ST. LOUIS — Pet food sales continue to increase globally, especially in developing countries. Pet food owners are increasingly looking for better quality and alternative pet foods that are less processed compared to the conventional extruded kibble or wet food currently available. This alternative pet food category, which utilizes new processing techniques — including cold pressed, baked, air-dried, gently cooked, frozen, freeze-dried and raw food, to name a few — has seen a lot of growth in recent years. Using these alternative processes rather than traditional extrusion or retort techniques requires formulators to understand not only how the production process works, but also a myriad of associated factors when developing pet food.

The pet food market is constantly evolving. Currently, consumers are demanding more transparency, better nutrition, custom nutrition, and even humanizing how pet food should look or what ingredients are used (i.e., ingredients that are familiar or sustainable). To meet these market trends, formulation scientists need to keep up to date with these market trends, so that pet food not only meets the need of the pet but also that of the pet owner.

Formulation scientists not only need to understand basic pet nutrition but also the requirements to comply with regulatory guidelines for pet nutrition, including those outlined by the Association of American Feed Control Officials (AAFCO) and the European Pet Food Industry Federation (FEDIAF). The regulatory guidelines for dogs and cats have specific nutritional requirements and depend on their age (puppy/kitten or adult maintenance). Thus, the formulation scientist needs to ensure that the product is balanced and meets all the necessary nutritional requirements.

In addition to proper nutrition, if the food is marketed in the United States, the formulation scientist needs to follow AAFCO guidelines to support potential product claims. If the product contains animal-derived ingredients, claims could include the conditions under which the animal was raised and must be indicated as such. For example, claims such as “cage-free,” “free-range” or “grass-fed” can be used with the properly sourced ingredients.

In addition, the formulation scientist could design a product following the AAFCO guidelines with a claim that describes the name of the product. For example, the claim term “recipe” means at least 25% of the named ingredient was used in the product, but the claim term “with” means that the product only contains 3% of that named ingredient.

Regardless of the claim, the nutritional adequacy statement on all products must comply with the AAFCO requirements and the food must be designed to ensure the guaranteed nutrients are met until the end of the product’s shelf life.

Ingredients and nutrients

Formulation scientists also face the ongoing challenge of choosing the right ingredients. Ingredients available for use in pet food range from those characterized as “human-non-edible pet food grade” to “human-grade” ingredients, such as those that could be found in the grocery store. In the United States, ingredients are defined by AAFCO and are listed on the label in the order of predominance.

The formulation scientist needs to have an in-depth understanding of the nutritional composition of each ingredient, how processing affects the nutrients of the ingredient, and the potential interactions among the ingredients. The latter may have a positive or negative impact on the bioavailability of the nutrients when the food is digested by the pet.

Additionally, the formulation scientist needs to be aware of the availability of the ingredient, including considerations regarding the seasonality of the ingredient or availability following possible disease outbreaks such as avian influenza A (H5N1). The cost of the ingredient must also be considered.

Furthermore, safety standards of the ingredient need to be evaluated as some ingredients may contain naturally occurring environmental contaminants (such as arsenic, lead, mercury or cadmium) or toxins — grains could contain fumonisin, aflatoxin, mycotoxin or vomitoxin — which could influence the pet’s wellbeing.

The processing puzzle

How the food is manufactured creates an additional technical challenge for the formulation scientist. Depending on how much heat is generated during each step of the process — grinding, mixing and drying — the heat-labile nutrients could be destroyed. The formulation scientist needs to take into consideration any nutrients that could be destroyed during processing to ensure that the food delivers proper nutrition up to the end of the product shelf life.

Processing can affect nutrient bioavailability as well, and the formulation scientist needs to take this into consideration. For example: lycopene in tomatoes becomes more bioavailable with cooking. However, high heat treatment can reduce certain nutrients such as the amino acid lysine, making the protein less nutritious.

Palatability is a measure of food preference which is associated with factors such as taste, aroma and mouthfeel, as well as macronutrient composition and product form. In the case of dogs and cats, what they like is not the same as what the pet owner perceives. Keeping this in mind, the formulation scientist needs to focus on what really attracts pets to prefer one food over another.

The formulation scientist needs to consider many factors that affect palatability including raw materials, formula composition, and the effect of processing. The quality and freshness of ingredients also has a tremendous impact on palatability. The formula composition drives palatability. For example, high-fat and low-fat products will attract pets differently. The type of process — extrusion, retort, gently cooked or other alternative processes — and processing parameters also have a major impact on the texture and flavor of the finished product.

Digestibility reflects how much of a food’s nutritional value is absorbed into the blood stream and used to nourish the pet’s body. A formulation scientist needs to understand the importance of ingredient selection and processing parameters when it comes to digestibility. For example, a food that is high in fiber or undercooked carbohydrates could potentially reduce digestibility and absorption of essential nutrients.

Shelf life refers to the length of time that a product can maintain its quality, including product safety (microbial), nutritional content, and organoleptic characteristics (including smell, texture and color). The main challenges for the formulation scientist are to ensure that at the end of the product’s shelf life, the food is nutritionally stable, organoleptically acceptable and safe for consumption. In order to verify these factors, formulators usually conduct a shelf-life study. Key parameters that are monitored include degradation of key nutrients, fat oxidation, microbial growth and sensory evaluation.

In summary, pet food formulation is not an easy task. Those charged with that job — formulation scientists — need to consider many factors when developing pet food. Complying with regulatory and product safety parameters, as well as delivering proper nutrition may seem simple enough, but disregarding the factors previously noted could lead to deleterious consequences, including product reformulation, product withdrawal from the market, or, even worse, a product recall. Any and all of these results could have a major impact on the company’s bottom line.

Susy Tejayadi, Ph.D., has more than two decades of experience spanning product development, nutrition, regulatory, and food safety and quality. She spent nearly 12 years with Instinct Pet Food in various R&D, food safety and regulatory roles. She also spent more than six years as a product development manager with Hill’s Pet Nutrition, and served as principal scientist with Mead Johnson Nutritionals for seven years. She is the founder and president of Tailored Pet Food Solutions LLC, a consultant firm providing services in product development, pet nutrition and regulatory compliance.

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