1、Designation: E2454 05 (Reapproved 2011)Standard Guide forSensory Evaluation Methods to Determine the SensoryShelf Life of Consumer Products1This standard is issued under the fixed designation E2454; the number immediately following the designation indicates the year oforiginal adoption or, in the ca
2、se of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This guide provides appropriate sensory testing ap-proaches and possible decision criteria
3、 for establishing sensoryshelf life of consumer products. It describes research consid-erations including: product selection and handling, appropriateapplication of various sensory test methods, selection of testintervals, and data analysis techniques for the determination ofa products shelf life en
4、d-point. As such, this document coversshelf life studies designed to identify the sensory end-point ofa products life to manage business risk and meet businessneeds. This guide will focus on the practical considerations andapproaches, risks, and criteria that must be considered indesigning, executin
5、g, and interpreting shelf life results.1.2 Sensory shelf life is the time period during which theproducts sensory characteristics and performance are as in-tended by the manufacturer. The product is consumable orusable during this period, providing the end-user with theintended sensory characteristi
6、cs, performance, and benefits.After this period, however, the product has characteristics orattributes that are not as intended, or it does not perform thesame functions as fresh products or those selected before theend of shelf life.1.3 The goal of all shelf life determination is to estimate thetim
7、e at which a consumer product is no longer usable, unfit forconsumption, or no longer has the intended sensory character-istics. The determination of a sensory end-point is a function ofthe criteria selected, the test method used, and sampling risk.The three following test methods are most commonly
8、used: (1)discrimination, (2) descriptive, and (3) affective. Researchershave to select criteria and methods that best suit the businessrisks associated with the selection of a final shelf life end point.1.4 Research techniques designed to identify the causes ofsensory shelf life changes or to develo
9、p predictive models ofshelf life are beyond the scope of this document. These includethe application of regression analysis to develop statisticalmodels designed to predict sensory shelf life, studies thatassess the impact of various storage conditions, packagingmaterials, or product formulations on
10、 the shelf life of products,and studies designed to identify the causes of changes inproduct attributes over time. However, many of the researchmethods, experimental design considerations, and data analysistechniques discussed in this document can be applied to theseother types of shelf life-related
11、 research.1.5 This guide is not intended to provide a detailed descrip-tion of how to conduct reliable sensory testing. It assumesknowledge of basic sensory and statistical analysis techniques,focusing instead on special considerations for the specificapplication of sensory testing method to shelf l
12、ife determina-tion.2. Referenced Documents2.1 ASTM Standards:2E253 Terminology Relating to Sensory Evaluation of Ma-terials and Products2.2 ASTM Manuals:3MNL 13 Descriptive Analysis TestingMNL 26 Sensory Testing MethodsMNL 30 Relating Consumer, Descriptive, and LaboratoryData to Better Understand Co
13、nsumer Responses3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 accelerated storage/agingsubjecting a product toextreme or stressed conditions, such as elevated temperaturesor humidity, to create changes in product characteristics thatare assumed to be related to aging the pro
14、duct.3.1.2 control parameters for sensory shelf life determination(known as “control”)specific product or data set (based onprevious sensory research) designated as the one to which thedata from stored products are to be compared (see Section 6).3.1.3 controlled conditionsset of environmental param-
15、eters (temperature, humidity, light, oxygen, and so forth) thatare maintained and monitored so that changes in product1This guide is under the jurisdiction of ASTM Committee E18 on SensoryEvaluation and is the direct responsibility of Subcommittee E18.05 on SensoryApplications-General.Current editio
16、n approved Aug. 1, 2011. Published August 2011. Originallyapproved in 2005. Last previous edition approved in 2005 as E245405. DOI:10.1520/E2454-05R11.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStan
17、dards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from ASTM International Headquarters, 100 Barr Harbor Drive, POBox C700, West Conshohocken, PA 194282959.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428
