Artificial flavors in pet food formulation

Using additives as a component of pet food diets can serve various purposes. They ensure food longevity and safety, and maintain the texture and color of pet food after a prolonged period of storage. An additive may be used to prevent water activity, spoilage and oxidation of sensitive ingredients that require additional protection.

Another use of additives is to increase the palatability and flavor of the diet. Flavor is an important sensory feature for both dogs and cats, and will ultimately determine whether the food – no matter how well- balanced and nutritious – is consumed in its entirety.

The rules and regulations

In the EU, additives in pet food must be authorized under existing EU regulations and stated on the product label. Regulation is not straightforward and, according to the European Pet Food Industry Federation (FEDIAF), there is no obligation to declare additives, with no legal maximum limit.

Additionally, the additive’s name does not need to be given on the label, just the functional group it belongs to: preservatives, antioxidants, flavorings or colorants.

Improving palatability

Pet food companies invest a considerable amount of time, effort and resources in improving diet palatability, especially some extruded veterinary diets where there is a need to significantly reduce protein (chronic kidney disease, cystine or purine urolithiasis) or fat (chronic pancreatitis). Or to formulate a diet with hydrolyzed protein, where the addition of synthetic amino acids is necessary to balance out the composition.

Palatants improve flavor, aroma, texture, appearance, or a combination of these, to increase overall preference and acceptance of a wet or extruded diet.

Flavor enhancers affect palatability in 2 different ways. There are enhancers that affect ‘first choice’ – the first food chosen in preference tests. These flavors mostly affect olfactory perception and improve the attractiveness of the diet. Perhaps more important are flavor enhancers classified as having a ‘continuous choice effect’. This reflects acceptance of pet food on a continuous basis.

Types of tasty ingredients

Flavor enhancers can be characterized as synthetic or naturally derived ingredients. This division is sometimes unclear, as naturally derived substances might be extracted at a significant level of processing that can ultimately influence the integrity of the extracted ingredient.

Natural flavors often added to pet foods are extracts from fish, poultry and beef meat and organs, while artificial flavors are usually developed to mirror natural ones. Natural palatants or flavor enhancers predominantly used in extruded or wet pet food are referred to as ‘digests’, enzymatically digested proteins that enhance the meaty flavor.

Other frequently used natural palatants are yeasts, essential oils, fats, plant oils, organic acids, spray- dried animal plasma, protein hydrolysate, distillate, or any product of roasting and heating.

Flavor enhancers that do not meet the criteria of natural palatants are classified as synthetic flavors and fall under the same regulation. Although many artificial flavor enhancers are regarded as safe, and widely used, some are considered to be controversial.

Debate on the negative effects

Additives in the form of pyrophosphates, or phosphate salts, are often used in cat food to increase palatability by intensifying the taste of amino acids. Some of these nutrients cats do find particularly tasty.

There is some debate about whether there are any negative effects associated with this artificial flavoring agent. It is a known fact that excess inorganic phosphorus may cause sustained kidney damage. Research shows that a high intake of inorganic phosphorus compounds (such as NaH2PO4) may affect indicators of renal function in cats (Dobenecker et al., 2018).

A 2021 critical review by J. Mark Craig on feed additives and artificial flavors raised concerns about the potentially overlooked health effects of some artificial palatants, such as cinnamic aldehyde (cinnamaldehyde), monosodium glutamate, trehalose, and artificial vanilla flavoring. The research was published in The Journal of Small Animal Practice.

From synthetic to natural

Despite official agencies giving assurances on safety, data to back up the claims is limited. Therefore, it would be wise to work towards replacing synthetic additives, where possible, with more natural, widely used, and readily available palatants.