Carole's section
I'm Carol Bingley, Product and Ingredient Innovation Technical Specialist at RSSL. Today, myself and Rob Griffiths, our Lipids Technical Specialist, will be discussing shelf life and the vital role that this plays in new product development process.
Determination of shelf life of the food product is a critical part of the product development process. It is necessary to state a 'use buy' or 'best before' date on your packaging and getting it right is important to both minimise consumer complaints, but at the same time maximise the potential time between manufacture and sale of the product. The shelf life of a product may be determined by growth of microorganisms, resulting in the food product no longer being safe to consume, or by changes in the taste and texture which mean that although the product does not pose a food safety risk it is no longer acceptable to the consumer. Additionally, if a nutritional claim is being made on a product, then it is necessary to be able to prove that levels of that nutrient meet requirements for the claim throughout shelf life. In terms of product development, shelf life is impacted by ingredient selection and quality, ph, water activity, processing and packaging.
If we think about ingredient selection, there are a few food industry trends which are restricting the number of ingredients which can be used to help attain shelf life. One is the move to shorter ingredient lists, removal of additives including preservatives, and also the use of recyclable packaging. Nutritional drivers for reformulation, such as reduction in saturated fat, sugar and / or salt, also provide challenges to the product developer when thinking of shelf life. For example, changing to a more highly unsaturated fat can result in an increased likelihood of rancidity, whereas sugar and salt both help manage water activity and hence microbial growth.
Shelf life needs to be considered right from the start of the product development process, including ensuring that you select ingredients which provide the required quality, and adjusting the formulation to meet ph and water activity of targets. Some shelf life testing can be carried out during the development process to help screen different ingredients, but we would always recommend that full shelf life testing is carried out on the finished product, manufactured on the production line that will be used for launch, and packed into final packaging.
Rob's section
As Carol mentioned the shelf life should be considered early in product development and we always advise to get the RSSL team involved as soon as possible since we can highlight some of the changes that might occur during shelf life, and the factors that affect them, and suggest ways to mitigate them. During development of food products, there might be several prototypes to compare, and it would be time consuming to evaluate all of these for shelf life. This is where instruments that can accelerate the deterioration of products can be really useful.
They can be used to rapidly compare the relative stability of different samples and give very approximate guidance on the shelf life so the best option is taken forward for full shelf life studies. For example, we have instruments that can accelerate the oxidation and rancidity development, and other instruments that can accelerate and monitor emulsion breakdown and moisture changes. Once a new product has been optimised we would always recommend carrying out full shelf life storage study, to gain the most accurate evaluation of the shelf life, and we can also provide support in the design of these studies. They generally involve storing products at the specified conditions and carrying out sensory and / or analytical tests over time.
Sensory evaluation is generally the ultimate gauge of a product's performance, since this most closely reflects the consumer's experience. However, analytical testing can be particularly useful since changes can sometimes be detected sooner during shelf life and can be an early warning of product deterioration. These storage studies can be quite time consuming, but these can also be accelerated in some situations, which will shorten the study time to get earlier results. So, to sum up, the testing of quality of ingredients, the adjustment of formulation for parameters such as ph and water activity, and the use of accelerated studies, are all ways to optimise product stability and shelf life. This should hopefully reduce the time taken for development and a quicker route to market for your products.