ASTM F1416-96(2019)
(Guide)Standard Guide for Selection of Time-Temperature Indicators
Standard Guide for Selection of Time-Temperature Indicators
SIGNIFICANCE AND USE
3.1 Expiration dates are often marked on the packages of perishable products to indicate the presumed end of their shelf lives. Since the shelf lives of most perishable products are temperature dependent, the expiration date is determined by assuming the product will be kept within a prescribed temperature range for its entire life. A problem with this method is that there is no way to determine if the shelf life of a product has been shortened by exposure to a higher temperature. A time-temperature indicator solves this problem when attached to the package because it reaches its end point sooner when exposed to a higher temperature.
3.2 In order to directly indicate the end of the shelf life, the time-temperature indicator characteristics should be matched as closely as possible to the quality characteristics of the product. When kept at the standard storage temperature for the product, the indicator should reach its end point at the same time as the product's shelf life. In addition, to determine the accuracy of the match at other temperatures, the change of shelf life with temperature should be known for both the product and the indicator. The Arrhenius relationship is a common and convenient method of describing the change of shelf life with temperature. In cases where it is not applicable, individual time-temperature points for the product may be established and an approximate correlation with the TTI obtained.
3.3 When attached to the package of a perishable product, a time-temperature indicator may supplement, or in some cases replace, the expiration date code. The addition of a TTI provides a greater level of confidence that the perishable product is within its shelf life because it responds to the actual temperature conditions to which the product has been exposed.
3.4 In the case of minimally processed refrigerated foods, the rapid growth of pathogenic bacteria at elevated temperatures may pose a serious health hazard even before the deterioration...
SCOPE
1.1 This guide covers information on the selection of commercially available time-temperature indicators (TTIs) for noninvasive external package use on perishable products, such as food and pharmaceuticals. When attached to the package of a perishable product, TTIs are used to measure the combined time and temperature history of the product in order to predict the remaining shelf life of the product or to signal the end of its usable shelf life. It is the responsibility of the processor of the perishable product to determine the shelf life of a product at the appropriate temperatures and to consult with the indicator manufacturer to select the available indicator which most closely matches the quality of the product as a function of time and temperature.
Note 1: Besides time-temperature indicator, TTI is also an abbreviation for time-temperature monitor and time-temperature integrator.
1.2 Time-temperature indicators may be integrated into a Hazard Analysis and Critical Control Point (HACCP) plan. Appropriate instructions should be established for handling products for which either the indicator has signaled the end of usable shelf life or the shelf life of the product at its normal storage temperature has been reached.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.4 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.
General Information
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Standards Content (Sample)
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.
Designation: F1416 − 96 (Reapproved 2019)
Standard Guide for
Selection of Time-Temperature Indicators
This standard is issued under the fixed designation F1416; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2.1.1 activation energy—the quantity commonly used to
describe the dependence of the shelf life of a product (or the
1.1 This guide covers information on the selection of
rate of a reaction) on temperature, as given by the Arrhenius
commercially available time-temperature indicators (TTIs) for
relationship.
noninvasive external package use on perishable products, such
2.1.1.1 Discussion—The higher the activation energy, the
as food and pharmaceuticals. When attached to the package of
more the shelf life of a product changes with temperature. If
a perishable product, TTIs are used to measure the combined
the shelf life of a product is known at two temperatures, the
time and temperature history of the product in order to predict
activation energy is given by the following formula:
the remaining shelf life of the product or to signal the end of its
usable shelf life. It is the responsibility of the processor of the
ln LIFE /LIFE
~ !
1 2
E 5 3R (1)
perishableproducttodeterminetheshelflifeofaproductatthe
a
1 1
appropriate temperatures and to consult with the indicator
T T
1 2
manufacturer to select the available indicator which most
where LIFE and LIFE = shelf lives at temperatures
closely matches the quality of the product as a function of time 1 2
T and T .
and temperature. 1 2
2.1.2 all-temperature time-temperature indicator— a TTI
NOTE 1—Besides time-temperature indicator, TTI is also an abbrevia-
tion for time-temperature monitor and time-temperature integrator.
that continues to change at some rate at all temperatures.
1.2 Time-temperature indicators may be integrated into a
2.1.3 Arrhenius plot—aplotofthelogarithmoftheshelflife
Hazard Analysis and Critical Control Point (HACCP) plan.
of a product versus the reciprocal of temperature (1\T).
Appropriate instructions should be established for handling
2.1.3.1 Discussion—If the shelf life of a product exhibits
products for which either the indicator has signaled the end of
Arrhenius behavior, then anArrhenius plot of the shelf life will
usable shelf life or the shelf life of the product at its normal
beastraightline.Theactivationenergyoftheshelflifeisequal
storage temperature has been reached.
to the slope of the line times R (see 2.1.1.1). It is more accurate
1.3 This standard does not purport to address all of the
to use a regression analysis to determine the slope based on the
safety concerns, if any, associated with its use. It is the
data from at least three temperatures than to use only two
responsibility of the user of this standard to establish appro-
points as in the previous equation. A blank Arrhenius plot is
priate safety, health, and environmental practices and deter-
shown in Fig. 1.The plot axes are the log of the shelf life and
mine the applicability of regulatory limitations prior to use.
the reciprocal of temperature. For ease of use, the Fahrenheit
1.4 This international standard was developed in accor-
and Celsius temperatures are shown on the graph instead of the
dance with internationally recognized principles on standard-
inverse temperature.
ization established in the Decision on Principles for the
2.1.4 Arrhenius relationship—a relationship that describes
Development of International Standards, Guides and Recom-
the dependence of the rate of a chemical reaction on tempera-
mendations issued by the World Trade Organization Technical
ture as follows:
Barriers to Trade (TBT) Committee.
