Physical Properties of Wet Pet Food

There are obvious differences between the processes of quality control in the human and pet food industries, the main one being the lack of feedback from the pet sensory panel. 

However, quick rejection of undesirable food provides enough motivation for pet owners and pet food manufacturers alike to provide animals with the correct food.

Wet foods make up the majority of products sold in pet shops, consisting of meat and liver with a range of other ingredients. The textures are solid, puréed, shredded, cuts, cubes and blends of human food ingredients. These are much more palatable than dry foods to most cats and dogs - neither dogs nor cats are drawn to sticky foods but both show a preference for wet food rather than dry.

Cats are even fussier than dogs about the texture of their food. The downside is that stools in the litter box are generally softer and smellier if the foods are not formulated correctly, providing more motivation to work on the texture of the food (as well as the nutritional content).

In the pet industry, some aspects of the food must also appeal to the owner feeding the animal – the smell, appearance and texture must all be pleasant and not off-putting. These are all important to the animal eating the food too, and taste must also be desirable. As well as this, all food meant for animal consumption has imposed safety and nutritional targets. These put a limit to the number of options available when putting together the formulation process.

After determining the parameters necessary for a high quality product, it is usual to use texture analysis techniques to determine the measurable properties. Stable Micro Systems offer many different testing options, some of which are outlined here.

Most wet cat and dog food is packaged in a rigid can or flat square tin, all with lids that are peeled off. A quick and easy test of the food’s firmness is the use of a Ball Probe pushed into the flat surface by the Texture Analyser loading arm. A firmer food will provide more resistance (shown as a higher force) against the probe.


The majority of wet foods contain several different textures held within a jelly or gravy matrix. This presents a textural challenge as a single point penetration test in different areas of the food will give different results. However, Stable Micro Systems offer a Multiple Puncture Probe that provides an average of many areas, providing more repeatable results. Probes can be removed for cleaning and can be replaced easily if damage has occurred.

Some dog foods are sold packaged in a sausage shape wrapped in plastic film. These can be tested using the multiple puncture mentioned above (if a flat surface is presented to the probe), or the sample can be cut using the Blade Set, giving an assessment of the sample hardness and the energy required to cut through.

Before production, many ingredients are tested in isolation to monitor their quality individually. For example, gelatin is widely used in many wet (and dry) pet foods as an easily digested, low calorie ingredient for added protein and elasticity (to control chewiness and firmness). The Gelatin Bloom Test is a standard and is offered by Stable Micro Systems. The test gives gel strength, bloom strength, force to rupture and elasticity data.

Lastly, raw pet food is becoming increasingly popular. It is perceived as healthier alternative to standard pet food, and has been pushed along by the recent trend of raw food in human diets. The above testing techniques are even more important for raw food analysis. The taste of the food is automatically different so it is crucial to keep the texture as similar as possible to standard food, to prevent rejection.Contact Stable Micro Systems today to discover the full range of Texture Analysis solutions.

---

For more information on how to measure texture, please visit the Texture Analysis Properties section on our website.

The TA.XTplus texture analyser is part of a family of texture analysis instruments and equipment from Stable Micro Systems. An extensive portfolio of specialist attachments is available to measure and analyse the textural properties of a huge range of food products. Our technical experts can also custom design instrument fixtures according to individual specifications.

No-one understands texture analysis like we do!

To discuss your specific test requirements, click here...