The Science of Shelf Stability: Why Processing Matters for Quality, Safety, and Pet Food Performance
RESEARCH & DEVELOPMENT - TECHNICAL POSITION PAPER
Leading with Technical Expertise - White Paper
Leah Lambrakis, Department of Technical Services
Why Shelf-Stable Food Exists
To deliver nutritionally complete food that remains safe, stable, and consistent over time without refrigeration, preservatives, or immediate consumption, a validated preservation method is required. Shelf stability is the result of that method: controlled processing designed to manage microbial risk, protect nutrients, and maintain product quality. Convenience plays a meaningful role, but shelf stability is ultimately science meeting necessity.
At its core, shelf stability exists because food safety must be guaranteed by the brand and manufacturer, and not assumed. A validated kill step, typically through thermal processing, ensures that harmful microorganisms such as Salmonella, Listeria, E. coli, and Clostridium are destroyed or controlled to meet defined safety targets. At Simmons Pet Food, our focus is centered on retorted and shelf-stable wet pet food. This process reflects the same scientific standard the FDA applies to thermally processed low-acid foods under the definition of commercial sterility: rendering food free of microorganisms capable of reproducing under normal non-refrigerated storage conditions, and free of viable microorganisms of public health significance (1). Without this step, the responsibility of safety shifts heavily on refrigeration, cold-chain integrity, rapid consumption, and prevention of contamination throughout the supply chain. Pet food formats that do not include a validated kill step require additional controls throughout ingredient sourcing, interventions, handling, and distribution to manage pathogen risk (2,3). Pets can become carriers of these bacteria, facilitating transmission within the household and posing risks to vulnerable populations, including infants, the elderly, and immunocompromised individuals (3,4).
The Science Behind Processing
Processing is a spectrum of technical and scientific methods, each designed to control specific variables, and in the pet food space, these include microbial safety, water activity, nutrient stability, texture, shelf life, aroma release, and digestibility. What separates one process from another is not marketing language but the mechanisms being applied, such as heat, pressure, time, vacuum, dehydration, refrigeration, or freezing. Whether a product is raw, frozen, retorted, extruded, freeze-dried, refrigerated, or high-pressure processed, the science behind the process determines what is controlled, what is reduced or eliminated, and what is preserved. For example, a raw frozen product relies primarily on freezing to slow microbial growth rather than a thermal kill step. Refrigerated products may incorporate validated interventions while still depending on cold-chain integrity to maintain safety and quality. High pressure processing (HPP) can reduce many pathogens without heat, but it does not achieve commercial sterility or reliably control spore-forming bacteria such as Clostridium; therefore, HPP foods typically require refrigeration or freezing (5). By contrast, retort and hydrostatic cooking apply validated thermal lethality to achieve commercial sterility, making food microbiologically stable at room temperature without preservatives, refrigeration, or rapid consumption timeframes. Extrusion technology, used for kibble, relies on heat, pressure, and rapid drying to reduce water activity to a level that inhibits microbial growth. Freeze-drying takes a different approach, removing water under vacuum and reducing microbial activity through moisture removal rather than heat. All of these formats are processed, but in different ways and for different outcomes.
This is the scientific reality that gets lost in consumer-facing messaging: processing is a technical tool and not a quality judgment. The better question is not, “Is it processed?” but, “Which process was applied, under what controls, and to what result?” Clear science language matters because processing directly determines what the product delivers: safety, nutrition, texture, and shelf life.
Nutrition, Texture, and Safety
Processing influences three core aspects of pet food: nutrition, texture, and safety. Each is created through carefully controlled tools such as heat, pressure, time, and water activity, all of which affect how ingredients behave and how the finished food performs. Protein is a good example; it is common to hear that heat “denatures” protein, but denaturation is not the same as destruction. Heat changes the protein’s structure, often unfolding it in a way that can make amino acids more accessible to digestive enzymes. In this sense, thermal processing can support protein digestibility while still delivering the essential nutritional value of the ingredient. Fat digestibility generally remains high through thermal processes such as retort and hydrostatic cooking. In some cases, shelf-stable thermal processing may also help protect fat quality by limiting prolonged oxygen exposure, compared to other formats where fats may have greater opportunity for oxidative change over time. Vitamins are more sensitive to processing, particularly many B-vitamins and vitamin A, but this is a well-understood part of formulation design. R&D teams account for these sensitivities through targeted supplementation and validated nutrient matrices, and their stability from the cook process to the end of the product’s shelf life. Nutrient quality must also be protected after cooking, as oxidation and microbial degradation can affect product integrity over time. This is where shelf-stable processing, combined with proper sealing and storage, plays an important role in preserving that nutritional quality.