E
a
2. Terminology
k 5 A e 2 (2)
S D
RT
2.1 Definitions:
where:
k = rate constant,
This guide is under the jurisdiction of ASTM Committee F02 on Primary
A = constant with the same time units as k,
Barrier Packaging and is the direct responsibility of Subcommittee F02.15 on
Chemical/Safety Properties.
T = temperature, K (°C + 273), and
Current edition approved March 1, 2019. Published May 2019. Originally
R = universal gas constant.
approved in 1996. Last previous edition approved in 2014 as F1416 – 96(2014).
When R = 0.001987 kcal/(mol · deg), the activation energy,
DOI: 10.1520/F1416-19.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F1416 − 96 (2019)
meets predetermined criteria and is no longer considered
suitable for its original purpose.
2.1.8.1 Discussion—In some cases, such as where patho-
genic microbial growth is involved, there may be a serious
health risk in using a product past its shelf life. In such cases,
the shelf life to be monitored should be conservative enough so
that its expiration is signaled well before a health concern
develops. It may be desirable to indicate even short occur-
rences of undesirably high temperatures. Other changes may
also occur, such as in color, texture, or rancidity, which render
a product unacceptable for its original use. For most perishable
products, the shelf life decreases with increasing temperature.
2.1.9 threshold-temperature time-temperature indicator—a
TTI that only changes at temperatures above a specific thresh-
old.
2.1.10 time-temperature indicator (TTI)—a device that can
be affixed to the package of a perishable product and that
exhibits a change in a physically measurable or visually
measurable property as a combined function of both time and
NOTE 1—This blank graph may be used to determine if the shelf life of
temperature. For example, properties that change include color,
a product exhibits standardArrhenius behavior.The plot axes are the log
light reflectance, or a moving boundary between two colors.
of the shelf life and the reciprocal of temperature. Note that the X-axis of
this plot is marked in Celsius degrees instead of inverse Kelvin degrees,
2.1.11 time-temperature integrator—see time-temperature
so that the spacing between degrees is not uniform. For ease of use, the
indicator.
Fahrenheit and Celsius temperatures are shown on the graph instead of the
2.1.11.1 Discussion—This term emphasizes the fact that the
inverse temperature. To use, plot the shelf life of the product at
indicator’s response is an integration of the effects of both time
temperatures for which it is known. If the shelf life follows theArrhenius
relationship, the points can be connected with a straight line. The
and temperature.
activation energy may be calculated by the equation in 2.1.1.1.
2.1.12 time-temperature monitor—see time-temperature in-
FIG. 1 Blank Arrhenius Plot
dicator.
2.2 Definitions of Terms Specific to This Standard:
E , is given in units of kcal/mol.
a
2.2.1 activation method—the method by which an inactive
When R = 0.00831 kJ/(mol · deg), the activation energy, E ,
a
TTI is changed to an active state.
is given in units of kJ/mol.
2.2.1.1 Discussion—This may include a physical activation
2.1.4.1 Discussion—This relationship also describes the de-
method, such as removing or breaking a barrier, or may require
pendence of the shelf life of many TTIs and perishable
raising the temperature to the normal operating range of the
productsontheeffectiveaveragetemperaturetowhichtheyare
TTI.
exposed. Since the shelf life is the time for the reaction to
proceed to a specific extent, theArrhenius relationship for shelf 2.2.2 inactive state—the state in which a TTI does not
life is given by the following formula:
respond to changes in temperature over time.
2.2.2.1 Discussion—Some types of indicators are active
E
a
LIFE 5 Be (3)
S D
when manufactured and kept essentially inactive by storage at
RT
low temperatures.
where B = constant with the same time units as LIFE.
2.2.3 slackened-out product—a product that is stored frozen
2.1.5 dual function time-temperature indicator— a TTI that
for an indeterminate time and then thawed (slackened out) for
combines both all-temperature and threshold-temperature
the final part of its distribution and use.
responses, overlaid in a single indicator in order to modify the
total time-temperature response.
3. Significance and Use
2.1.6 effective average temperature—the single constant
3.1 Expiration dates are often marked on the packages of
temperature that would have the same effect on the shelf life of
perishable products to indicate the presumed end of their shelf
a product as the actual temperature profile has for the same
lives. Since the shelf lives of most perishable products are
time period.
temperature dependent, the expiration date is determined by
2.1.7 hazard analysis and critical control points
assuming the product will be kept within a prescribed tempera-
(HACCP)—a method to control food quality and safety by
ture range for its entire life.Aproblem with this method is that
identifying and controlling those processing and distribution
there is no way to determine if the shelf life of a product has
steps where a food safety hazard may be prevented, eliminated,
been shortened by exposure to a higher temperature. A time-
or reduced to acceptable levels.
temperature indicator solves this problem when attached to the
2.1.8 shelf life—the time required for various changes to a package because it reaches its end point sooner when exposed
product to accumulate to the point where the product no longer to a higher temperature.
F1416 − 96 (2019)
3.2 In order to directly indicate the end of the shelf life, the remaining shelf life of a product based on the state of the
time-temperature indicator characteristics should be matched indicator. The shelf life history of the product m
...
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