2. Product Stability & Shelf Life
Definition: The change in critical dependent variables as a function of
time. Critical variables include nutritional value, change in physical
state (e.g. colour) or change in sensory / organoleptic properties
(oxidation, off flavour) as a function of storage time under specified
storage conditions (temperature and % relative humidity).
What?
General Food Law: Microbiological Criteria and Labelling (‘date of
minimum durability’ which means the date until which a food retains
its specific properties when properly stored. ‘Use-by’ date or ‘Best-
before’ date).
Why?
Who? Responsibility: manufacturer, co-packers, re-packers, food caterers,
food retail outlets etc. depending on specific circumstances.
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3. Critical Dependent Variables
Nutritional / Chemical:
• loss of vitamins
• Loss of bioactivity
• Increase in anti-nutritional
factors.
Physical:
• Foam
• Gel
• Viscosity
• Emulsion
• Powder
Sensory:
• Colour
• Odour
• Texture / Mouthfeel
• Appearance
• Taste
4. Light Exposure
Temperature
Micro-organisms
Oxygen & Pressure
PRODUCT (Aw, formulation, pH, Ox/Red)
Parameters inducing changes to Product
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6. Decomposition
Product A
months
Values found
Regression Line
y = a + bx
y = Assay or amount of decomposition products
found [%]
x = Storage time [months]
a = y-Intercept at x=0
b = Slope of the line = degradation rate
Testing Data Prediction
7. Degradation at
Different
Temperatures
The reacton rate constantly
increases in an exponential manner
with the temperature:
•Generally reaction rates increase
as T increases.
•Chemical Reactions – vitamin loss
•Physical Reactions – diffusion,
sedimentation, phase transition (T
–Tg)
0 5 10 15 20 25 30 35
30
40
50
60
70
80
90
100
110
t [months]
Assay[%oflabelclaim]
2-8°C
25°C
40°C
- 0.23884
-1.8142
- 8.0571
11. 4
1
2
3
Applying a margin of
safety
Labelling of shelf-life
On-going monitoring and
verification
Confirm the samples to
be tested
Establish the study
duration
Establish the study
conditions
Establish the
frequency of testing
Establish the number
of samples to be
tested
Choose the testing
laboratory
What is involved in assigning shelf-life?
Establish the tests to
be performed
Perform and document
the durability study
Interpret the test
results and set the
shelf-life
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12. How can we help?
Assign Shelf-Life
Review stability data, predict changes of bioactives.
Evaluate reduced stability design (bracketing,
matrixing and bridging).
NOTE – No predictive framework for sensory stability. In-use must be evaluated throughout shelf life in real conditions.
Product Life Cycle
Review full supply chain to optimise shelf life
including shipping, transit, excursion,
distribution and in-house study.
Time dependent chemical reactions
Check contaminants from extractables where
product may interact with packaging over time.
Prepare Protocol
and execute on ambient and accelerated studies
to assign appropriate shelf-life. Make
recommendations to increase shelf life
(packaging and processing)
Compliance by Design
With targeted nutritional values to be within
regulatory limits to make specific claims to
maintain competitive advantage.
Identify minimum threshold values
for critical variables
Nutritional and chemical parameters, physical
and sensory properties