Freeze-dried pet food: the pros and cons

September 17, 2024
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We are firm believers and advocates of a fresh-is-best approach however, we understand that feeding an entirely fresh, raw diet simply isn’t convenient or accessible enough for everyone, all the time. Providing options for people that suit both their lifestyles and budget is our way of helping raw, premium nutrition find its way into as many pet’s bowls as possible. Freeze-dried raw pet food is one of these ways. 

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Freeze-drying of food is not a new technology and has been around since the early 1900’s, however it is relatively new in the world of pet food manufacturing. Freeze-drying is one of the most important ways of preserving heat-sensitive biological materials and is widely used in pharmaceuticals, nutraceuticals, as well as the production and stabilisation of food for both humans and pets [1].

Freeze-drying provides the convenience of dry food, insofar as it is shelf stable and can be fed straight from the bag. Where it differs is that it isn’t subjected to the extremes in temperature that processed pet foods have. Because of this, it is the far healthier, convenient pet food and treat option. 

Freeze-drying (also known as lyophilisation) is a two-stage process. The first stage quickly freezes down the raw material at temperatures as low as -40 to -70°C. Once the material is frozen, the water is removed from the material through gentle evaporation at low pressure and temperature. This phase is called sublimation. This process removes most of the water, leaving behind the rest of the raw material in a dormant and preserved state. This process is unique as the nutritional component of a food (or active component of a pharmaceutical) is retained while its shelf life is extended. This is because the relatively fast removal of moisture (when comparing freeze-drying to other drying techniques) preserves the integrity of the raw material while the removal of moisture renders the natural bacteria that would otherwise degrade the material over time, as dormant and unable to do so. Once the material is rehydrated, it returns to its natural state to be used as the biologically active raw material it once was [2].

Overview of the three-step process of freeze-drying. 

There are various types of pet food processing methods, developed to extend shelf life and increase consumer convenience and each of these processing methods has an overall impact on nutrition. A summary of these is as follows: 

Pet food processing – Most to least nutrition retained

Research is currently unclear on the impact of other cooking methods to extend the shelf life of pet food (think dog rolls, meatballs etc.) and this is likely hard to speculate as these cooked products are heated to different temperatures in different ways. What we can be confident of, is that these products are cooked at temperatures above dehydration and below tinner food, so we can speculate that nutrient degradation for these types of foods will sit between these two categories. The inclusion of synthetic vitamins, minerals and in some cases important proteins like taurine indicate that these supplements are replacing nutrients damaged during the production and cooking process. 

At Big Dog, we supply raw pet food because it is the highest in quality from a nutrition point of view, but because their processing is the least damaging to the nutrition found in fresh whole foods, we can provide these options as complete and balanced foods without the need for synthetic nutrition additives. 

The Pro’s of Freeze-Dried Pet Food 

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Convenience – Straight from the bag into your pet’s bowl, freeze-dried food is perfect for travel and treats when fresh raw food isn’t convenient or accessible. We generally recommend that water be added to freeze-dried food when being fed as a complete meal, or ensuring your pet has access to ample fresh water to drink from. 

Shelf Life – Food in its raw state needs to be used within a few days. Just like the meat we buy from the supermarket for our own consumption, fresh raw food goes bad within a few days – even in the fridge. The beauty of freeze drying is that the moisture found in raw food is removed to levels where the food is no longer susceptible to spoilage in the same manner as food in its raw state. The shelf life of the food is thereby increased without the need to use any nasty chemicals, high temperatures that can damage the nutrition in the food, or preservation techniques like radiation to sterilise the food [2]. 

