
I don't want to jump right in to GeekCon 5 so I'll give you the Cliff Notes version: Freeze drying is the process of taking something from a solid state (frozen) to a gaseous state (vapor) without the intermediary liquid step. Ok, I know...but it's only GeekCon2! If you look at the graph on the right, freeze drying is all about achieving the "tri-point" (where all three colors intersect). At different times during the 12-22 hour process (depending on what is being freeze-dried), the pressure and temperature is adjusted to maintain that tri-point. Before we get too far ahead of ourselves, there are a few steps that occur BEFORE the freeze drying; namely the FREEZING part.
If you are freezing an individual, whole food item (e.g. fruits, veggies or meat) the first step is to cut/dice the item, run a food safety process (HPP, pasteurization, chemicals or irradiation) and then freeze it. Options for freezing include a traditional freezer, a "blast freezer," or an IQF Tunnel/Spiral (Individual Quick Freeze). The key during this step is to avoid cellular level damage/"freezer burn" (see photos) and to make sure the entire piece is equally frozen throughout. You've now taken a 6oz. chicken breast, frozen it solid to stop any pathogenic bacteria and moved it into the sublimation chamber where the "freeze drying" will take place.
Foods that are freeze dried retain their original characteristics - color, shape/size, taste, texture and nutritional value. The products are shelf stable, lightweight and have minimal microbial concerns. The 6oz chicken breast will now weigh roughly 1.2oz but be the same in every other aspect. The most important benefit that cannot be overstated is the nutritional values. In the making of dry kibble, the extrusion process requires several things: high temperature/pressure to cook the food and kill pathogens and high levels of starches and carbohydrates to form the kibble. With temperatures exceeding 325 degrees Fahrenheit and changing from "dough" to kibble in less than 5 minutes, "continuous chemical and physical alterations to the ingredient mixture occurs. These changes include vitamin loss and protein denaturation (i.e., changing the protein's molecular structure)."
"In addition to lysine, other amino acids such as arginine, tryptophan, cysteine and histidine can also be affected by the extrusion process. Of particular importance may be the sulphur amino acids (cysteine and methionine) which are often limiting in diets for cats as these amino acids are susceptible to oxidation." - 2008 report by the Animal Nutrition Group at Wageningen University in the Netherlands
This is one of the reasons why you see so many artificial and synthetic ingredients in dry kibble. It is also why the digestibility of these brands is between 60-80%. As for the carbohydrates, they are a low cost source of energy (dry kibble is made up of 30-60% carbohydrates). When the dough/kibble passes through the die (cutter), it leaves the pressurized expander and the starches "puff" to the familiar "round, brown kibble".
HEAD TO HEAD
So how much of a difference is there between freeze dried and extruded kibble? While I can't speak to "all" freeze dried pet foods, this chart shows Guardian's MoRE Beef & Chicken Bar vs. a leading extruded kibble diet. While both show enough amino acids to meet/surpass AAFCO requirements for growth and maintenance, if you look at the items called out in the research quote you can see the difference. The extruded kibble includes synthetic amino acids that were added as a means to replace what was lost during extrusion!
ARE ALL FREEZE DRIED FOODS EQUAL?
Simple answer - NO! When looking at freeze-dried treats, what other ingredients are included and why? If you see a freeze dried treat ingredient deck that has "Chicken, Water, Sodium Phosphate, Salt And Carrageenan" or this "Chicken, Chicken Liver, Dried Peas, Dried Potatoes, Gelatin, Salt, Mixed Tocopherols (Preservative)" you gotta ask why? Sure they're freeze dried but they have ingredients that were solely added because it improved the yield. Freeze drying is expensive. A chicken breast will only give you a 20% yield of its wet weight. Blueberries will only give you a 10% yield. Hypothetically, if raw chicken cost you $0.70/lb, the freeze dried ingredient cost would be $3.50/lb PLUS the manufacturing costs. How do they improve that? Well they add dry ingredients and ingredients with starches. If you want the full benefit, then buy treats that say, "protein Freeze Dried Treat" and only contain that protein! What about freeze dried foods? The same logic applies. If you are starting with quality ingredients, why do you need to supplement the formula with added vitamins, minerals and amino acids? There shouldn't be any loss of nutrients or protein denaturation in the freeze drying process, so what gives? A leading freeze dried food proudly claims 44% Crude Protein in their formulation. When you dig a little deeper, you see that only 38% of the CP% (16.7% of the total) is made up of essential amino acids. The rest, well they are non-essential amino acids used to pump up the protein numbers. The dog doesn't need them, THAT'S why they're called "non-essential"! The other thing that some manufacturers do is suggest that you rehydrate the freeze dried food before giving it to your dog. First and foremost, it would be completely irresponsible of a pet owner not to provide a clean bowl of drinking water ad libitum. The idea of rehydrating the food is so that it will bulk up and make it more filling for your dog. Same reason most wet food diets are "formulated" to meet AAFCO. The ability for a dog to eat enough wet food to meet guidelines is not practical due to the food being 72% water (on average).
THE KILL STEP
The images to the right are meant to be illustrative of the effectiveness of a "kill step". Pet food manufacturers average a "Log 3 Reduction" which means that their process can eliminate 999,000 bacterial CFUs out of every 1,000,000 "presented". This is especially important when it comes to freeze-dried product because the food/treat SHOULD be, in essence, raw/not cooked. The higher the Log Reduction, the safer your dog's food! When researching your dog's food options, make sure you ask the manufacturer about their "kill step" AND their Log Reduction number! If/When they tell you, just think about their rehydrated (raw) food sitting in your pet's bowl. If only there was a food in a convenient form (like a Bar) that didn't need rehydrating, transitional feeding or even a bowl!! Yes, that is a shameless plug for MoRE Canine Food Bars!
After having spent almost 25 years in the pet industry, I ventured out to start a company with Dr. Ryan Yamka. Our founding principal of "Pets Before Profit" means we will create the best food we can with the pet's health coming first and foremost. We won't sub-optimize our formula for the sake of $0.03/lb more profit. Of all the manufacturing options out there, we opted for freeze drying because in aligns with that philosophy. We don't believe artificial and synthetic ingredients are needed, especially when freeze drying, which is why you'll recognize all of our ingredients without having to use an internet search engine. I could TELL you a lot more about our freeze dried foods and treats but I think it would be better to SHOW you. Give us a try and if you aren't impressed and your dog doesn't love it, we will refund your purchase price AND any shipping charges.