7 Practical Tips for Successful Palatability Tests Design

We’ve all been there. We just got the results from our last round of palatability tests, and we wish we would have done things differently. We wish we knew the moisture content of the competitive product. We should have chosen a different control. Maybe we should have had more animals. We didn’t, though, and now it’s too late. Decisions that were made with good intentions, usually with the intent of saving time and money, end up costing us more time and money.”

What can we do differently? We can prepare better and think ahead, which anyone can do, but few actually do.
 
First, we need to keep in mind the limitations of the tools we can use. The sensory analysis of diets by pets is mostly based on preference and/or acceptance tests.¹ Such trials can be performed in in-home panels of untrained pets and in so-called “expert” panels of animals conditioned to discriminate foods since they were young. In preference testing, animals have the choice between two different diets presented simultaneously, whereas, in the acceptability tests, only one type of food product is available. Both approaches have advantages and constraints.² None of them are perfect, but they are still the two most used techniques to assess the palatability of an improved or brand-new pet food finished product.

Since these are the practical tools, we have to work with, we believe it’s important that our customers, brands, and co-manufacturers use them as effectively as possible and gain the most knowledge and understanding of the investment they made in these tests. Moreover, because the Covid-19 pandemic has strengthened the bonds between pets and pet parents, it is crucial to deliver foods, treats, and toppers that cats and dogs will not only eat but enjoy as well.

Here are seven useful rules that I created for myself during my 14 years working on palatability projects. If you follow them, it will help you design meaningful palatability tests, and get the most useful information you can from the resources you have.

 

1) Start with why

Asking yourself the right questions is an essential first step in designing the best palatability approach. Write down what questions you are trying to answer and be as specific as you can. Share these questions with your colleagues and customers to gain alignments on the goals. For example, if you are launching a new product, think long and hard about the competitive landscape. Then ask yourself if you really need for it to outperform the competition, or if maybe it is more relevant to focus solely on its acceptability. Clarifying your goals will help you determine if you should conduct preference tests, acceptability tests, or both.

2) Begin with the end in mind

Once you have a clear idea about which type of tests are the most relevant to your needs and you have your palatability test design written, imagine the results of these tests. Write them down. Then ask yourself which conclusions and subsequent actions they might trigger. In my experience, this is a step that not many invest in, but one that would most likely help you improve your test design. Often, it brings forth a realization that one or more tests aren’t relevant to achieving your goals; or it could shed light on a test that may have been missed and would help you interpret your results better. Either way, having the discipline to follow this process can help you save money or significant time in the development process

3) Be proactive

Evaluate and test your products before sending them to the palatability testing facility. Make sure your R&D and quality teams approve the products before they ship. I cannot stress this enough. Because palatability tests are expensive, resource-intensive, and take a significant amount of time to put in place, be thorough during the preparation process.
In practice, this means making sure the product you send to get tested is a good representation of the final product. It means getting basic analytical tests done before sending the products to the testing facility. Specifically, the two types of results most customers wish they had performed are moisture and oxidation tests. Moisture, directly or indirectly, can have a significant impact on palatability, and having a representative sample sent for moisture analysis ahead of time can help when interpreting your palatability results. For example, the water content of super-premium cat kibbles generally ranges from 5.5% to 7%. When they have the choice, cats prefer the driest kibbles. They can detect a difference of humidity between two kibbles as low as 0.5%, and a decrease in moisture often leads to a significant increase in consumption. The same is observed with dogs, except they prefer higher moistures. These observed preferences should be considered when testing palatants options side-by-side. Additionally, oxidation can be an influencing factor in palatability results. Therefore, it is recommended to measure peroxide and hexanal. This is most critical if the kibble is being shipped uncoated, with the intent to coat it with different palatants later.

4) Less is not more in the palatability world

Decide wisely on the number of animals you want your tests to be performed with. Even if most of us have not received any formal palatability or statistical training, people have the right intuition that the more subjects you have in your testing protocol, the more accurate and representative your results will be. For example, if a customer tells their marketing team that 75% of the dogs preferred the new formula, most are under the impression that they have achieved a strong win. Except this may not be true if only four dogs participated in the “study”. Similarly, if the study was conducted with 100 dogs, there is higher confidence in the results. While four dogs may not be robust enough and palatability trials with 100 dogs may not be feasible, it gets difficult to draw the line in the middle. Adding to the difficulties is the cost of palatability tests (usually evaluated per animal and per day) and the subsequent temptation to use a smaller number of animals.

