Pet food nutrition depends on the complete picture—ingredient quality, nutrient bioavailability, fortification, food safety controls, and whether pets eat enough to meet their needs—not simply on processing methods like heat, freezing, or air-drying.
- Processing serves multiple purposes: Heat, freezing, and drying reduce microbial hazards, improve digestibility, enhance palatability, and maintain product stability throughout shelf life.
- Heat is not inherently harmful: Protein denaturation and starch gelatinization from heat can improve digestibility and texture; excessive heat is the concern, not heat itself.
- Every preservation method has trade-offs: Freezing can cause ice crystal damage; freeze-drying still requires microbial controls and oxidation protection despite low temperatures.
- Food safety requires validation: The Food Safety Modernization Act (FSMA) requires processes to be tested, controlled, and validated—not simply labeled as gentle or minimally processed.
- Nutrition depends on the finished product: Nutritional value comes from ingredient nutrient content, bioavailability, appropriate fortification, oxidation control, and whether pets consume enough to meet their needs.
Before someone states the obvious, I will: This article is dry.
Not because pet food is dry. Not because the subject is uninteresting. And certainly not because food science has run out of things to discuss. It is dry because we have come to treat processing methods (with heat) as a shortcut for judging whether pet food is good or bad.
Depending on the narrative, frozen is better. Fresh is better. Refrigerated is better. Air-dried is better. Freeze-dried is better. Gently cooked is better. Cold-formed is better. Raw is better. And, apparently, anything involving heat is suspect. Increasingly, pet food marketing defines products by how they are processed, implying that the process itself proves nutritional superiority.
We have spent decades demonizing individual ingredients. Now we seem to be entering a new era in which we demonize processing methods.
Food science is rarely that simple. The purpose of processing is not to win a marketing argument. It is to transform ingredients into food that is safe, stable, digestible, palatable and capable of delivering the nutrients a pet needs throughout shelf life. That requires a more complete narrative than whether the food was heated (and at what level and duration).
The process is a tool
Drying reduces water activity and helps create products that remain stable during storage. Freezing slows microbial and chemical deterioration. Refrigeration provides another way to control microbial growth. Heat processing can reduce microbial hazards while changing ingredients in ways that improve digestibility, texture and palatability. Extrusion combines heat, moisture, pressure and mechanical energy to transform raw materials into stable, digestible food.
The central question is not “Which process is best?” It is “What is the nutritional goal of the product, and which combination of ingredients and processing will achieve it?” The value of the finished food depends on ingredient nutrient content, bioavailability, nutrient losses during processing and storage, appropriate fortification, palatability, stability and microbial safety.
Process claims are not simply marketing claims. They intersect with food safety.
The Food Safety Modernization Act, or FSMA, established a preventive approach to food safety in which facilities identify hazards and establish preventive controls designed to minimize or prevent those hazards. Depending on the product and process, those controls can include sanitation, environmental controls, thermal processing, refrigeration, storage and other measures. Importantly, FSMA does not establish one universal temperature that makes every pet food safe. Food safety depends on the characteristics of the food, the hazards identified and the validated controls used to address them.
The process must demonstrate that it achieves the intended food-safety objectives. That may involve microbial challenge studies, thermal-process validation, water-activity measurements and shelf-life confirmation. That is different from saying, “Our food is not heated as much, so it is somehow better.” A lower-temperature process may offer advantages, but it also brings challenges that must be controlled. Cold-forming still must deliver cooked starches to ensure the dog or cat does not experience loose stools and diarrhea. A process is not safe because it sounds gentle; it is safe because it is controlled, tested and validated. Those controls must extend through delivery to the consumer.
Heat is not the enemy
Consumers already understand that processing changes food because they use these methods in their own kitchens: grilling, baking, boiling, frying, microwaving, freezing and refrigeration. No one expects a raw steak and a grilled steak to have the same texture, aroma or chemistry.
Heat provides energy, and that energy can alter proteins, starches, fats, vitamins and other components. The magnitude of those changes depends on the ingredients, moisture, temperature, time, pressure, oxygen exposure and other processing conditions.
Protein
Proteins have complex three-dimensional structures maintained by numerous chemical bonds. When heat is applied, increased molecular movement can disrupt some of those interactions, causing proteins to unfold. This is denaturation. The protein's three-dimensional structure changes, but that does not mean its amino acid sequence has simply disappeared or that the protein has ceased to have nutritional value.
A raw egg white is translucent and fluid. Apply heat and its proteins unfold and interact, producing an opaque, firm structure. Consumers see these changes in their kitchen.
Processing can similarly alter proteins in pet food. In some circumstances, these changes can improve digestibility, texture or palatability. Under excessive or prolonged processing conditions, additional reactions can occur and some nutrients may become less available. Denaturation is a structural change, not a synonym for nutritional destruction.
Starch
Starch provides an even clearer example of why heat cannot simply be labeled harmful. Starch granules have organized structures, and different starch sources vary in their proportions and arrangements of amylose and amylopectin. When starch is heated in the presence of water, the granules absorb water, swell and lose portions of their original crystalline organization. This process, known as gelatinization, can make starch more accessible to digestive enzymes and is critical to digestibility.
