ASTM F874-98

NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: F 874 – 98
Standard Test Method for
Temperature Measurement and Profiling for Microwave
Susceptors
This standard is issued under the fixed designation F 874; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope 3. Apparatus
1.1 This is a test method for measuring surface temperatures 3.1 Microwave Oven, no turntable, unmodified except for
attained by microwave interactive packaging and cooking aids small holes to allow for probe lead access to the oven cavity.
(that is, susceptors). It is useful for measuring susceptor/food The oven should be calibrated in accordance with Test Method
interface temperatures during microwave preparation of foods F 1317.
with susceptor-based packaging, heating pads, and crisping 3.2 Fluoroptic Thermometry System.
sleeves, etc. It may also be used to measure the temperature of 3.3 Vials, headspace, 20 mL.
a susceptor exposed to extractives testing or in a liquid 3.4 Septa, polytetrafluorethylene (PTFE) polymer faced sili-
extraction cell to be used for nonvolatile extractives testing. cone rubber.
The latter procedures are performed to establish test conditions 3.5 Vial Crimp Caps.
for conducting extraction and migration studies using tempera- 3.6 Microwave Nonvolatile Extraction Cell —This cell
ture versus time profiles approximating those for actual micro- must be constructed of PTFE-fluorocarbon polymer. Addi-
wave preparation of the product. tional details on this cell may be found in Test Method F 1349.
1.1.1 Several of the steps of this test method are taken 3.7 Beakers, 600 and 250 mL, or other sizes as appropriate.
directly from Test Method F 1308 which gives extraction 3.8 Aluminum Foil, household roll.
testing procedures for susceptors. 3.9 Adhesive Tape, such as Kapton high-temperature tape,
1.2 This standard does not purport to address all of the vinyl tape, silicone tape, etc.
safety concerns, if any, associated with its use. It is the 3.10 High-Vacuum Silicone Grease.
responsibility of the user of this standard to establish appro- 3.11 Syringe Needle, 13 gage diameter.
priate safety and health practices and determine the applica- 3.12 Corn Oil, Miglyol 812 (a fractionated coconut oil), or
bility of regulatory limitations prior to use. synthetic fat simulant HB 307. See Test Method F 1349 for
details.
2. Referenced Documents
3.13 Petri Dishes.
2.1 ASTM Standards:
3.14 Fan, tabletop.
F 1308 Test Method for Quantitating Volatile Extractables 3.15 Blue Ice.
in Microwave Susceptors Used for Food Products
F 1317 Test Method for Calibration of Microwave Ovens
Luxtron Model 750 or equivalent, with Luxtron MIH or MIW temperature
F 1349 Test Method for Nonvolatile Ultraviolet (UV) Ab-
probes, or equivalent. Available from Luxtron Inc., 106 Terra Bella Ave., Mountain
sorbing Extractables from Microwave Susceptors
View, CA 90403.
F 1500 Test Method for Quantitating Non-UV-Absorbing
Available from Shamrock Glass Co., 200 N. Delaware Ave., Seaford, DE 19973
(Catalog No. 667601) or Chemical Research Supplies, PO Box 888, Addison, IL
Nonvolatile Extractables from Microwave Susceptors Uti-
2 60101 (Catalog No. 237502), or equivalent.
lizing Solvents as Food Simulants
Available from Shamrock Glass Co. (Catalog No. 778173A) or Hewlett
Packard (Catalog No. 5080-8726), or equivalent.
Available from Shamrock Glass Co. (Catalog No. 778704) or Hewlett Packard
Computer Supplies Operation, PO Box 62124, San Francisco, CA 94162 (Catalog
This test method is under the jurisdiction of ASTM Committee F-2 on Flexible No. 07675-20625), or equivalent.
Barrier Materials and is the direct responsibility of Subcommittee F02.30 on Test Available from Waldorf Corp., 2250 Wabash Ave., St. Paul, MN 55114.
Methods. PTFE-fluorocarbon polymer materials may be purchased from Read Plastics,
Current edition approved Oct. 10, 1998. Published March 1999. Originally Rockville, MD, or equivalent.
published as F 874 – 90. Last previous edition F 874 – 91. Available from Curtin Mattheson Scientific (Catalog No. 301-911).
