ASTM D4576-01(2006)
(Test Method)Standard Test Method for Mold Growth Resistance of Wet Blue
Standard Test Method for Mold Growth Resistance of Wet Blue
SIGNIFICANCE AND USE
This test method provides a technique for evaluating mold growth resistance characteristics of wet blue, and should assist in the prediction of storage time before molding occurs.
The degree of correlation between this test and commercial quantities of wet blue in storage or shipment situations, or both, has not been fully determined.
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.
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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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:D4576–01(Reapproved2006)
Standard Test Method for
Mold Growth Resistance of Wet Blue
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. Significance and Use
1.1 This test method covers the determination of mold 4.1 This test method provides a technique for evaluating
growth resistance of wet blue subject to storage and shipping mold growth resistance characteristics of wet blue, and should
requirements and intended for use in leather manufacturing. assist in the prediction of storage time before molding occurs.
Thistestmethodmaynotbesuitabletoevaluatefungicidesthat 4.2 The degree of correlation between this test and commer-
are inactivated by proteins. This includes alkyldimethylbenzyl cial quantities of wet blue in storage or shipment situations, or
ammonium chlorides. both, has not been fully determined.
1.2 Conclusions about mold growth resistance are drawn
5. Interferences
from the results by comparing the test with a simultaneously
run control of known resistance. Success or failure is deter- 5.1 Acommon interference is contamination of plates, agar,
or samples by unwanted organisms that settle in from the
mined by the amount of mold growth relative to the control.
1.3 To allow use of this test method by any laboratory, environment.
5.2 Volatility and Leachability of Biocides—A “zone of
flexibility has been permitted in times, temperature, and
humidity of incubation, inoculum, hide sampling area, and inhibition” where no mold grows on the agar adjacent to the
specimen indicates that the fungicide may leach.
choice of control. These may be adjusted to fit local conditions
but must be standardized.
6. Apparatus
1.4 This standard does not purport to address all of the
6.1 Petri Dishes, 120 mm diameter. Sterile plastic dispos-
safety concerns, if any, associated with its use. It is the
able dishes are preferred.
responsibility of the user of this standard to establish appro-
6.2 Incubator, or location providing similar conditions be-
priate safety and health practices and determine the applica-
ing free of drafts, and capable of a constant (6 2°C) tempera-
bility of regulatory limitations prior to use.
ture within the 26 to 30°C range.
2. Terminology
6.3 Medicine droppers,disposableplastictypedelivering30
2.1 Definition of Term Specific to This Standard: to 35 drops per mL.
2.1.1 wet blue—hide or skin, or split of a hide or skin,
7. Reagents and Materials
tanned with basic chromium sulfate, containing approximately
7.1 Potato Dextrose Agar, a dehydrated plating medium
50 % moisture and having an acidic pH.
used in culturing yeasts and molds from dairy products.
3 6
3. Summary of Test Method
7.2 Inoculum, Aspergillus niger 1 3 10 spores per mL, or
other organism or a combination of organisms known to be
3.1 Wet blue test specimens are surrounded by but not
covered with agar, inoculated, and incubated. indigenous to the storage area of the wet blue.
3.2 After various incubation periods, mold growth is rated
8. Sampling, Test Specimen, and Test Units
as a percentage of the wet blue surface covered by mold.
8.1 Take test specimens from equivalent hide locations (for
3.3 Resistance to mold growth of the wet blue test specimen
example, butt area) for both test and control.
is determined by comparison with wet blue of known resis-
tance characteristics (the control), that is tested simultaneously.
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,
This test method is under the jurisdiction ofASTM Committee D31 on Leather MI 28232.
and is the direct responsibility of Subcommittee D31.02 on Blue Stock. An inoculum that meets the requirements of this method is available from
Current edition approved Oct. 1, 2006. Published November 2006. Originally Chemtan Company, Inc., Box C, Exeter, NH 03833-0050, prepared by Abbott
approved in 1986. Last previous edition approved in 2001 as D 4576 - 01. Laboratories.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D4576–01 (2006)
8.2 If unable to test immediately, hold test specimens in
separate plastic bags and keep cool.
8.3 Test specimens should be a square, with a side of 25.4
mm (1 in.).
8.4 Use three test specimens for each test unit of wet blue
surface to be evaluated.
9. Procedure
9.1 Agar Preparation:
9.1.1 Agar Requirements—A split wet blue test specimen
requires about 25 mL solution and an unsplit wet blue test
specimenrequiresabout40mL.Calculatenumberofmillilitres
of agar required for tests to be performed, allowing 50 mL for
vitality check.
9.1.2 Weighout3.9gpotatodextroseagarforevery100mL
of agar required.
FIG. 1 Specimen with inoculum locations shown (X)
9.1.3 Pour a volume of water equivalent to total millilitres
of agar solution to bea
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