‍Taste (or palatability) – Freeze-dried food is highly palatable for pets and is a fantastic option for anyone wanting to transition their pet from a processed diet to a healthier diet, but are struggling to entice their pet to eat it. As Australia’s first commercial manufacturer of raw food diets, we have found that that the longer a pet has been eating a heavily processed diet like kibbled or canned food, the harder the transition process may be. It’s like looking at the diet of a human who has eaten a highly processed diet for the majority of their adult life (think deep-fried carby, fatty foods; fish and chips, pizza, fried chicken and burgers), then is told they can only eat a healthy non-processed diet from now on (think lean protein and vegetables, salads, fruit and nuts). It takes time to adjust to such a big dietary change and begin to enjoy what healthy food tastes like. It’s the same with our pets and why we recommend our freeze-dried food as a great option to use when transitioning pets to a healthy raw food diet. Not because it’s heavily processed, but the removal of moisture does increase the palatability of the food. The texture, as a “dry food”, is also more similar to kibble so dogs that are used to a crunchy food often respond better to freeze-dried in the beginning. Over time, as your pet starts enjoying the freeze-dried food, you can begin integrating the raw food. 

If you have a fussy eater who you’d like to switch to a healthier diet but they simply look at their bowl and walk away, then consider freeze-dried food as an option. Even pets with poor appetites as well as picky eaters generally like the taste of freeze-dried food. 

Nutrition – When looking at different dried food options, freeze-dried food retains the highest nutrient content of any other type of processing. A 2021 study comparing the antioxidant levels of Black Goji Berries found that freeze-drying preserved 5.8 times more of the beneficial antioxidants than hot air-drying [5].

Even the most delicate nutrients, probiotics, contained within freeze-dried foods survive the freeze-drying process far better than they would, if exposed to heat. Heat destroys these beneficial micro-organisms, rendering their inclusion in the food to begin with, completely pointless so if you’re looking for a dry food option, rich in probiotics for your pet’s gut health and immune system, freeze-dried food is the way to go [6,7].   

Less Ick Factor – Not everyone enjoys feeding their pet a fresh, raw food diet (and let’s not even mention the smell that fills the room after a tin of wet pet food is opened… *gag*). Raw food diets are wet, bloody, smell like raw meat and they aren’t to everyone’s liking. For people who want the goodness of a raw food diet for their pet, without the whole raw-food-experience, freeze-dried complete and balanced pet food is a great alternative.

Transitioning – As mentioned when discussing taste, freeze-dried food is more palatable than fresh raw food. Although raw food is highly palatable for pets, especially if this is the only diet they know, when transitioning from a processed pet food diet, freeze-dried is the perfect gateway food.  It can also help to minimise waste as transitioning should be a slow process to get the pet used to the new flavour of the food, as well as minimising any tummy upsets that are common when people transition between different types of food too quickly. We recommend including only 20% of a new diet with meals for a few days, then increasing in increments of 20% every few days until the new diet is 100% of the diet. This takes roughly 2 weeks and for people with small pets, there is the potential of a great deal of wasted fresh food during this time. Freeze-dried food, because of its shelf life, can help alleviate this problem until raw food can be fed in greater amounts where wastage is no longer an issue. 

The Con’s of Freeze-Dried Pet Food


‍Cost – Freeze-drying despite being relatively quicker than air drying or dehydration still takes time and expensive machinery. For this reason, feeding a diet that is 100% freeze-dried (if the diet is complete and balanced and the ingredients are good quality) would be more costly than a fresh, raw food diet. Feeding partly freeze-dried with your preferred pet food product is a great way to provide extra nutrition for your dog without the cost of feeding a freeze-dried diet 100% of the time. 

Lack of moisture – Fresh raw diets are naturally rich in moisture and hydrating for the pet. They’re basically consuming water as part of their meals which is great for their kidneys and for overall hydration, especially in warmer weather. All dry food lacks moisture and while access to plenty of fresh drinking water allows the pet to rehydrate voluntarily, we do recommend adding water to freeze-dried food to rehydrate it back to its raw, high-moisture state. 

Not as much choice – Because of the cost to produce, there simply isn’t the variety and availability of options with freeze-dried foods in the way there is with complete and balanced raw food diets. A way around this is to co-feed some freeze-dried and some complete and balanced raw food to make up your pets varied diet. You may also decide to use freeze-dried food as treats or when travelling and use raw food the bulk of the time for meals. Choosing Big Dog freeze-dried dog food gives you the peace of mind that not only are you feeding a complete and balanced nutrient-dense product as a treat, but our mixed protein recipes also provide variety over and above the single-protein products on the market. 

