ASTM D4576-16(2021)

• Abstract:

  SIGNIFICANCE AND USE; 4.1 This test method provides a technique for evaluating mold growth resistance characteristics of Wet Blue and Wet White, 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 and Wet White 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 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. ; 1.5 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use. ; 1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

• Status: Published
• Publication Date: 31-Aug-2021
• ICS: 59.140.30 - Leather and furs
• Technical Committee: D31 - Leather
• Drafting Committee: D31.02 - Wet Blue

Overview

ASTM D4576-16(2021) is the internationally recognized standard test method for assessing the mold growth resistance of Wet Blue and Wet White hides used in leather manufacturing. Developed by ASTM International, this standard offers a controlled laboratory technique for evaluating these materials under storage and shipping conditions. It assists stakeholders in predicting the duration that Wet Blue and Wet White can be stored before mold becomes a concern, supporting risk assessment in the supply chain for leather products.

Key Topics

• Test Specimen & Sampling: Describes protocols for preparing and sampling Wet Blue (chromium-tanned) and Wet White (non-chromium, non-iron tanned) hides, focusing on samples with about 50% moisture content.
• Resistance Evaluation: Outlines comparative testing using controls of known resistance to determine the relative susceptibility of test specimens to mold growth.
• Laboratory Flexibility: Permits adjustment of incubation time, temperature, humidity, inoculum, sampling area, and controls to match laboratory or local requirements, provided these conditions are standardized within the test.
• Incubation & Interpretation: Specifies conditions and a rating scale (from 0 to 4) based on the percentage of the specimen surface covered by mold following incubation.
• Environmental & Safety Practices: Stresses the importance of hygiene, contamination control, and safety when performing tests, and notes the user’s responsibility to adhere to regulatory and safety guidelines.

Applications

The ASTM D4576-16(2021) standard is widely utilized in:

• Leather Manufacturing Quality Control: Helps manufacturers determine the susceptibility of Wet Blue and Wet White hides to mold prior to further processing or shipment, improving overall leather product quality.
• Storage and Logistics Assessment: Assists warehouses and shipping professionals in assessing the likely shelf-life and storage limitations of hides, enabling proactive steps to minimize spoilage and waste.
• Fungicide Evaluation: Offers a framework for comparing the efficacy of fungicidal treatments, though it may not be suitable for proteins that inactivate certain fungicides (such as alkyldimethylbenzyl ammonium chlorides).
• Product Development and R&D: Supports research teams in developing new hide processing treatments aimed at increasing mold resistance during storage and transport.

Related Standards

For comprehensive management and testing of hides and leathers, organizations may also reference these related ASTM standards:

• ASTM D5035 - Standard Test Method for Breaking Force and Elongation of Textile Fabrics (used for physical properties of leathers)
• ASTM D2813 - Standard Practice for Sampling Leather for Physical and Chemical Tests
• ASTM D2099 - Standard Practice for Fungal Resistance of Paper and Paperboard
• ISO 11799 - Information and documentation - Document storage requirements for archives and libraries (relevant to storage environments)

Practical Value

Using ASTM D4576-16(2021), laboratories and quality managers can:

• Identify risks of mold contamination during storage and shipment phases.
• Validate storage protocols and environmental controls in the hide and leather value chain.
• Benchmark materials through standardized procedures, allowing manufacturers and buyers to compare products reliably.
• Support documentation for compliance with international quality and trade requirements.

By following this standard, stakeholders enhance product durability, maintain market reputation, and meet industry-specific mold resistance requirements in the global leather sector.

Keywords: ASTM D4576, mold growth resistance, Wet Blue, Wet White, leather manufacturing, storage testing, shipping, quality control, fungal contamination, leather industry standards.

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D4576 − 16 (Reapproved 2021)
Standard Test Method for
Mold Growth Resistance of Wet Blue and Wet White
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),
growthresistanceofWetBlueandWetWhitesubjecttostorage
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 and Wet White test specimens are surrounded
includes alkyldimethylbenzyl ammonium chlorides.
by but not 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
run control of known resistance. Success or failure is deter- asapercentageoftheWetBlueandWetWhitesurfacecovered
by mold.
mined by the amount of mold growth relative to the control.
1.3 To allow use of this test method by any laboratory, 3.3 ResistancetomoldgrowthoftheWetBlueorWetWhite
test specimen is determined by comparison with Wet Blue or
flexibility has been permitted in times, temperature, and
humidity of incubation, inoculum, hide sampling area, and Wet White of known resistance characteristics (the control),
that is tested simultaneously.
choiceofcontrol.Thesemaybeadjustedtofitlocalconditions
but must be standardized.
4. Significance and Use
1.4 The values stated in SI units are to be regarded as
4.1 This test method provides a technique for evaluating
standard. No other units of measurement are included in this
mold growth resistance characteristics of Wet Blue and Wet
standard.
White, and should assist in the prediction of storage time
1.5 This standard does not purport to address all of the
before molding occurs.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro- 4.2 Thedegreeofcorrelationbetweenthistestandcommer-
priate safety, health, and environmental practices and deter-
cial quantities of Wet Blue and Wet White in storage or
mine the applicability of regulatory limitations prior to use. shipment situations, or both, has not been fully determined.
1.6 This international standard was developed in accor-
dance with internationally recognized principles on standard- 5. Interferences
ization established in the Decision on Principles for the
5.1 Acommon interference is contamination of plates, agar,
Development of International Standards, Guides and Recom-
or samples by unwanted organisms that settle in from the
mendations issued by the World Trade Organization Technical
environment.
Barriers to Trade (TBT) Committee.
5.2 Volatility and Leachability of Biocides—A “zone of
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:
2.1.1 Wet Blue—hide or skin, or split of a hide or skin,
6. Apparatus
tanned with basic chromium sulfate, containing approximately
6.1 Petri Dishes, 120 mm diameter. Sterile plastic dispos-
50% moisture and having an acidic pH.
able dishes are preferred.
6.2 Incubator, or location providing similar conditions be-
1 ing free of drafts, and capable of a constant (62 °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 Sept. 1, 2021. Published October 2021. Originally
6.3 Medicine droppers,disposableplastictypedelivering30
approved in 1986. Last previous edition approved in 2016 as D4576-16. DOI:
10.1520/D4576-16R21. to 35 drops per mL.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D4576 − 16 (2021)
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 and Wet White.
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 clea
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