1、Designation:F141696(Reapproved 2014)Standard Guide forSelection of Time-Temperature Indicators1This standard is issued under the fixed designation F1416;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A numb
2、er 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 covers information on the selection ofcommercially available time-temperature indicators(TTIs)fornoninvasive external package use on
3、 perishable products,suchas food and pharmaceuticals.When attached to the package ofa perishable product,TTIs are used to measure the combinedtime and temperature history of the product in order to predictthe remaining shelf life of the product or to signal the end of itsusable shelf life.It is the
4、responsibility of the processor of theperishable product to determine the shelf life of a product at theappropriate temperatures and to consult with the indicatormanufacturer to select the available indicator which mostclosely matches the quality of the product as a function of timeand temperature.N
5、OTE1Besides time-temperature indicator,TTI is also an abbrevia-tion for time-temperature monitor and time-temperature integrator.1.2 Time-temperature indicators may be integrated into aHazard Analysis and Critical Control Point(HACCP)plan.Appropriate instructions should be established for handlingpr
6、oducts for which either the indicator has signaled the end ofusable shelf life or the shelf life of the product at its normalstorage temperature has been reached.1.3 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user
7、 of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Terminology2.1 Definitions:2.1.1 activation energythe quantity commonly used todescribe the dependence of the shelf life of a product(or therate of a reac
8、tion)on temperature,as given by the Arrheniusrelationship.2.1.1.1 DiscussionThe higher the activation energy,themore the shelf life of a product changes with temperature.Ifthe shelf life of a product is known at two temperatures,theactivation energy is given by the following formula:Ea5lnLIFE1/LIFE2
9、!1T121T23R(1)where LIFE1and LIFE2=shelf lives at temperaturesT1and T2.2.1.2 all-temperature time-temperature indicator a TTIthat continues to change at some rate at all temperatures.2.1.3 Arrhenius plota plot of the logarithm of the shelf lifeof a product versus the reciprocal of temperature(1T).2.1
10、.3.1 DiscussionIf the shelf life of a product exhibitsArrhenius behavior,then anArrhenius plot of the shelf life willbe a straight line.The activation energy of the shelf life is equalto the slope of the line times R(see 2.1.1.1).It is more accurateto use a regression analysis to determine the slope
11、 based on thedata from at least three temperatures than to use only twopoints as in the previous equation.A blank Arrhenius plot isshown in Fig.1.The plot axes are the log10of the shelf life andthe reciprocal of temperature.For ease of use,the Fahrenheitand Celsius temperatures are shown on the grap
12、h instead of theinverse temperature.2.1.4 Arrhenius relationshipa relationship that describesthe dependence of the rate of a chemical reaction on tempera-ture as follows:k 5 A0e 2SEaRTD(2)where:k=rate constant,A0=constant with the same time units as k,T=temperature,K(C+273),andR=universal gas consta
13、nt.When R=0.001987 kcal/(mol deg),the activation energy,Ea,is given in units of kcal/mol.When R=0.00831 kJ/(mol deg),the activation energy,Ea,is given in units of kJ/mol.2.1.4.1 DiscussionThis relationship also describes the de-pendence of the shelf life of many TTIs and perishableproducts on the ef
14、fective average temperature to which they areexposed.Since the shelf life is the time for the reaction to1This guide is under the jurisdiction of ASTM Committee F02 on FlexibleBarrier Packaging and is the direct responsibility of Subcommittee F02.15 onChemical/Safety Properties.Current edition appro
15、ved April 1,2014.Published April 2014.Originallyapproved in 1996.Last previous edition approved in 2008 as F1416 96(2008).DOI:10.1520/F1416-96R14.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 proceed to a specific extent,theArrhenius re
16、lationship for shelflife is given by the following formula:LIFE5 BeSEaRTD(3)where B=constant with the same time units as LIFE.2.1.5 dual function time-temperature indicator a TTI thatcombines both all-temperature and threshold-temperatureresponses,overlaid in a single indicator in order to modify thetotal time-temperature response.2.1.6 effective average temperaturethe single constanttemperature that would have the same effect on the shelf life ofa product as the actual temperature profile has f