ASTM D4576-86(1996)
(Test Method)Standard Test Method for Mold Growth Resistance of Wet Blue
Standard Test Method for Mold Growth Resistance of Wet Blue
SCOPE
1.1 This test method covers the determination of mold growth resistance of wet blue subject to storage and shipping requirements and intended for use in leather manufacturing. This test method may not be suitable to evaluate fungicides that are inactivated by proteins. This includes alkyldimethylbenzyl ammonium chlorides.
1.2 Conclusions about mold growth resistance are drawn from the results by comparing the test with a simultaneously run control of known resistance. Success or failure is determined by the amount of mold growth relative to the control.
1.3 To allow use of this test method by any laboratory, flexibility has been permitted in times, temperature, and humidity of incubation, inoculum, hide sampling area, and choice of control. These may be adjusted to fit local conditions but must be standardized.
1.4 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 and health practices and determine the applicability of regulatory limitations prior to use.
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Designation: D 4576 – 86 (Reapproved 1996)
Standard Test Method for
Mold Growth Resistance of Blue Stock (Leather)
This standard is issued under the fixed designation D 4576; 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 4.2 The degree of correlation between this test and blue
stock in commercial quantities in storage or shipment situa-
1.1 This test method covers the determination of mold
tions, or both, has not been fully determined.
resistance of blue stock subject to storage and shipping
requirements and intended for use in leather manufacturing.
5. Interferences
This test method may not be suitable to evaluate fungicides that
5.1 A common interference is contamination of plates, agar,
are inactivated by proteins. This includes alkyldimethylbenzyl
or samples by unwanted organisms that settle in from the
ammonium chlorides.
environment.
1.2 Conclusions about mold resistance are drawn from the
5.2 Volatility and Leachability of Biocides—A “zone of
results by comparing the test with a simultaneously run control
inhibition” where no mold grows on the agar adjacent to the
of known resistance. Success or failure is determined by the
specimen indicates that the fungicide may leach.
amount of mold growth relative to the control.
1.3 To allow use of this test method by any laboratory,
6. Apparatus
flexibility has been permitted in times, temperature, and
6.1 Petri Dishes—120 mm diameter. Sterile plastic dispos-
humidity of incubation, inoculum, hide sampling area, and
able dishes are preferred.
choice of control. These may be adjusted to fit local conditions
6.2 Incubator, or other location, free of drafts, and capable
but must be standardized.
of a constant (6 2°C) temperature within the 26 to 30°C range,
1.4 This standard does not purport to address all of the
6.3 Medicine droppers, disposable plastic type delivering 30
safety concerns, if any, associated with its use. It is the
to 35 drops per mL.
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
7. Reagents and Materials
bility of regulatory limitations prior to use.
7.1 Potato Dextrose Agar, a dehydrated plating medium
used in culturing yeasts and molds from dairy products.
2. Terminology
3 6
7.2 Inoculum, Aspergillus niger 1 3 10 spores per mL, or
2.1 Definition of Term Specific to This Standard:
other organism or a combination of organisms known to be
2.1.1 blue stock—hide or skin, or split of a hide or skin,
indigenous to the storage area or the blue stock.
tanned with basic chromium sulfate, containing approximately
50 % moisture and having an acid pH.
8. Sampling, Test Specimen, and Test Units
8.1 Take test specimens from equivalent hide locations (for
3. Summary of Test Method
example, butt area) for both test and control.
3.1 Blue stock test specimens are surrounded by but not
8.2 If unable to test immediately, hold test specimens in
covered with agar, inoculated, and incubated.
separate plastic bags and keep cool.
3.2 After various incubation periods, mold growth is rated
8.3 Cut test specimens one in. square.
as a percentage of the blue stock covered.
8.4 Use three test specimens for each test unit or blue stock
3.3 Resistance to mold growth of the subject blue stock is
surface to be evaluated.
determined by comparison with blue stock of known resistance
characteristics (the control), that is tested simultaneously.
9. Procedure
9.1 Agar Preparation:
4. Significance and Use
9.1.1 Agar Requirements—A split blue stock sample re-
4.1 This test method provides a technique for evaluating
quires about 25 mL solution and unsplit blue stock requires
mold growth resistance characteristics of blue stock and should
assist in the prediction of storage time before molding occurs.
A product that meets the requirements of this method is Potato Dextrose Agar
stock no. 0013-01-4, available from Difco Labs, P.O. Box 1058A, Detroit,
MI 28232.
1 3
This test method is under the jurisdiction of ASTM Committee D31 on Leather An inoculum that meets the requirements of this method is available from
and is the direct responsibility of Subcommittee D31.02 on Blue Stock. Chemtan Company, Inc., Box C, Exeter, NH 03833-0050, prepared by Abbott
Current edition approved June 9, 1986. Published July 1986. Laboratories.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
D 4576
NOTE 3—If moved too quickly the inoculum runs over the specimen
about 40 mL. Calculate number of mL of agar required for tests
surface.
to be performed, allowing 50 mL for vitality check.
NOTE 4—Keep work area as clean and aseptic as possible. Fans or fast
9.1.2 Weigh 3.9 g potato dextrose agar for every 100 mL of
moving air should be stopped while handling blue stock, pouring agar, and
agar required.
inoculatin
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