MadgeTech EGGTEMP-RH Application Note

Application Note

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ΔH/RT

ΔH/RTΔH/RT

Mean Kinetic Temperature

What is Mean Kinetic Temperature?

Mean Kinetic Temperature (MKT) is a simplified way of expressing the overall effect of
temperature fluctuations during storage or shipment of perishable goods. Consider the following
example:

EXAMPLE:

A dozen eggs sat:
In a 20°C room for 2 hours
In a 2°C refrigerator for 4 hours
And on a 25°C loading dock for 1 hour

How is Mean Kinetic Temperature Calculated?

Technically speaking, MKT is an expression of cumulative thermal stress experienced by a
product at varying temperatures during storage and distribution. In other words, MKT is a
calculated, single temperature that is analogous to the effects of temperature variations over a
period of time.

MKT is not a simple weighted average. The calculation of MKT gives the higher temperatures a
greater weight when computing the average than would a simple numerical average or an
arithmetic mean. This weighting is determined by a geometric transformation the natural
logarithm of the absolute temperature.

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single derived temperature which, if maintained over a defined period, would afford the same
thermal challenge to a pharmaceutical product as would have been experienced over a range of

By using this unequal weighting pf the higher temperatures in a temperature series, MKT takes
into consideration the accelerated rate of thermal degradation of materials at these higher
temperatures. Therefore, MKT provides for the non-linear effect of temperature.

MKT is expressed as:

Where: ΔH = activation energy (typically from 60 to 100 kJ/mol for solids and liquids)
R = 8.314472 J/mol-K (universal gas constant)
T = temperature in degrees K
n = the number of sample periods over which data is collected

Note: ln is the natural log and ex is the natural log base.

Mean Kinetic Temperature DOC-AN00005-00 REV D 2014.12.22 page 1 of 2

Why is MKT Important in the Life of Pharmaceuticals and Perishable Goods?

The pharmaceutical and food industries are two closely regulated markets. The FDA provides
regulations that require warehouse and shipment temperatures to be closely controlled and
monitored. In addition, The FDA requires well documented verification of these storage
environments and any corrective actions taken if temperatures exceed specified storage
conditions. The calculation of MKT is regarded by the FDA as an action taken to verify if a
particular perishable has exceeded storage conditions.

In addition to compliance with the FDA regulations, MKT can help distributors and
manufacturers determine if improper storage and handling of goods that may have occurred
during shipment and/or unloading, has affected the shelf life of their product.

How Does MadgeTech Make MKT Simple?

shown in the summary report below:

Application Note

MadgeTech Inc.
[phone] Phone
[phone] Fax
www.madgetech.com
[e-mail]

6 Warner Road
Warner NH 03278

The MadgeTech algorithm has been validated against the United States Pharmacopeia (USP) and
will yield a value within 0.1°C for all inputs. It is also important to note that the MadgeTech
software uses constants that are more recent and marginally more accurate than the USP.
MadgeTech obtains these constants from the CODATA/ NIST recommended values.

The software assumes activation energy of 83.14472 kJ/mol for its calculation. In fact, any value
between 60 and 100 kJ/mol, which covers most solids and liquids, will have only a small effect
on the final value.

Of course, extreme temperature even over a very small time period can damage most foods or
pharmaceuticals. Per the above example, putting an egg in a 75°C oven for 1/2 hour will bring
the MKT to 45.4°C, but the egg ill be irreversibly damaged (ie. Cooked). Consequently, there are
maximum and minimum temperature limits established by the FDA. MadgeTech data loggers
make monitoring these extremes easy with user settable alarm limits so out-of-limit temperatures
can be easily identified.

Any data downloaded from a MadgeTech temperature data logger offers the user instant access
to MKT and the vital information that our users need to comply with FDA regulations and/or
make cost effective decisions on the acceptance or storage of perishable goods.

Mean Kinetic Temperature DOC-AN00005-00 REV D 2014.12.22 page 2 of 2