Texture is one of the most influential aspects of the feeding experience. Processing plays a key role in creating texture, and each product format requires specific controls to deliver the intended outcome. Specific to wet pet foods, loaf and pâté products depend on a ground, structured matrix where particle size, ingredient form, protein-water-fat interaction, and thermal cook influence firmness, mouthfeel, and palatability. Shredded whole muscle meats require controlled protein inclusion and carefully managed heating and cooling steps to create fibers that separate naturally and uniformly. Chunks in gravy systems depend on a two-phase design, where both the formed pieces and the gravy must maintain their integrity without breaking down, separating, or degrading through the process. Aroma release and flavoring are also linked to processing, such that heat can drive flavor development through reactions such as Maillard browning, creating savory compounds that contribute to the overall sensory experience. Different product formats can deliver different sensory profiles, from mild to rich flavor notes, as well as cooked, and savory. For pets, particularly cats with highly sensitive olfactory systems, the interaction between aroma, texture, and mouthfeel can strongly influence acceptance, enjoyment, and repeat engagement.
If nutrition and texture are shaped by processing, safety is defined by it. In foods without a validated thermal kill step, safety depends heavily on cold-chain control, ingredient quality, sanitation, handling, and prevention of contamination throughout the supply chain. Shelf-stable wet foods are one of the most validated food systems in the market, as the process itself is scientifically designed, measured, and verified. Through controlled heat treatment, hermetic sealing, and validated processing conditions, shelf-stable systems deliver a high level of microbial safety and long-term product stability. Finally, process claims should be evaluated by how clearly they are defined and supported. Processing terms without regulatory or scientific definitions may sound appealing, but they provide limited clarity on what controls are actually in place. Evaluating pet foods by process ultimately means seeking transparency, definition, and evidence. Whether a product is fresh, frozen, freeze-dried, or shelf-stable is less important than whether its processing method has been designed, validated, and consistently executed to deliver safe, complete, and reliable nutrition.
The Future of Shelf Stable Innovation
The science of shelf-stable pet food continues to evolve, driven by advances in processing technology, packaging design, analytical tools, and changing consumer expectations. Shelf stability is not only about achieving commercial sterility, but includes preserving nutrition, elevating the texture, and enhancing the feeding experience in ways that feel modern, familiar, and trustworthy. Advances in thermal processing are a major driver of this progress. Retort systems continue to become more efficient and refined, with improved heat distribution, better temperature control, improved water conservation and shorter cook times. These improvements allow manufacturers to better protect nutrient quality, texture, and sensory performance while still delivering the proven safety of shelf-stable food.
New packaging formats are reshaping what shelf-stable foods can look like. Innovations in pouches, cups, sachets, thermoformed trays, and multi-phase packaging systems allow for layers, inclusions, visible ingredients, and dual-texture meals that were once more difficult to maintain through sterilization. These formats appeal to pet parents seeking variety and culinary-style designs, all backed by the safety, convenience, and reliability of a shelf-stable product. At the same time, manufacturers are adopting more data-driven technologies such as near infrared (NIR) analytical monitoring, digital batch records, and predictive modelling. These tools support more precise critical control targets, tighter quality control, and better consistency from raw material to finished product.
Consumer demand is also driving innovation. Pet parents increasingly expect products that feel closer to “real food,” with clean labels, visible and familiar ingredients, and textures that mirror what they might serve to their family. Many of the most successful innovations in recent years, including purées, broths, savory toppers, and multi-textured formats, reflect this shift. They are new product forms and feeding experiences designed around variety, enjoyment, and pet parent interaction during mealtime.
As processing technology continues to advance, the distinction between fresh and shelf-stable will become less about perception and more about design, and in how we use science to create food that is safe, nutritious, enjoyable, and trusted.
Closing: Leadership Through Science, Innovation, and Stewardship
As the conversation around pet food innovation continues to evolve, it has never been more important to strengthen our understanding of processing in science rather than perception. Shelf stability is an advancing platform that remains one of the most reliable ways to deliver complete and balanced nutrition at scale, and increasingly one of the most innovative. At Simmons Pet Food, this is where we lead. As one of the largest producers of shelf-stable pet food in North America, our scale gives us the ability to turn small improvements into meaningful gains in quality, consistency, and customer confidence. Through innovation and manufacturing stewardship, Simmons Pet Food will continue to advance the possibilities of shelf-stable nutrition.
Our Commitment – Leading with Technical Expertise – we are here to provide guidance and insights – do not hesitate to connect with us at Simmons Pet Food, petcomments@simfoods.com. We would love to hear from you and be part of your pet’s nutrition solution!
Literature Referenced
U.S. Food and Drug Administration. (2024). 21 CFR 113.3 - Definitions. Code of Federal Regulations, Title 21, Chapter I, Subchapter B, Part 113, Subpart A. https://www.ecfr.gov/current/title-21/chapter-I/subchapter-B/part-113/subpart-A/section-113.3
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