the handbook of food engineering practice crc press chapter 10 ...

10.3 APPLICATION OF FOOD KINETICS IN SHELF LIFE PREDICTION AND
CONTROL
10.3.1.Accelerated Shelf Life Testing
Taking into account the described limitations and the possible sources of deviation, the
Arrhenius equation can be used to model food degradation for a range of temperatures.
This model can be used to predict reaction rates and shelf life of the food at any
temperature within the range, without actual testing. Equally important it allows the use of
the concept of accelerated shelf life testing (ASLT).
ASLT involves the use of higher testing temperatures in food quality loss and
shelf life experiments and extrapolation of the results to regular storage conditions through
the use of the Arrhenius equation. That cuts down very substantially the testing time. A
reaction of an average E A of 90 kJ/mol may be accelerated by 9 to 13 times with a 20°C
increase in the testing temperature, depending on the temperature zone. Thus an
experiment that would take a year can be completed in about a month. This principle and
the methodology in conducting effective ASLT are described by Labuza (1985), Labuza
and Schmidl (1985), and in a publication by the Institute of Food Science and Technology,
UK (IFST,1993).
Designing a shelf life test is a synthetic approach that requires sufficient
understanding of all food related disciplines, namely food engineering food chemistry,
food microbiology, analytical chemistry, physical chemistry, polymer science and food
regulations. The following steps outline the ASLT procedure:
1. Evaluate the microbiological safety factors for the proposed food product and
process. Use of the Hazard Analysis Critical Control Point (HACCP) principles is a good
approach to be followed from the design stage. If major potential problems exist at this
47