Purposes and Principles of Shelf Life Determination

Although it may seem simple, setting the shelf life of perishable food products is a complex undertaking involving food safety and quality factors impacted by distribution and storage conditions. Even for food products that have a long history of production, distribution, sale, and consumption (e.g., fresh meat, pasteurized milk, fresh produce), there are frequent modifications and variations to the products, production process, packaging, and the means of distribution and display. Consumer preferences and lifestyles have impacted food product formulation, preparation, and consumption habits, and this too provides the impetus for renewed focus on shelf life determination. Various stakeholders concerned with shelf life of food products include food processors, distributors, customers, regulators, and consumers. Differing perspectives of these stakeholders coupled with the subjectivity of food quality, result in a changing value designation to perishable foods throughout shelf life. Therefore, the methods and criteria for shelf life acceptance have a considerable bearing on business. The procedures used to determine shelf life depend upon multiple factors, principally the food type and temperature. The increasing sophistication of laboratory methods for analysis means that the shelf life termination metrics are also constantly changing. Shelf life determination of novel products or traditional products produced in novel ways can require elaborate studies during the development phase. Upon commercialization, shelf life tests must be performed upon the first several lots of production in order to verify previously determined outcomes with prototypical samples. In some instances, challenge studies must be performed to validate the ongoing safety throughout shelf life. Then for ongoing food production, routine shelf life testing is an essential quality metric, albeit a lagging indicator of quality. Attributes measured include microbiological counts, chemical degradation, physical deterioration, and sensory properties. For perishable foods, the microbiological attributes are usually the primary metric, and often the most limiting factor. Shelf life testing procedures must generate data that clearly define the amount of time a product has a useable wholesome state under the expected conditions of storage using agreed upon methods and acceptance criteria.