18 Dec 2020

The Science Behind "Sell by" Dates

The concept of a shelf life is found in many industries: cosmetics, pharmaceuticals, batteries and, perhaps most commonly in food and beverages. Shelf life refers to the length of time a product may be stored before they become unfit for use, consumption, or sale. In the food industry it can apply to both fresh foods, such as produce or dairy products, as well as "pantry" items like canned goods, cereal, crackers, pasta and more. 

Shelf life is concerned with degradation of a product due to physical, microbiological, and chemical processes. It begins as soon as a product is manufactured and packaged. Degradation can be triggered by any one of a multitude of contributing factors: light, heat, temperature, moisture content, acidity levels, quality/consistency of ingredients, storage, transport, and packaging. In some cases, shelf life can be extended by using preservatives, preservation processes and techniques like modified atmosphere packing.

Food shelf life considerations are important because degraded products can have multiple negative consequences.  Some of these are simply inconveniences: loss of taste, staleness, or texture issues.  However, there are health and safety concerns related to shelf life, particularly with food that has spoiled or become rancid.  For example, bacterial colonies may develop and grow, leading to food poisoning. Because of the potential outcomes that can arise related to expired products, government regulatory agencies and retailers have requirements in place related to food shelf life.

Because degradation in a product can impact both its quality and safety, and given the various requirements in place, food manufacturers need to determine "use by" or "best before" dates as accurately as possible.  This will not only ensure compliance to any requirements, but also help safeguard the reputation of the brand, keep consumers safe and meet customer expectations.  

Food shelf life testing and analysis uses a combination of analytical, microbiological and sensory evaluations to assess how a product ages and degrades and then uses that information to identify accurate "sell by," "best before" or expiration dates. Given the complexity of factors contributing to the shelf life of food, it is important to develop and carry out a customized assessment program that is tailored specifically to the product, its ingredients and preparation, storage, and packaging.

A thorough testing program might include tests for:

  • Foodborne microorganisms such as:
    • Listeria
    • Salmonella
    • E. Coli
    • Staphylococcus Aureus
    • Bacillus Cereus
    • Lactic Acid Bacteria
    • Yeasts
    • Molds
  • Total viable count
  • Enterobacteriaceae
  • Moisture content
  • Acidity levels
  • ph
  • Water activity
  • Fat rancidity
  • Sensory analysis

Make sure you are familiar with the requirements in place for your food product, given its type and the market you are selling in.  It is also important to know details on the ingredients, packaging, storage and transportation of the product, as these will all impact degradation and need to be considered in the assessment.  Work with a trusted partner who knows the requirements and can effectively, thoroughly run evaluations to best inform your decisions. Food shelf life is important for safety but also reputation in the marketplace. It is an essential step in the product development process.


Kenneth Cote,
Director of Agriculture and Food


Kenneth Cote has been in the agricultural industry for more than 15 years, starting his career as a barge sampler and advancing to his current leadership role.  He has worked with multiple cargos and situations around the world.  Ken utilizes his experience working within the agricultural, fertilizers, foods, dietary supplements, metals, minerals, solid fuels, plastics, chemicals, veg oils and regulatory compliance industries to add value to our customers.

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