According to the Institute of Food Technologists (IFT) and the National Advisory Committee on Microbiological Criteria for Foods (NACMCF), shelf-life is “the amount of time that a food product is considered acceptable for consumption when stored at the appropriate storage conditions.” When determining if a food product is acceptable for consumption, several factors – including organoleptic properties (taste, texture, odor, appearance), microbial spoilage and chemical changes to the product during storage – must be considered.
What is an Accelerated Shelf Life Study?
Shelf-life studies can come in many different forms, including accelerated studies. In these studies, accelerated conditions (i.e. elevated temperature) are applied to eligible products to predict product shelf-life at typical storage conditions. This process is performed using the Q10 value. The Q10 value of a product is the temperature quotient for a 10°C temperature difference, as expressed in the equation below:
Typically, a Q10 value of 2 is used as an initial shelf-life estimate, but this may not represent the actual acceleration factor of a specific food product. It is recommended that accelerated shelf-life studies be accompanied by a shelf-life study conducted under normal storage conditions in order to determine the actual Q10 value. This approach allows for a more specific Q10 value and can be used for future accelerated shelf life studies on similar products.
The most prominent spoilage concern for products eligible for accelerated shelf-life studies is rancidity. Rancidity is a chemical change in the product that occurs in a number of ways, depending on ingredients and packaging. Common forms of rancidity include:
- Hydrolytic Rancidity – Hydrolysis of triglycerides into fatty acids and glycerol, resulting in a distinctive “soapy” flavor when the product has spoiled
- Oxidative Rancidity – Lipid oxidation of unsaturated fatty acids into hydroperoxides, which later form aldehydes, causing a distinctive “cardboard” flavor/aroma when the product has spoiled
Is an Accelerated Shelf Life Study Right for Your Product?
Shelf stable and frozen products with a shelf-life of six months or more are good candidates for accelerated shelf life studies. Accelerated shelf life studies are not recommended for all products, such as refrigerated products that spoil due to microbial growth. Each product has a specific mode of spoilage (i.e. rancidity, moisture loss/gain, organoleptic changes), so every study is tailored to the specific product.
Mérieux NutriSciences scientists work extensively with clients to design meaningful and robust studies based on individual product characteristics and product history.