2 10
Annual Book of ASTM Standards, Vol 15.09. Available from Curtin Mattheson Scientific (Catalog No. 218-636).
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
F874–98
3.16 Vials, for alternative profile method, 40-mL clear 5.4 For products prepared on a susceptor board, such as
vials. microwave pizza, the probe should be immobilized to the
3.17 Screw Caps. susceptor board in parallel contact by applying a suitable
adhesive tape 0.5 in. behind the probe tip.
4. Procedure
5.5 For products without free fat or oil at the food susceptor
4.1 General: interface, it is advisable to apply high-vacuum silicone grease
4.1.1 Start all tests with a cool microwave oven, that is, to the tip of the probe to assure good thermal contact with the
ambient temperature. Use a fan and blue ice to cool oven floor susceptor.
or any other reliable method to suitably return the oven to 5.6 Microwave at full power for the maximum directed
ambient temperature between replicates. cooking time of the product, recording the temperature of each
4.1.2 Test three replicates per variable. probe, preferably at 5-s intervals, but at intervals not to exceed
15 s. It is suggested that readings be taken at 1-s intervals if
5. Measurement of Food/Susceptor Interface
possible, in order to generate a smoother curve. Calculate the
Temperature During Microwave Cooking
average of the replicate runs at each recorded time for each
5.1 Place product in center of the microwave oven as a
probe position. Do not use data if discontinuities appear in plot
consumer would. Mark the position of first replicate on oven (indicative of loss of susceptor/probe contact).
floor, and position subsequent replicates similarly.
6. Temperature Profiling of Susceptors in Vials Used for
5.2 Position probes at food susceptor interface in such a
Volatile Extractives Testing
manner that good probe/susceptor contact is maintained during
cooking, disturbing the food load as little as possible. The 6.1 First determine the temperature versus time profile for
analyst may wish to position multiple probes on different
the product during microwave preparation in accordance with
regions of the susceptor, such as the center and edge, as the Section 5.
2 2
temperature attained at different locations may differ signifi-
6.2 Cut a 10 by 65-mm (6.5 cm or 1-in. ) portion from the
cantly. susceptor sample to be tested. Insert carefully into vial,
5.2.1 If the nature of the product permits, the analyst may
positioning the sample on the vial side, with the active side
wish to determine whether probes positioned parallel to the facing into the vial.
susceptor surface, or abutted to the susceptor surface would
6.3 Using a 13-gage syringe needle, pierce a hole into a
result in better temperature measurement as evidenced by septum, place septum on vial and crimp.
better reproducibility between replicate runs and less discon-
6.4 Insert one temperature–sensing probe through the sep-
tinuity, due to loss of contact, of temperature readings versus tum hole into the vial and manipulate it until it is in contact
time.
with the active face of the susceptor material.
5.3 For in-package measurements for products such as
6.5 Place vial on its side in the center of the microwave
microwave popcorn, probe access into the package is achieved
oven, marking the exact location on the oven floor for
by drilling approximately 0.1-in. holes through the package.
subsequent replicates. Place the cap of the vial towards the
(See Fig. 1 for probe placement inside a popcorn bag.) It is also
probe access port in the oven cavity, with susceptor active face
advisable to route the probes along the bottom of the package
up.
to avoid disruption of probe/susceptor contact as the bag
6.6 As an alternative to 6.2 through 6.5, multiple probes can
expands during cooking. If it has been demonstrated that the
be used for doing temperature profiling, using the following
outer bag surface and inner bag surface temperatures are
procedure. Cut a 10 by 65-mm portion from the susceptor
equivalent, then taping the probes to the outer surface would be
satisfactory.
Available from Alltech Associates, Inc. 2051 Waukegan Rd., Deerfield, IL
60015 (Catalog No. 9534), or equivalent.
Available from Alltech Associates, Inc., (Catalog No. 95321), or equivalent.
FIG. 1 Probe Configuration for Popcorn Bag Temperature FIG. 2 Effect of Foil Sleeve Window Size (cm ) on Temperature
Measurement Attained by Frozen Fish Product Susceptor
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
F874–98
6.7.2 Use of a water load is recommended for products
which do not contain large amounts of frozen water such as
popcorn and pizza. For products containing large amounts of
frozen water such as frozen fish,
...