Heat, moisture, pressure and mechanical energy can also transform starch into structures that contribute to expansion, crispness, thickening and other desirable physical characteristics. Excessive heat or processing time can negatively affect texture and other quality characteristics. In baking, for example, excessive surface drying can contribute to casehardening, producing an extremely dry exterior while moisture remains trapped inside.
The objective is appropriate processing, not maximum processing.
Fats and oils
Heating can cause fats to melt and become more fluid. More importantly, prolonged exposure to heat — particularly in the presence of oxygen — can accelerate oxidation, especially in unsaturated fats. Oxidation can produce compounds associated with rancid flavors and odors and can reduce product quality. Extreme or prolonged heating can also produce additional degradation products, including polymerized materials.
This is familiar in household cooking, where oils can begin to smoke and produce noticeable changes in aroma and appearance. In pet foods, the relevant variables include temperature, time, oxygen exposure, fat composition, antioxidants, packaging and storage conditions. The finished product depends on the process and how well those variables are managed.
Maillard reaction
Processing becomes more complicated when dry heat is linked to Maillard reaction products. The Maillard reaction is a broad group of non-enzymatic reactions involving reducing sugars and amino acids. These reactions contribute to the color, aroma and flavor associated with foods such as toasted bread, roasted coffee, brewing beer and seared meat. The chemistry is extensive and involves numerous intermediate compounds. Sugar specificity is critical: reducing sugars such as glucose, ribose, xylose and fructose can participate because of their reactive carbonyl groups. This matters because not every protein reacts in the same way, and not every sugar participates equally.
Advanced glycation end products, or AGEs, can form through later stages of glycation chemistry and oxidation. However, it is overly simplistic to assume that every heated pet food produces the same AGE profile, or that eliminating heat eliminates the issue. Temperature matters, but so do moisture, time, composition, reducing sugars, amino acids and oxygen. This chemistry cannot be reduced to the claim that “low temperature is better.”
Freezing/freeze-drying
If heat is not inherently bad, the absence of heat is not inherently good. Freezing is an effective preservation tool because it slows many microbial and chemical processes but freezing still changes food. Ice crystals can disrupt cellular structures and influence texture after thawing. During prolonged storage, moisture migration and exposure to dry freezer air can contribute to freezer burn and quality deterioration. Oxidation can also affect susceptible fats. None of this makes freezing a poor process. It simply illustrates that every preservation method has consequences that must be managed.
Freeze-drying offers another useful example. The process freezes the product and removes water primarily through sublimation — the transition of water from a solid directly into vapor without first becoming liquid. Because product temperatures can remain relatively low, freeze-drying can help preserve characteristics such as flavor, shape and texture. But low temperature does not mean nothing happens chemically or microbiologically. Once water is removed, fats and other components still need protection from oxygen and other factors that influence shelf life. Microorganisms are not necessarily eliminated simply because water has been removed; some may remain viable in a dormant state. Freeze-dried foods still require appropriate microbial controls, water-activity management, packaging and storage.
Bioavailability, nutritional balance, over-fortification and prudent-fortification
This is where the conversation needs to move beyond processing labels and back to nutrition. The chosen process can affect nutrient losses, including vitamins, and can change bioavailability of nutrients to positive or negative. Additional fortification may be necessary to deliver key nutrients that are more easily destroyed over time, temperature, storage conditions or even light. Prudent fortification may be necessary to deliver key nutritionals not found in the chosen ingredients (e.g., L-carnitine or taurine). All these changes cannot be made by those just using a software package but should be designed with the direction of qualified professionals from synergistic sciences.
These goals require chemistry, nutrition, engineering and food science that go beyond a processing claim on a label. The focus should be the finished product and what it delivers. Is oxidation controlled? How is microbial safety established? Is the product nutritionally balanced, or is it over-formulated with certain nutrients, such as fat or calcium? Does the pet eat enough of the food to meet its nutritional needs? More of a nutrient should not be assumed to be better; it may simply be more and in many cases it could be harmful.
Those questions tell us far more than whether the package says freeze-dried, frozen, gently cooked, air-dried, cold-formed or raw. The pet food industry has spent years turning ingredients into villains: corn, soy, byproducts, grains, gluten and preservatives. Processing should not become the next target.
Consumers deserve a more informed conversation. Processing matters, but it is not nutrition. Temperature is not nutrition. Manufacturing method is not nutrition. A meaningful nutritional evaluation considers the entire product: nutritional and ingredient targets, ingredient nutrient content, formulation, appropriate fortification, processing, digestibility, bioavailability, nutrient stability, microbial safety, oxidation control, shelf life and whether the pet will eat enough to meet its needs. In the end, nutrition is proven by the quality, safety, stability and performance of the finished food — not by a marketing claim that one branded process is inherently better.
George Collings is president and founder of Nutrition Solutions since 2005. With over 40 years of experience, Collings is a uniquely board-certified nutritionist and food scientist in both animal and human sides of nutrition. Nutrition Solutions’ team of experienced professionals are uniquely qualified to support new and existing nutrition businesses (pet, animal, human) with innovation and development in every phase of business.
