Protecting your Products and your Brands

Overview of Microbial Control

Drywall Finishing CouncilSeptember 18, 2012

Discussion Topics

“In-Can Protection” for Gypsum Finishing Products Need for In-Can Protection Failure Issues Testing protocols Ecolabels

“Mold Control” for Wall Board and Finishing Products Paper Gypsum Core Testing protocols

Importance of Plant Hygiene and Raw Material Protection

In-Can Preservation

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Types of MicroorganismsMicrobes

Bacteria Fungi Algae

Mold Yeast

Filamentous Single cell

Key Organism forIn-Can Preservation

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Bacteria Growth Requirements Water Degradable nutrient source containing carbon

Latex emulsion Cellulosic thickener

Favorable temperature ~25 to 37°C

Varying oxygen concentrations Favorable pH

Bacteria: acidic or alkaline Fungi: acidic

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In-Can Issues due to Lack of Preservation

Odor

Discoloration

Viscosity change

Off-gassing

Lack of product performance for consumer

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In-can Preservation Example

Unpreserved paint Spoiled paint

Water

Solvent

Binder

Additives

Pigments

Historically solvents have aided product preservation

Water

Solvent

Binder

Additives

Pigments

Low VOC

Wall Finishing Products Needing Protection

Premixed Compounds Similar to Paint example Potential contamination from Raw Materials Bacterial inoculation in product use

Dry Mix Compounds Product is contaminated in mixing process Contractors retain mixed product for

days/weeks

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Detecting and Enumerating Bacterial Contamination in Products and Raw Materials

Dip slides

Streak plates Agar plate swabs

Dilution plating (agar) Total viable counts (TVCs)

Applicable to manufacturing facilities and formulation labs

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Dip Slides Agar on a paddle

Bacterial agar side 1 Fungal agar side 2

Common brands Hycheck Easicult (TTC indicator dye)

Quick and easy to use Solid surfaces Water-based materials Best used for +/- contamination evaluations

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Dip Slide Bacteria Enumeration Approximate CFU/mL measurements can be determined in liquid

materials (very rough estimate) CFU/mL = Colony Forming Units per milliliter = number of cells

Difficult to read due to product viscosity and colony color Dilution of product may be required (sterile water) TTC indicator dye is helpful

Paint: assume ~1 mL deposited Latex or slurry: assume ~0.25 mL deposited

~1 x 101 ~5 x 101 ~102 ~102 - 103 >103 ~5 x 101 ~2.5 x 102 ~102 - 103 ~103 - 104 >104

CFU/mL measurements

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Streak Plates Swab product on agar

Sterile swab Agar plate (TSA)

~0.1 mL spread evenly on agar surface

More accurate than dip slides Approximate volume known Easier to read due to spreading of product

Standard challenge test “streaks” Rating score commonly used instead of CFU/mL values

Commercially available

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Streak Plate Scores

SampleA

Sample B

Sample C

Sample D

Score: 004 3

Plating Results Score Approximate CFU/mL

No detectable survival 0 < 1 x 101

1–9 colonies 1 1 x 101 - 9 x 101

10–99 colonies 2 1 x 102 – 9.9 x 102

100–300 colonies 3 1 x 103 - 3 x 103

>300 colonies (smear) 4 > 3 x 103

Passing score: 0 or 1Failing score: 2 - 4

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Dilution Plating Total viable counts (TVCs)

Product sample is serially diluted to thin out the microbe population

Exactly 100 µl is evenly spread on an agar plate surface Cells grow into colonies for counting and CFU/mL determination Accurately enumerate from 101 to 109 CFU/mL Time consuming as compared to streak plates and dip slides

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Dilution Plating

Sample A

Sample B

10-8 dilution10-7 dilution10-6 dilution

3 x 108 CFU/mL

8 x 108 CFU/mL

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High-Throughput Challenge EvaluationsDow Proprietary Methodology

Validated to standard agar plate tests Generate large amounts of comparative performance data Quickly evaluate combinations for synergy or antagonism

Important for biocide optimization studies as VOC content becomes lower In-can preservative plus co-biocide Compare lab strains vs. manufacturing facility contaminants

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Ecolabels – Steps towards Sustainability

Originated primarily in USA and Europe Rapid global expansion – over 330 ecolabels Ecolabels certify final consumer products, however have lists of

accepted ingredients and/or ecological criteriea Most prohibit ingredients that could be classified as:

carcinogens, mutagens, reproductive toxins, hazardous air pollutants, or ozone-depleting compounds