18、-2959, United States.attributes can be evaluated relative to these parameters. Forexample, controlled ambient refers to maintaining a tempera-ture of 21 to 24C in storing the product.3.1.4 end pointpoint at which a product no longer meetspredetermined criteria as defined by test data (for example,di
19、scrimination, descriptive, or affective, or a combinationthereof).3.1.5 pull out date(s)predetermined point(s) in time atwhich the product is removed from storage for evaluation.3.1.6 sensory characteristicsany attributes of the prod-ucts that are assessed using the sensory methods that measurethe h
20、uman response to that product.3.1.7 shelf lifetime period that a product may be storedbefore reaching its end point.3.1.8 shelf life testingmethod(s) to determine the effectsof aging or storage conditions, or both, on product(s) charac-teristics for purposes of determining a products shelf life. Thi
21、stesting is designed to manage distribution system risk.3.1.9 uncontrolled ambientalso known as room tempera-ture, uncontrolled conditions (that is, temperature of storagelocation or environmental factors, or both) which fluctuate withchanges in weather, time of day, location, and so forth (see3.1.3
22、).3.1.10 zero time pointtime when the shelf life testingbegins. It can be when the product is manufactured, when theingredients equilibrate, when the product is put into storageconditions, or when the consumer is first likely to see it.4. Summary of Guide4.1 This guide is intended to cover the basic
23、 issues andpractical requirements of conducting a shelf life study designedto identify end points in a products shelf life.4.2 Define Research ObjectiveThe purpose of a shelf lifeproject should be clearly stated before the study is imple-mented. Common objectives are as follows: “determine theamount
24、 of elapsed time a product remains acceptable toconsumers,” or “determine specific use-by dates,” or “under-stand the amount of time elapsed before a sensory defect isdetectable.”4.3 Identify Decision RiskDecision risk is defined as thebalance of positive and negative outcomes associated with thesel
25、ection of a specific end-point. Positive outcomes can bedefined as correctly estimating the time a product remainswithin its intended sensory criteria. Negative outcomes can bedefined as leaving a product on the shelf after it is acceptable,thus increasing the chances that end-users will be dissatis
26、fiedand no longer purchase the product in the future. Another typeof negative outcome is to identify a too-early end-point, thusrequiring shelf removal of product that is still usable to theconsumer. Before the researcher embarks on a shelf life study,the risk to the consumer franchise must be balan
27、ced with theuse of testing resources, as a properly designed shelf life studycan use a lot of resources.4.4 Select Criteria to Determine the End-PointProductsdo change over time. End-point criteria can be one of thefollowing sensory analytical or consumer criteria, or both:4.4.1 The products overall
28、 sensory profile has changed.4.4.2 A products attribute(s) (including off-notes) that is(are) known or suspected to be key to the consumers percep-tion of the product has changed.4.4.3 Consumers consider the product no longer acceptable.NOTE 1Selection of end-point criteria depends on the extent to
29、whichthe sensory attributes of the target product are required to remainunvarying and the extent to which maintaining consumer acceptance isdeemed critical to the business.4.5 Select Sensory Test MethodDiscrimination, descrip-tive, or affective methods can be used to determine the shelflife of a pro
30、duct. Selection of the method depends on chosenend-point criteria. For example, affective testing is required ifa given consumer acceptance is the chosen end-point criterion.4.6 Define Representative AssessorsIf discrimination ordescriptive test methods are selected, the assessors used aretypically
31、trained panelists. If consumer test methods areselected, then a sample of consumers must be drawn torepresent the population of potential consumers.4.7 Select Representative ProductsProducts selected forshelf life testing must be from representative productionbatches and production dates and appropr
32、iately processed andpackaged. In some situations, products should be subjected totypical distribution conditions (that is, vibration, temperatureelevation/reduction, temperature cycling, and so forth). Iftesting an experimental product (for example, changes iningredients, formulation, processing, or
33、 packaging), samplesshould be representative of production batches of the experi-mental product. The amount of product required from eachproduction batch is dependent on the estimated length ofstorage, number of storage conditions, methods of evaluation,and frequency of testing.4.8 Determine the End
34、-PointThe end-point is selectedbased on the chosen end-point criteria, the type of producttested, the test method selected, previous knowledge of productchanges over time, and the companys business needs.5. Significance and Use5.1 Measuring product changes over time serves as apractical basis for es