5) Plan to control potential bias

Leading palatability suppliers usually have their own panels of trained cats and dogs. They have rigorous protocols in place to ensure that their animals show preference toward higher-performing foods. When an animal has been identified as biased or handed (tendency to eat only on one side), they are retrained, and if their performance does not improve, they are adopted out. Additionally, as all pet parents know, sometimes our furry companions get sick or do not act normally, which can lead to abnormal under or over-consumption. In these circumstances, the data gathered from these animals should not be considered when performing the statistical analysis of the test results. When hiring a third-party panel, one can understand that there can be some conflict of interest at play. If you request a 30-dog test, it is expected to see 30 results in your palatability result report.
 
But what if some dogs show handedness, or what if some dogs were sick and not eating normally?
Third-party testing facilities do not usually share details about these factors, especially about biased subjects. It puts brands in a difficult situation because handedness is something that happens frequently, and can cause the statistical interpretation to over-represent parity, especially with tests being performed with a lower number of animals, such as 20.
 
What can we do to remediate this limitation?
An option is requesting tests to be performed for the third day. When looking at an individual’s intake data, if you notice that a dog ate mostly food A on the first day, then mostly food B on the second day, it may lead to suspicion of handedness. If this behavior is observed on the same dog in a different test, it’s likely that those suspicions are true. When this happens, and it more than likely will, having data for the third day can help verify the hypothesis. In this example, if that specific dog ate mostly food A on the first day, mostly food B on the second day, and then reverts to eating mostly food A on the third day, you should probably ask for the statistical treatment to exclude data generated by this animal. Adding a third day is a monetary investment but depending on how critical it is for you to have accurate results to base your decision on, it is usually money well invested.

Palatability testing cost ranges based on 2021 leading US third-party facilities’ prices

6) Chose a meaningful testing location

In the US, the choices are more limited than in Europe, for example. The most convenient location for conducting palatability tests is to outsource to a third-party kennel or cattery, which uses a controlled environment. While it’s the most convenient and fastest method, conducting palatability tests this way has its limitations, starting with the limited variety of ages and breeds of animals. We also observed that results obtained in controlled environments could not be easily repeated in IHUT (in-home use test) settings.
Considering the cost of palatability tests, it’s important to ask ourselves if it’s wise to invest in tests that might not accurately represent how your products will perform in your customers’ homes. Additionally, there are growing concerns surrounding the ethics of using third-party panels, where animals are confined in very small spaces for most of the day. If your customer base is sensitive to these types of moral choices, you should take this aspect into consideration during your decision-making process.

7) Pay attention to details

When I started my journey in the palatability world, 90+% of palatability tests were conducted on kibbles, and less than 10% were dedicated to canned foods and treats, combined. However, there are now more pet food product types than ever, from broths to freeze-dried and frozen foods and toppers. While most palatability tests today are still performed on kibbles, and we previously discussed the importance of controlling certain factors such as moisture and oxidation, other variables should be considered when testing more novel product types. For example, we once worked on a project testing two different types of frozen foods. One was sold in a plastic tub and required the entire unit to be thawed the day before. The other was sold in small nuggets that only required for the product to be thawed 30 minutes prior. We initially requested the testing facility to follow each product label instruction, but the results were surprising. We ordered a second round of tests and changed the food preparation protocol to allow for both foods to be presented at the same temperature. The subsequent results were significantly different. We concluded that we weren’t measuring palatability performance during our first series of tests, we were measuring cats’ aversion to cold foods!
The key learnings were to pay attention to all the details that might have a positive or negative impact on palatability. Some feeding facilities won’t think about these details for you, so you have to be in the driver's seat, or hire a team that will do it for you!

References

1. Koppel, K. Sensory analysis of pet foods. Sci. Food Agri. 2014,11:2148–2153. [Google Scholar]

2. Griffin, R.W., Scott, G.C., Cante, C.J. Food preferences of dogs housed in testing-kennels and in consumers' homes: Some comparisons. Biobehavioral Rev.1984,8:253–259. [Google Scholar]

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About the Author

Émilie Mesnier holds a master’s degree in food science from France and has been dedicated to the pet food industry since 2007. She is committed to leverage her almost two decades of experience to pets and animals in general, the pet food industry, efficiencies, palatability, environmental stewardship, responsible consumption, and international expansion. Passionate about continuous improvement, sustainable living and innovation, Émilie actively applies her knowledge to both her professional and personal life. In early 2025, Émilie will return to her roots in France to bring BSM Partners’ full suite of consulting services closer to clients across the European market.