By: Athena Gaffud, DVM 

Types of Pet-Food 

There are three broad categories of pet food products based on moisture content: wet, dry, and complementary treats as described by the GAPFA. 

Wet pet foods are produced by mixing the ingredients and cooking them within a container such as a can, tray, or pouch. Though no extreme heat is applied, the food in the container remains sterile until opened. 

On the other hand, dry pet food is processed either by baking or extrusion. Dry and wet ingredients are mixed together to form a dough. The extrusion process includes thermal and mechanical treatments, where the dough is heated under pressure and pushed through a die machine that cuts the kibbles. The kibbles are then dried, cooled, and spray-coated. Some of the benefits of extrusion are improved palatability and durability of the final product. However, it also causes undesirable effects on nutrient bioavailability and digestibility.

The study of Montegiove et al in 2022 showed that dry pet food consisting only of chicken fresh meats has the highest content of soluble protein; it also contains more essential amino acids, branched-chain amino acids, and Taurine, as well as a greater quantity of monounsaturated and polyunsaturated fatty acids. It was concluded that a fresh-meat-based formulation is a preferable choice for dry pet food.

Battle of dry kibbles: Extrusion vs Baking 

The first application of extrusion to food products was in the 1930s. Because of several benefits, including economy and versatility, it has been widely used in the food processing industry (Gibson and Alavi, 2013). Kibble production involves mixing of ingredients to form a dough that is pumped into an extruder. In this process, food materials are forced to enter through a small opening with the use of screws. The high-pressure, high shear, and high-temperature environment created by the screws, encased in the barrel cook the food as it is being forced through the extruder. Due to the release of pressure and conversion of water into steam, the cooked materials puff upon exit. All these could happen in less than a minute in a continuous process. (Gu et al, 2017). 

Another process widely utilized for the production of dry pet food kibbles is baking. In this process, all dry ingredients are weighed in batches and transferred to a mixer. The dough is pressed into a die with the desired shape and depth during rotary molding. The shaped kibbles pass through a tunnel oven with temperature settings ranging from 350 to 450°F for 7-15 min or until the kibbles have reached a shelf-stable moisture content. Compared with extrusion processing, baking is a much lower throughput process. Unfortunately, there is not much available scientific

data that quantifies the differences between the transformations and properties of the final products between extrusion and baking processes for making dry pet food kibble. Therefore, the difference of scratch gelatinization between the two had been explored by Gibson and Alavi in 2013. Their study concluded that starch gelatinization in extruded kibble ranged from 90 to 100%, whereas in baked pet food kibble was ≤ 60%. Gelatinization of starch increases starch digestibility leading to increased glucose availability in the bloodstream. The risk of obesity increases if a pet continually consumes these excess calories. Graham (2015) defined “gelatinization” as a process of cooking starch causing conformational structure changes. This starch acts as a glue and ready source of energy for the dog. 

At Bully Max, extrusion is not an option. We reap the benefits of slow-cooking. 

Slow-cooking or gentle cooking is a general term for cooking methods that do not involve protein denaturation and are non-destructive to other nutrients in food. Gently cooked dog food is a subset of fresh dog food that applies only the minimum amount of heat needed to kill any pathogens and bacteria present in the food. This results in pet food that preserves the optimal level of nutrition without putting your dog at risk of food poisoning or other diseases. While raw food has its own benefits, it also imposes some risks of infection of harmful organisms. This risk is eliminated in slow-cooked dog food with the use of non-destructive heat. The main difference is they’re able to take full advantage of the wholesomeness of their ingredients by ensuring that as little of it as possible is destroyed in the cooking process. Having said that, a slow-cooked meal has the “best of both worlds” between plain fresh food and raw food.