At dicentra, we get many requests for assistance with new product development and formulation changes. Developing a new product or adjusting a formulation can be one of the most satisfying endeavors in the food industry as you watch your product blossom from a tabletop concept into a household staple. There are many factors to consider during the product development process, like market analysis and consumer evaluation. However, the most important step in the process is knowing what your food product’s shelf life or durable life is. You may have seen the outcome of shelf-life testing and determination in play across grocery aisles in the form of best before dates, use-by dates, and expiry dates.

Food businesses are responsible for complying with the law. They demonstrate compliance by ensuring that the commodities and processes for which they are responsible meet regulatory requirements. Shelf-life studies help establish how long a food, under the conditions it is normally handled and stored, can retain the desired palatability and quality, remain wholesome, meet nutritional declarations, and preserve its microbial, chemical and physical integrity.

Shelf-Life Testing Methods

The shelf life of food can be affected by a variety of intrinsic factors that relate to the product itself and extrinsic factors that relate to external conditions. The methods used for conducting shelf-life studies will depend on the size and complexity of the business, however, there are many basic factors that each shelf life evaluation will consider. The first consideration is the challenge study method which will be undertaken; will you do a real-time study or an indirect, accelerated study? With a real-time shelf life study, the food is stored under normal conditions for a period greater than the estimated shelf life. The state of the food is verified at regular intervals to determine the point at which it deteriorates and no longer has the quality, nutritional value, or microbial, chemical and physical integrity it should have. With an indirect shelf life study, the shelf life of food is predicted using accelerated factors such as increased temperatures and exposure to light to increase the rate of deterioration. The data obtained when measuring the accelerated rate of deterioration, such as data on microbial load, can be used in a predictive model or software to determine what the spoilage rate and bacterial growth would be under normal conditions. Typically, accelerated studies are done when the shelf life of a product is long and falls outside the facility’s product development schedule.

Finding Your Best Before Date

1. Before beginning either type of study, you will want to determine the projected shelf life. This is typically done through a review of scientific journals, industry guides, and other publications to establish the shelf life of the food. Some facilities may have similar products or product lines and will be able to estimate a similar shelf life for the new/changed product. Another consideration is to look at the retail level itself and examine the shelf life of similar products if they exist.
2. The next step is determining the properties of your product that may be at risk of deterioration. Intrinsic properties that may be considered are ingredient quality, the composition of the final product (how the ingredients interact), any preservatives added, and characteristics of the product such as the water activity or pH level. Extrinsic Properties of consideration would include processing conditions (HPP, cooking, cooling, etc.), packaging conditions (vacuum packaging, oxygen permeable packaging, etc.), storage conditions (cooler, freezer, dry/wet, etc.), distribution chain factors, and finally, consumer practices.
3. Next, you determine what your indicators for end of durable life are. You do this in a two-fold manner: one is through sensory evaluation, and the other is through chemical and microbiological evaluation. Microbiological and chemical evaluations are used to evaluate both the safety and quality of the food product. Microbiological tests are done to evaluate growth and change in spoilage organisms over time or to evaluate the level a foodborne pathogen can reach if it were to become present in the food (typically through a challenge study, which is the worst-case scenario). Chemical tests can detect changes in quality throughout the shelf life such as pH, headspace, free fatty acids, etc. For sensory evaluation, you will determine what your important product characteristics are (certain color, a certain smell, a certain taste, etc.) and evaluate how they respond over the stated shelf life. Even if you determine that your product is microbiologically and chemically safe, you still may want to allow these quality characteristics to have an impact in determining your shelf life as they will impact your customer response.
4. Once you have considered all these factors, the next step is to plan out your study and determine sample collection methods, the number of samples, frequency of evaluation and other such factors that will be required to properly evaluate your product. Once you’ve planned out your durability test, you will conduct the test and then evaluate the data to determine the actual shelf life of the food. A point will be reached, sometime during the sampling and testing period of the shelf life study, when the food no longer meets safety, nutritional or quality standards. The shelf life of a food is based on the minimum amount of time it takes for the product to fail any one of the qualifying criteria, regardless of whether it relates to quality or safety. 
5. You’ve finally come to the critical part of shelf-life testing: declaring the shelf life and using it to create a best before date. The best practice is for the declared shelf life to be the actual shelf life with the inclusion of a safety margin. The safety margin is based on your evaluation of tests results and should give a space for reassurance that under consumer control, the product will still be safe to consumers and meet quality standards at the stated best before date.

Are you having difficulties with shelf life testing, or in any area of food safety & quality? Reach out to us for further assistance and we’ll get you on your way to achieving your next set of food business goals.

dicentra provides sought-after guidance on product and marketing compliance, quality assurance and safety standards, research and development, new ingredient assessments and overall regulatory strategies for food and health-related products sold in North American marketplaces. We can be reached at 1-866-647-3279 or info@dicentra.com.