35、tablishing the shelf life of a product. Thisinformation can also be used to assess the effects of newtechnology, processing, ingredients, packaging, and so forth,on the products shelf life.5.2 This guide provides a summary of the criteria to beconsidered and appropriate test methods for determining
36、aproducts sensory shelf life.5.3 Previous sensory research with similar products, mar-keting research, product technology, manufacturing consider-ations, marketing objectives, and other business criteria can allplay a part in determining sensory end point criteria.5.4 The decision risk, end-point de
37、termination criteria, andshelf life procedure should be reviewed and agreed to by thoseinvolved with the project, that is: R (2) a product attribute(s) that is known orsuspected to be key to the consumersperception of the producthas changed; and (3) the acceptability of the product is too low.Compan
38、y policy/objectives, marketplace conditions, businessconsiderations, and risks all contribute to determining the typeof shelf life end-point.6.2 Identify the Test Method to be UsedThis is done on thebasis of the chosen type of shelf life end-point criteria.Discrimination testing, descriptive, or aff
39、ective testing methodsare the three major test method options.6.3 Clearly Determine the End PointThe end point isestablished as either a significant overall difference from thecontrol or a significant change in the intensity of one or morecritical product attribute(s) or a significant decrease in ac
40、cept-ability to a predetermined level of acceptance The statisticalcriteria for measuring significance should also be included inthe end point definition (that is, a, b, and the effect size) alongwith the number of panelists needed at each testing interval.6.4 Select ControlChoose the type of contro
41、l product thatwill be used for the study:6.4.1 Option 1Stable ControlThis is a typical productthat is held under conditions that minimize changes over time,such as frozen or refrigerated storage or modified atmosphere.If no storage condition is known to keep changes to aminimum, this type of control
42、 cannot be used. If discriminationtesting is the chosen method, this type of control is requiredbecause it is needed to conduct the test at each pull out date.6.4.2 Option 2Statistical ControlThis is a set of nu-merical values obtained from sensory testing at zero time.Sensory data can be either des
43、criptive analysis attribute ratingsor acceptance scores, depending on the chosen testing method.If discrimination testing is the chosen method, this type ofcontrol cannot be used.6.4.3 Option 3Fresh ControlIf none of the above con-trols are feasible, a fresh control may be obtained at each pullout d
44、ate. However, this type of control can only be used if thedifference between separate batches is demonstrated to beminimal prior to the study.6.5 Select Test ProductChoose the test product(s) for thestudy. The product used for the study should be representativeof intended product. If a control produ
45、ct is used, the testproducts should be obtained from the same batch as the controlproduct. If this is not feasible, various batches can be used withthe added risk of variability that may obscure the differencesbetween the control and test product. However, the test andcontrol products should be as c
46、lose in production as possible(that is, same production date, same product location, and soforth). Furthermore, at the start of the storage period, an initialsensory test should be conducted to ensure that the test andcontrol products are in fact not different in either overallprofile, specific desc
47、riptive attributes, or acceptance, depend-ing on the chosen testing method.6.6 Determine Product Amount Needed to Conduct the Testfor each Evaluation PointCalculate the amount of productneeded for each test.6.7 Select Storage Conditions:6.7.1 Typical Storage ConditionsProducts selected to berepresen
48、tative of the products in general should be stored underenvironmental conditions that represent the typical productdistribution channel, and may include variations in tempera-ture, humidity, light, atmosphere, air pressure, and environ-mental cycling (freeze/thaw, elevated temperature conditions,and
49、 so forth).6.7.2 Extreme Storage ConditionsEstimates of environ-mental extremes and time spent in the various stages ofdistribution can help determine appropriate conditions. Verifi-cation of test storage conditions through the use of sensors ormonitors is suggested, especially if ambient storage conditionsare selected.6.7.3 Accelerated Storage ConditionsAccelerated testsattempt to achieve changes in product characteristics in a shortperiod of time. Such tests can be valuable time savers ifappropriately selected. However, these tests are o
