1、Designation: E 2454 05Standard Guide forSensory Evaluation Methods to Determine the SensoryShelf Life of Consumer Products1This standard is issued under the fixed designation E 2454; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision,
2、the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) 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 for establishi
3、ng 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 end-point. As suc
4、h, 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, executing, and interpre
5、ting 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 characteristics, performance
6、, 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 thetime at which a co
7、nsumer 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 used: (1)discri
8、mination, (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 develop predictive mo
9、dels 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 the shelf life
10、 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 research.1.5 T
11、his 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 life determina-t
12、ion.2. Referenced Documents2.1 ASTM Standards:2E 253 Terminology of Sensory Evaluation of Materials andProducts2.2 ASTM Manuals:3MNL 13 Descriptive Analysis TestingMNL 26 Sensory Testing MethodsMNL 30 Relating Consumer, Descriptive, and LaboratoryData to Better Understand Consumer Responses3. Termin
13、ology3.1 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 product.3.1.2 control parame
14、ters 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-eters (temperature, humid
15、ity, 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 of Materials and Products and is the direct responsibility of Subcom-mittee E18.05 on Sensory ApplicationsGeneral.Current edit
16、ion approved Nov. 15, 2005. Published November 2005.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Availabl
17、e 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 19428-2959, United States.attributes can be evaluated relative to these parameters. Forexample, controll
18、ed 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,discrimination, descriptive, or affective, or a combinationthereof).3.1.5 pull out date(s)predetermin
19、ed 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 human response to that product.3.1.7 shelf lifetime period that a product may be storedbefore reachi
20、ng 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. Thistesting is designed to manage distribution system risk.3.1.9 uncontrolled ambientalso known as roo
21、m 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).3.1.10 zero time pointtime when the shelf life testingbegins. It can be when the product is manuf
22、actured, 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 issues andpractical requirements of conducting a shelf life study designedto identify end points i
23、n 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 of elapsed time a product remains acceptable toconsumers,” or “determine specific use-by dates,” o
24、r “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 theselection of a specific end-point. Positive outcomes can bedefined as correctly estimating the time a
25、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 dissatisfiedand no longer purchase the product in the future. Another typeof negative outcome is to identif
26、y 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 balanced with theuse of testing resources, as a properly designed shelf life studycan use a lot of resou
27、rces.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 sensory profile has changed.4.4.2 A products attribute(s) (including off-notes) that is(are) known
28、 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 whichthe sensory attributes of the target product are required to remainunvarying and the extent to
29、 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 product. Selection of the method depends on chosenend-point criteria. For example, affective testing i
30、s 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 trained panelists. If consumer test methods areselected, then a sample of consumers must be drawn t
31、orepresent the population of potential consumers.4.7 Select Representative ProductsProducts selected forshelf life testing must be from representative productionbatches and production dates and appropriately processed andpackaged. In some situations, products should be subjected totypical distributi
32、on conditions (that is, vibration, temperatureelevation/reduction, temperature cycling, and so forth). Iftesting an experimental product (for example, changes iningredients, formulation, processing, or packaging), samplesshould be representative of production batches of the experi-mental product. Th
33、e 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-PointThe end-point is selectedbased on the chosen end-point criteria, the type of producttested, t
34、he 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 establishing the shelf life of a product. Thisinformation can also be used to assess the effects of n
35、ewtechnology, 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 aproducts sensory shelf life.5.3 Previous sensory research with similar products, mar-keting resear
36、ch, 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 determination criteria, andshelf life procedure should be reviewed and agreed to by thoseinvolved wit
37、h 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.Company policy/objectives, marketplace conditions, businessconsiderations, and risks all contribute to de
38、termining 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 affective testing methodsare the three major test method options.6.3 Clearly Determine the End PointTh
39、e 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 accept-ability to a predetermined level of acceptance The statisticalcriteria for measuring significa
40、nce 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 control product thatwill be used for the study:6.4.1 Option 1Stable ControlThis is a typical productthat
41、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 cannot be used. If discriminationtesting is the chosen method, this type of control is requiredbec
42、ause 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 descriptive analysis attribute ratingsor acceptance scores, depending on the chosen testing method.If
43、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 date. However, this type of control can only be used if thedifference between separate batches is de
44、monstrated 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 product is used, the testproducts should be obtained from the same batch as the controlproduct. If this
45、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 close in production as possible(that is, same production date, same product location, and soforth).
46、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 descriptive attributes, or acceptance, depend-ing on the chosen testing method.6.6 Determine Product Am
47、ount 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 berepresentative of the products in general should be stored underenvironmental conditions that represent the
48、 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 so forth).6.7.2 Extreme Storage ConditionsEstimates of environ-mental extremes and time spent in t
49、he 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 only approxi-mations of how a product may behave under normal storageconditions. During accelerated st
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