How to Use Freeze-Dried Food

  • Treats
  • Transitioning 
  • Add to kibble to boost the nutritional quality of the meal 
  • Add to canned (wet) food to boost the nutritional quality of the meal 
  • Add to raw food to increase the palatability
  • When travelling 
  • A convenient everyday alternative to raw food if this is your personal preference

Freeze Dried Food Red Flags 

Just like any food, there are high quality and low-quality options. Unfortunately, when it comes to pet food, it’s not easy to differentiate between the two due to the lack of regulation in the industry and the use of often misleading marketing terms to attempt to confuse the buyer [9]. 

When choosing a brand of freeze-dried pet food, there are a few red flags to look out for:

Where is the product made? Products made in countries with higher comparative global pet food standards, like Australia and New Zealand for example, is an important marker of quality. Products made in countries with poor pet food standards on the global scale have been disproportionately involved in product recalls and pet illness. 

Where do the ingredients come from? Despite the lack of regulation in the Australian pet food market, the quality of fresh Australian produce is world-class and choosing a freeze-dried pet food made form Australian produce is a marker of quality. 

How many calories are in the product? This is less of red flag and more something to be aware of in a general sense. Depending on the calorie content of the treat, over-treating can lead to weight gain and health problems over time. It can be tempting to restrict food to assist weight loss but unless the treats being fed are a complete and balanced pet food, this may lead to nutritional deficiencies over time. So treat your pet responsibly or use a complete and balanced treat like Big Dog Freeze-Dried Bites so you can manage calories without negatively impacting nutrition.  

Is there added synthetic nutrition in your freeze-dried product? This can be a marker of poor-quality raw materials which need to be bolstered by synthetic nutrition to be considered nutritious. If you are feeding freeze-dried food as a complete meal, this is even more important to consider. The lack of degradation in the freeze-drying process means that when using high-quality, nutrient-dense raw materials, supplementation with synthetics shouldn’t be necessary [10].  

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References
  1. Institute of Food Technologies. https://www.ift.org/
  2. Trugo L and Finglas PM. The Encyclopedia of Food Sciences and Nutrition. 2nd ed. Academic Press; 2003.  
  3. Mohammadi X, Deng Y, Matinfar G, Singh A, Mandal R, Pratap-Singh A. Impact of Three Different Dehydration Methods on Nutritional Values and Sensory Quality of Dried Broccoli, Oranges, and Carrots. Foods. 2020; 9(10):1464. https://doi.org/10.3390/foods9101464.
  4. Tran, Q.D., Hendriks, W.H., and Van Der Poel, A.F.B. (2008). Effects of extrusion processing on nutrients in dry pet food. Journal of the Science of Food and Agriculture, 88(9): p. 1487-1493. 
  5. Wang Y, Fu J, Yang D. In Situ Stability of Anthocyanins in Lycium ruthenicum Murray. Molecules. 2021 Nov 23;26(23):7073. doi: 10.3390/molecules26237073. PMID: 34885653.
  6. Bolla PA, Serradell Mde L, de Urraza PJ, De Antoni GL. Effect of freeze-drying on viability and in vitro probiotic properties of a mixture of lactic acid bacteria and yeasts isolated from kefir. J Dairy Res. 2011 Feb;78(1):15-22. doi: 10.1017/S0022029910000610. Epub 2010 Sep 8. PMID: 20822567.
  7. Terpou A, Papadaki A, Lappa IK, Kachrimanidou V, Bosnea LA, Kopsahelis N. Probiotics in Food Systems: Significance and Emerging Strategies Towards Improved Viability and Delivery of Enhanced Beneficial Value. Nutrients. 2019 Jul 13;11(7):1591. doi: 10.3390/nu11071591. PMID: 31337060; PMCID: PMC6683253.
  8. https://www.petfoodindustry.com/articles/7995-freeze-drying-novel-protein-may-help-pet-food-palatability
  9. https://hunde.com.au/blogs/hunde/the-problem-with-the-australian-pet-food-industry
  10. https://www.dogsnaturallymagazine.com/freeze-dried-dog-food-the-pros-and-cons/