Freeze-Dried vs. Air-Dried - What's the Difference?
8/13/2018 - By ZIWI
An often-asked question we receive from pet parents who are considering feeding ZIWI Peak Air-Dried food is how our product differs from freeze-dried foods. To understand the difference, it’s helpful to understand what causes foods to spoil in the first place.
Unless it is frozen or preserved in some manner, meat “spoils” or “goes off” very quickly, due to the presence of microorganisms, such as mold spores and bacteria. These microorganisms cause proteins and fats to break down, releasing toxins into the meat. They also multiply, eventually reaching levels that can cause illness or transmit disease.
In pet food production, there are many different ways to preserve meat and other food ingredients. The most common is to cook the food at high temperatures - the method used to create dry kibble and canned foods. Less common preservation methods include freeze-drying and air-drying. Most “Alternative to Raw” pet foods are produced using one of these less-common methods.
Freeze-drying and air-drying both work by eliminating the moisture required for microbial growth. Here are simplified explanations of both:
Freeze-Drying: Raw ingredients are frozen, then placed in a strong vacuum, where the temperature is raised slightly. This causes the frozen water to sublimate -- that is, it turns straight from ice into vapor, skipping the liquid phase, and separates from the remaining solid matter. Because all but about 3% of the moisture is removed, freeze-dried foods usually require rehydration before serving.
Air-Drying: Raw ingredients are placed into drying chambers, where air is continually circulated, slowly and gently evaporating moisture until a maximum level of 14% is reached.
Both methods result in shelf-stable, nutritious foods with great palatability; however, ZIWI’s unique process of air-drying produces some additional benefits:
- Lower Cost to Feed: The high nutrient density results in smaller serving sizes and the cost per ounce is lower, so ZIWI air-dried costs 40+% less to feed than leading freeze-dried brands.
- Easy to Feed: ZIWI Peak Air-Dried offers scoop-and-feed convenience, which means it can be fed straight from the bag without having to add water and wait for it to be absorbed.
- Safe and Hygienic: Our process eliminates harmful pathogens, such as mold spores, E. coli, salmonella, and listeria. This is especially important for people or pets with weakened immune systems, the elderly and the very young.
A family-owned company, ZIWI crafts our air-dried recipes in our own private kitchens, using 100% New Zealand sourced grass-fed meat and sustainably-sourced seafood. Based on a whole-prey model, our recipes contain 96% meat, organs, and bone, including 3% New Zealand Green Mussel, for natural glucosamine and chondroitin. We add no grains, wheat, rice, corn, potatoes, peas, lentils, glycerins or other fillers. ZIWI recipes are formulated to meet the nutritional levels established by the AAFCO for all breeds and life stages of dogs and cats.