Real Time vs. Accelerated Shelf Life Studies
There are two basic methods for performing shelf life studies:
Real Time and Accelerated. Real time studies store the product
under the normal conditions of the product for a period of
time greater than the expected shelf life. The product is
checked at regular intervals to determine the point of product
deterioration.
Accelerated shelf life studies attempt to predict the shelf
life of a product without running a full length storage trial.
This type of study is usually used for product with a longer
shelf life. Acceleration factors such as temperature are applied
to the product to attempt to increase the rate of deterioration.
The data can be used in predictive mathematical models to
project spoilage rates and bacterial growth. Accelerated studies
should be used with caution, you must know a good deal about
your specific product formulation and properties to interpret
the data optimally.
It is always recommended that when an Accelerated study is
selected that a dual, real-time study is also run concurrently
to validate the projected data.
7 Steps to Determine Shelf Life
- Identify what may cause the food to spoil
- Product: raw materials, formulation, water activity, pH,
oxygen availability, preservatives
- Process: Processing activities, packaging, storage conditions
- Decide which tests to use
- Sensory: odor, appearance, flavor texture
- Microbiological: spoilage and pathogenic organisms
- Chemical: pH, free fatty acids, headspace analysis, etc.
- Physical: product abuse storage and handling
- Plan the shelf-life requirements
- What tests need to be done
- How long will the studies be run
- How many samples for each test
- How many samples for the entire study
- What are the storage conditions
- When will the study be run
- Run the Shelf Life study
- At time intervals established in step 3.
- Run the appropriate tests in step 2
- Determine the shelf life
- Eventually a point is reached when the product no longer
meets requirements for quality or safety, which is the shelf
life
- Usually a pre determined point is established to end the
study if quality and safety are not affected
- Establish working shelf life
- Working shelf life will be less than actual shelf life
due to real world factors such as storage conditions and potential
product abuse
- Once product is released to the market -> Monitor Shelf
Life
- Investigate any customer complaints or failures
- Evaluate samples from production and distribution to validate
study results
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