Achieving consistent nutrient distribution in pet food begins long before the kibble is formed — it starts with how a premix is designed, according to Dr. Sofia Wilson, companion animal nutritionist at Trouw Nutrition, who presented at the Petfood Forum 2026 Tech Talk Stage.
Wilson noted that the lowest-inclusion ingredients in a pet food formula are often the most critical to animal health. In a 10-kilogram bag of dog food, for example, only about 19 grams of vitamin premix must be evenly distributed throughout the finished product. Within that premix, vitamin E accounts for roughly 4.8 grams, vitamin A for 1.1 grams and folic acid for just 0.19 grams.
"Imagine trying to evenly distribute less than half of a gram of nutrient across an entire bag of cat food," Wilson said. "Precision at that scale is not just difficult — I would say it's nearly impossible."
That challenge is precisely why premixes exist, she said: to pre-blend high-potency micro-ingredients so they can be uniformly incorporated into the final food. Wilson added that unlike livestock or human nutrition, where animals cycle through different feeds regularly, a single pet may consume one bag of food over six to eight weeks — a window long enough for toxicity or deficiency symptoms to develop if nutrient distribution is inconsistent.
Four components of a well-designed premix
Wilson outlined four components of a well-designed premix.
- Active ingredients. The targeted nutrients must be selected for the right form and potency, and must remain uniformly dispersed throughout the premix. Differences in particle size, shape, density, reactivity and flowability can all cause segregation — both in the mixer and during handling and storage.
- Soft carrier. Fine vitamin powders require a carrier material to bind and disperse them evenly. Rice hulls are the industry standard, Wilson said, though alternatives such as pea fiber or Miscanthus grass are used for grain-free, U.S.-sourced or non-GMO formulas. Effective carriers typically make up 20–40% of the premix formula, with a minimum of 15%, and should have a particle size of roughly 20–80 mesh, a high surface area-to-volume ratio and a rough surface texture. Rice hulls, for example, have a cross-hatched structure that provides crevices where fine powders can settle. Carriers should also be low-dust, non-hygroscopic and non-electrostatic.
- Diluent or densifier. Inert ingredients are used to adjust the density or concentration of a premix without contributing carrying capacity. Calcium carbonate is the most commonly used diluent, though potassium chloride, sodium chloride and trace minerals are also options. Wilson said particle size selection matters here to limit segregation relative to other premix components.
- Dust suppressors. Typically oils added at 0.5–2% inclusion, dust suppressors are applied as a coating on the carrier to act as a binding agent, improving adherence of fine particles and increasing the overall integrity and uniformity of the premix. Mineral oil is widely used; vegetable oils such as soy or sunflower oil can also be used but are more prone to oxidation. Wilson noted that dust suppressors serve an additional purpose in worker safety by reducing airborne dust and electrostatic charge in premix production facilities.
Wilson illustrated the impact of premix design using microscope images. A premix with approximately 39% actives, 60% carrier and 1% oil showed good uniformity and integrity. A second premix — heavily concentrated with actives and only 13% carrier, with no mineral oil — showed visible segregation, with vitamin E accumulating in one area and riboflavin separating out in another.
"Just adjusting the components of your premix can really help to improve the uniformity and prevent segregation," Wilson said.
