Stability Testing in animal feed consists of several primary factors considered in the development of premix products bioavailability, uniform distribution of active ingredients within the product, and optimal handling and mixing characteristics such as high flowability, low dustiness, low hygroscopicity and absence of caking and minimal segregation. These characteristics are especially important with vitamins because these essential nutrients are added in reasonably small amounts to premixes as well as other functioning APIs (Active Pharmaceutical Ingredient). The presence or absence as well as the wrong concentration of APIs in specific batches can affect the animal’s overall performance in terms of growth, health, and deliverability i.e. production.

Premix Stability Testing
Additives in animal feed should be distributed homogeneously. This is mainly realized by the use of a premix with a high concentration of active ingredients. Premixes consist of excipients with one or more active ingredients as trace elements, vitamins, nutrients, amino acids, medical additives, and so on. To ensure continuous high activity and to avoid degradation, rigid conditions for their storage are generally necessary. Depending on the components a premix can be sensitive to environmental factors such as temperature, humidity, oxidation, light, shear but also the overall composition with metal elements, and oxidation or reducing components.

Storage conditions
Premix composition affects vitamin stability, especially with regard to the presence or absence of various compounds such as inorganic trace minerals. These compounds are reactive with vitamins and reduce their stability. Similarly, the processes used in feed conditioning and manufacturing affect vitamin activity. Pelleting as well as extrusion reduce vitamin activity in proportion to the amount of heat and pressure applied to the feed during processing. Often, the net stability of vitamins in feeds or premixes is affected by two or more major factors, including the time of storage, e.g. the stability of vitamin A (one of the least stable vitamins) is strongly affected by both product form and storage conditions. Evidence is necessary to demonstrate the stability of the premix before incorporation into a feed end product. The shelf-life specification of a premix includes stability indicating test parameters. The thermal stability and sensitivity is evaluated under storage conditions, long term covers a minimum of 12 months up to 5 years, intermediate covers a 12 months study and accelerated a 6 months study. The appropriate temperatures are 25 °C, 30 °C or 40 °C with RH of 60%, 65% or 75% in accordance with the international standards. Divergent storage conditions during handling but especially during shipping will be tested at appropriate temperatures and relative humidity. The testing is carried out in the final packaging proposed for marketing when practicable. The use of small comparable containers or bags simulating the actual market packaging are in most cases justified.

Testing Frequency
In general, the testing intervals are sufficient to establish the stability of the product, including the initial and final time points the tests are performed every 3 months and can be reduced in the 2nd year to 6 months, and thereafter annually.

Testing Procedures
Testing procedures cover the features susceptible to change during storage and likely affects the quality of the product. On the whole, there is no single stability-indicating assay or parameter that profiles the stability characteristics of a product. In consultation with the applicant a stability-indicating profile will be attuned.

Stability-indicating test methods are applied and cover chemical, biochemical and physical methods.

Chemical

  • (trace) Elements, by Neutron
  • Activation and X-Ray Fluorescence

Biochemical

  • Vitamins
  • Nutrients

Physical

  • Dustiness

Flowability

  • Particle size distribution
  • Specific surface area

Our expertise
Delft Solids Solutions adheres to the international standards (ASTM, ISO, EPA OPPT etc.) in regards to the various analyses on various levels.

Additional analytical procedures, such as microscopy (optical or SEM), visual appearance of the product, pH, moisture level, water adsorption, caking, density, pore volume, segregation etcetera are possible. The tested products in bags or generated dust from the product can also be returned to the applicant for “in-house” testing.

About the DSS Method
Investigations are performed in close consultation with the client and – as far as possible – executed under conditions that closely match the targeted application of the product or actual problem. This is feasible due to the broad array of instruments and specially designed and built setups, accessories, and sample holders, and access to a modern workshop enabling the design of additional accessories.

Stability Study
– In accordance with the International Cooperation on Harmonization of Technical Requirements for Registration of Veterinary Medicinal Products.

– In collaboration with the applicant a premix or product of active ingredients and excipients for the animal group and age targeted is composed, homogenized and divided into representative lots for controlled storage testing and subsequently physical, biochemical and or chemical assay.

– The API manufacturing industry has developed products of extraordinary purity and quality, with improved stability, high bio-availability and optimal handling and mixing properties. Today’s vitamin product forms have marked advantages over the raw vitamin forms when used in feed or food manufacturing. However, when dealing with complex and reactive compounds such as vitamins, no product form can offer complete and unlimited protection against destructive conditions, excessive periods of storage or severe manufacturing processes.

– The individual feed manufacturer is therefore responsible in assuring customers that the APIs have been stored, handled and added to the end product in under ideal conditions and manners. Offering a guarantee that APIs are routinely monitored for quality assurance.

– “Significant change” at the accelerated condition is defined as a failure to meet specifications. Out of spec results are reported directly when established at a test interval. – Finally the stability is reported in accordance with time and humidity storage and statistically evaluated.