Sustainability Staircase

Future Sustainability

Most Sustainable

More Sustainable

Not Sustainable

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Surface Protection

Surface Problems …. Microbial Growth

Nutrients

Humidity

Sunlight

Tem

pera

ture

Algal GrowthFungal Growth

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Types of Microorganisms

Microbes

Bacteria Fungi Algae

Mold Yeast

Key Organism forSurface Protection

Gypsum is hygroscopic and therefore can act as a reservoir of moisture to sustain mold

Both paper liners and additives to gypsum core and finishing products serve as carbon sources for mold

Presence of moisture necessary for mold growth

Mold Issues with Wallboard and Finishing Products

Other Potential Issues with Mold

Vinyl Wallcovering with either fabric or cellulosic backings

Wallcovering adhesives and sealants Coating surfaces Wood used in basic construction

Control of Mold

First line of defense are engineering considerations. Mold spores are everywhere and conditions of moisture must be right.

Since impractical at times and tight controls are not easily kept, “Material Preservation” is needed.

If possible, as many of the susceptible building materials should contain an effective fungicide that has a good environmental profile, is compatible with the substrates and of course safe to incorporate and an acceptable risk to the end use customer.

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Prevention of Dry Film Contamination:Add Effective Biocides

Physical properties requirements Low water solubility pH stable Compatible with wide range of products No effect on product properties No color Low mammalian toxicity and low ecotoxicity

Efficacy Against targeted microbes

Laboratory Methods for Measuring Fungal Resistance of Surfaces

ASTM D-3273: Resistance of a surface to mold growth via exposure in an environmental chamber (Coatings Test)

ASTM G-21: Determining the Resistance of Synthetic Polymeric Materials to Fungi

Method designed for polymers Direct inoculation

Aspergillus niger, Penicillium pinophilum, Chaetomium globosum, Trichoderma virens (Gliocladium), Aureobasidium pullulans

Samples in petri dish with agar 0-4 scoring

ASTM 5590 : Resistance of Coatings to Fungal Growth

TAPPI T487: Fungus Resistance of Paper and Paperboard

TAPPI T 487

VARIOUS TREATMENTS

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Industrial Hygiene

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Industrial Hygiene (IH)

Improving a manufacturing site’s physical condition, cleaning practices and sanitization procedures with respect to controlling and minimizing microbial contamination

Dual approach Manual cleaning Biocide treatments

Proactive microbial control Minimize manufacturing facility (“wild”) strains Maximize in-can preservative longevity and product shelf-life

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Importance of IH “Green” movement

Products are more susceptible to spoilage Use of natural materials Minimization of ingredients

Less robust in-can preservative systems Eco-certification programs

Lower biocide use levels Increased use of less effective biocides

More difficult to eliminate waste (“wash”) water Equipment cleaning Use in finished products

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Consequences of Poor IH Practices

Manufacturing facility impact Plugged filters, transfer lines, and spray nozzles Equipment corrosion Pump/machine failure

Facility operations interrupted Decreased production rate

Finished product contamination Consumer complaints Product recalls

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Reducing Microbial Dissemination

Internal industrial hygiene auditing Visual inspections (spoilage, odor)

Establish a stringent microbial sampling process (monthly) Dip slides (raw materials, paint) Swabbing to agar plates (equipment, raw materials, paint)

In-house testing capabilities 3rd party laboratory for microbial analysis

Plant audit by biocide supplier 1x per year

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Reducing Microbial Dissemination

General housekeeping Focus hygiene efforts on high water content areas Clean aqueous spills immediately Eliminate stagnate water (floor, trenches)

Equipment storage Avoid resting equipment on the floor

Transfer hoses, weigh-off buckets, sample dippers Close tank lids and cap hoses, lines, ports Flush, drain, dry, cap/cover

Conclusions

Dry wall applications present real opportunities for advanced Microbial Control

In Can Preservation Mold Control

Manufacturers can gain real value by partnering with a key biocide supplier

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Dow Microbial Control Industry Leadership

•Largest portfolio of globally registered biocide active chemistries

– Biocides to protect the finished product from mold and mildew (e.g. fungicides, algaecides)

– “Wet-state” preservatives – in-product and process– Biocides for decontamination (clean-up) and disinfection

•Best in class microbial testing capabilities

•Global manufacturing and supply

•Global product registration and stewardship– Product handling/safety expertise, regulatory support

Buffalo Grove, Illinois, USA

DMC Center of Excellence:

Microbiological Methodology

Shanghai, China

SingaporeMumbai, IndiaSão Paulo,Brazil

Dubai, United Arab Emirates

Querétaro, Mexico

Customer Application Centers: Laboratory Facilities

Buchs, Switzerland

DMC Center of Excellence:

Formulations

Spring House, Pennsylvania, USA

DMC Center of Excellence: Actives

Delivery

Soma, Japan

Warsaw, Poland

Altona, Australia