Transcript Slide 1

Protecting your Products and your Brands
Overview of Microbial Control
Drywall Finishing Council
September 18, 2012
Discussion Topics
 “In-Can Protection” for Gypsum Finishing Products
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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 Microorganisms
Microbes
Key Organism for
In-Can Preservation
Bacteria
Fungi
Mold
Filamentous
Algae
Yeast
Single cell
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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
Solvent
Water
Additives
Binder
Pigments
Unpreserved paint
Spoiled paint
 Historically solvents have aided product preservation
Solvent
Water
Low VOC
Additives
Binder
Pigments
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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
Applicable to manufacturing
facilities and formulation labs
 Agar plate swabs
 Dilution plating (agar)
 Total viable counts (TVCs)
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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
~1 x 101
~5 x 101
~102
~102 - 103
>103
Latex or slurry: assume ~0.25 mL deposited
~5 x 101
~2.5 x 102 ~102 - 103
CFU/mL measurements
~103 - 104
>104
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Streak Plates
 Swab product on agar
 Sterile swab
 Agar plate (TSA)
Commercially
available
 ~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
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Streak Plate Scores
Sample
A
Sample
B
Sample
C
Sample
D
Passing score: 0 or 1
Failing score: 2 - 4
Score:
4
3
0
0
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
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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
10-6 dilution
Sample A
Sample B
10-7 dilution
10-8 dilution
3 x 108
CFU/mL
8 x 108
CFU/mL
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High-Throughput Challenge Evaluations
Dow 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
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Sustainability Staircase
Future Sustainability
Most Sustainable
More Sustainable
Not Sustainable
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Surface Protection
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Surface Problems …. Microbial Growth
Algal Growth
Humidity
Nutrients
Fungal Growth
Temperature
Sunlight
Types of Microorganisms
Microbes
Bacteria
Fungi
Mold
Algae
Yeast
Key Organism for
Surface Protection
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Mold Issues with Wallboard
and Finishing Products
 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
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.
Prevention of Dry Film Contamination:
Add Effective Biocides
 Physical properties requirements
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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
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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
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
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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
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Customer Application Centers: Laboratory Facilities
Buffalo Grove,
Illinois, USA
Spring House,
Pennsylvania, USA
Buchs,
Switzerland
DMC Center of
Excellence:
Microbiological
Methodology
DMC Center of
Excellence: Actives
Delivery
DMC Center of
Excellence:
Formulations
Dubai, United
Arab Emirates
Shanghai, China
Soma, Japan
Querétaro, Mexico
São Paulo,
Brazil
Mumbai, India
Singapore
Altona, Australia
Warsaw, Poland