ASTM D4576-08(2013)
(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
4.1 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.
4.2 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 and wet white 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 For mold growth resistance of wet white, the procedure is identical, substitute wet white for wet blue in the standard method.
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.6 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: D4576 − 08(Reapproved 2013)
Standard Test Method for
Mold Growth Resistance of Wet Blue
This standard is issued under the fixed designation D4576; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2.1.2 wet white—a hide or skin, or split of a hide or skin
tanned with organic or non-organic tanning agents (excluding
1.1 This test method covers the determination of mold
chromium or iron containing agents and vegetable extracts),
growth resistance of wet blue and wet white subject to storage
containing approximately 50 % moisture.
and shipping requirements and intended for use in leather
manufacturing. This test method may not be suitable to
3. Summary of Test Method
evaluate fungicides that are inactivated by proteins. This
3.1 Wet blue test specimens are surrounded by but not
includes alkyldimethylbenzyl ammonium chlorides.
covered with agar, inoculated, and incubated.
1.2 Conclusions about mold growth resistance are drawn
3.2 After various incubation periods, mold growth is rated
from the results by comparing the test with a simultaneously
as a percentage of the wet blue surface covered by mold.
run control of known resistance. Success or failure is deter-
mined by the amount of mold growth relative to the control.
3.3 Resistancetomoldgrowthofthewetbluetestspecimen
is determined by comparison with wet blue of known resis-
1.3 To allow use of this test method by any laboratory,
tancecharacteristics(thecontrol),thatistestedsimultaneously.
flexibility has been permitted in times, temperature, and
humidity of incubation, inoculum, hide sampling area, and
4. Significance and Use
choiceofcontrol.Thesemaybeadjustedtofitlocalconditions
4.1 This test method provides a technique for evaluating
but must be standardized.
mold growth resistance characteristics of wet blue, and should
1.4 For mold growth resistance of wet white, the procedure
assist in the prediction of storage time before molding occurs.
is identical, substitute wet white for wet blue in the standard
4.2 Thedegreeofcorrelationbetweenthistestandcommer-
method.
cial quantities of wet blue in storage or shipment situations, or
1.5 The values stated in SI units are to be regarded as
both, has not been fully determined.
standard. No other units of measurement are included in this
standard.
5. Interferences
1.6 This standard does not purport to address all of the
5.1 Acommon interference is contamination of plates, agar,
safety concerns, if any, associated with its use. It is the
or samples by unwanted organisms that settle in from the
responsibility of the user of this standard to establish appro-
environment.
priate safety and health practices and determine the applica-
5.2 Volatility and Leachability of Biocides—A “zone of
bility of regulatory limitations prior to use.
inhibition” where no mold grows on the agar adjacent to the
2. Terminology specimen indicates that the fungicide may leach.
2.1 Definitions of Terms Specific to This Standard:
6. Apparatus
2.1.1 wet blue—hide or skin, or split of a hide or skin,
6.1 Petri Dishes, 120 mm diameter. Sterile plastic dispos-
tanned with basic chromium sulfate, containing approximately
able dishes are preferred.
50% moisture and having an acidic pH.
6.2 Incubator, or location providing similar conditions be-
1 ing free of drafts, and capable of a constant (6 2°C) tempera-
ThistestmethodisunderthejurisdictionofASTMCommitteeD31onLeather
and is the direct responsibility of Subcommittee D31.02 on Wet Blue. ture within the 26 to 30°C range.
Current edition approved May 1, 2013. Published May 2013. Originally
6.3 Medicine droppers,disposableplastictypedelivering30
approved in 1986. Last previous edition approved in 2008 as D4576-08. DOI:
to 35 drops per mL.
10.1520/D4576-08R13.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D4576 − 08 (2013)
7. Reagents and Materials 9.3.1 Reduce working stock of 1×10 spores per mL to
2 1×10 by diluting 1 volume to 10 volumes with water.
7.1 Potato Dextrose Agar, a dehydrated plating medium
9.3.1.1 Use tap water, that has been freshly boiled for 20
used in culturing yeasts and molds from dairy products.
min. and cooled to room temperature, for making dilutions.
3 6
7.2 Inoculum, Aspergillus niger 1×10 spores per mL, or
9.3.1.2 Prepare only enough diluted suspension for use in a
other organism or a combination of organisms known to be
48-hour period.
indigenous to the storage area of the wet blue.
9.3.1.3 Keep organism stock suspensions refrigerated at
about 4°C. Do not freeze.
8. Sampling, Test Specimen, and Test Units
9.3.2 Use three drops of 1×10 spores per milliliter per
8.1 Take test specimens from equivalent hide locations (for
plate using a plastic disposable medicine dropper. Deposit one
example, butt area) for both test and control.
drop directly on the sample and one drop to either side as
shown in Fig. 1.
8.2 If unable to test immediately, hold test specimens in
9.3.3 Let dishes set about 1 h.
separate plastic bags and keep cool.
NOTE 3—If moved too quickly the inoculum runs over the specimen
8.3 Test specimens should be a square, with a side of 25.4
surface.
mm (1 in.).
NOTE 4—Keep work area as clean and aseptic as possible. Work in an
area of minimal air circulation while handling wet blue, pouring agar, and
8.4 Use three test specimens for each test unit of wet blue
inocula
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