Significance and Use
5.1 Sensory shelf life is the time period during which the product’s sensory characteristics and performance are as intended by the manufacturer. The product is consumable or usable during this period, providing the end-user with the intended sensory characteristics, performance, and benefits. After this period, however, the product has characteristics or attributes that are not as intended, or it does not perform the same functions as fresh products or those consumed or used before the end of shelf life.
5.2 The goal of all shelf life determination is to estimate the time at which a consumer product is no longer usable, unfit for consumption, or no longer has the intended sensory characteristics.
5.3 Prior to the commencement of sensory shelf life study, the criteria/criterion that are/is used to define shelf life end must be defined. The criterion or criteria could be sensory attributes, consumer acceptance or product performance. Once the criteria are defined, the test methodology for measuring the sensory shelf life can be selected. The criterion operationally defining the end of shelf life is generally chosen based on one or more of the following changes in the product’s sensory or functional parameters, or both: (1) the aged product is perceptibly different from the fresh product overall, (2) the aged product has changed in specific sensory or functional attributes, either increasing some, decreasing others, or the appearance of new attributes compared to the fresh product, or (3) product acceptability of the aged product has decreased to a specific degree from that of the fresh product. The determination of these sensory end-points is a function of the criteria selected, the test method used, and sampling and statistical risks chosen by the researcher.
5.4 The three following test methods are most commonly used for the three end-point criteria cited above: (1) discrimination, (2) descriptive, and (3) affective. Researchers have to select criteria and methods that best suit the business risks associated with the selection of a final shelf life end-point.
5.5 Once a product is made, underlying chemical and physical processes continue: Time, temperature, oxygen, humidity, or light are some of the variables that can contribute to these chemical changes. The interaction of the product with the packaging may also impact the sensory shelf life of the product. These are often the independent variables included in a shelf life study. However, research techniques designed to identify the causes of sensory shelf life changes or to develop predictive models of shelf life are beyond the scope of this document.
5.6 Previous sensory research with similar products, marketing research, product technology, manufacturing considerations, marketing objectives, consumer comments, complaints, and other business criteria can all play a part in determining sensory end-point criteria.
5.7 The decision risk, end-point criteria, and shelf life testing procedure should be reviewed and agreed to by stakeholders, such as Marketing, Market Research, R&D, Quality Assurance, and Manufacturing.
Scope
1.1 This guide provides recommended sensory testing approaches and decision criteria for establishing the sensory shelf life of consumable products, including food, personal care, and household products, to manage business risk. It describes research considerations that include: product selection and handling, appropriate application of specific sensory test methods, selection of test intervals, and data analysis techniques for the determination of a product’s sensory shelf life end-point. This guide will focus on the practical considerations and approaches, risks, and criteria that must be considered in designing, executing, and interpreting sensory shelf life results.
1.2 This guide is not intended to provide a detailed description of how to conduct reliable sensory testing. It assumes knowledge of basic sensory and statistical analysis techniques, focusing instead on special considerations for the specific application of sensory testing methods to shelf life determination.
1.3 The shelf life measures in this guide refer to foods, household and personal care products stored as the manufacturer intended and do not account for changes in sensory properties occurring after opening, partial consumption/use or in-home storage. Once products have been manufactured, packaged and sent through the distribution channels, the condition of the products is not typically under study. However, a company may wish to include such variables in their shelf life studies when there is a need to evaluate the sensory quality of their products as they go through distribution channels or in-home storage, or both, and use.
1.4 This guide is not intended to address non-sensory issues related to the shelf life of food, including microbial contamination and chemical changes of products associated with aging, nor is it intended to address potential safety issues associated with aging food and non-food consumer products.
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
