November 14, 2014


Author: Punyatoya Mohapatra

When a pet rejects a food he once ate enthusiastically, we may assume he doesn't feel well. But it may be the food that is “off.”

Like us, our canine and feline companions can smell and taste when food has exceeded its ideal shelf life. Most commercial pet foods are formulated to remain stable for 12 to 18 months. This range can be maximized by a synergistic palatant that enhances product taste, masks off flavors or helps control chemical reactions such as oxidation. Conversely, conditions like heat and humidity can hasten physical, chemical or biological changes that affect palatability.

Tracking Changes
When the palatability of a pet food declines over time, some sleuthing may be required to determine the cause. Is it a shelf life issue related to the product and/or palatant—or something else, such as conditions during transit or storage? As AFB International analytical chemistry manager, one of my roles is getting to the bottom of questions like these.

At AFB, we provide the value-added service of analyzing customer products or raw materials for physical and chemical changes over time. The process usually starts with a root cause analysis to identify key flavor parameters that might inhibit or sustain palatability over the product’s desired shelf life. Then, at regular intervals, we track those parameters using analytical tools such as electronic nose and tongue (ENT) to measure aroma and taste and gas chromatography mass spectrometry (GCMS) to determine chemical changes.

In certain cases, we also can accelerate a product’s shelf life by increasing the environmental temperature and humidity in a controlled chamber. As a result, we can reduce the amount of time required to test the stability of flavors.

In conjunction with these lab tests, we perform two-bowl tests with pets whose eating behaviors tell us whether the product remains consistently palatable over time. Together, the results construct a picture of what, if anything, is changing in the product and how pets are reacting.

A Deeper Look
Such studies can benefit customers by identifying any stability or palatability issues with their own product, as well as how their product stacks up against the competition.

A recent customer study looked at concerns about a product’s palatability and stability. After initial analysis, we proposed a new palatant, then conducted a carefully orchestrated 12-month study to compare the new diet/palatant combination against the customer’s existing product, as well as two key competitor products. Over the year-long study, we measured:
Relative palatability, which showed the new palatant had superior palatability to the previous palatant on the same diet
Stability, which indicated the new palatant/diet combination’s flavor composition was consistent throughout the study across three palatant lots
Competition, which revealed two competitor diets tracked using the same parameters were less consistent over time than the customer’s proposed diet/palatant

Armed with this knowledge, the customer was able to select the new palatant, confident it would perform and compete effectively over time.

Learn More
This is just one example of how analytical and palatability testing can help pet food product manufacturers make educated choices. Do you have questions or comments about pet food product shelf life and related testing? Post your thoughts here or email me at


Tags: stability, shelf life, pet food, palatant, palatability, oxidation, GCMS, flavor parameters, feline, ENT,