Assessment of the Level of Microbial Contamination in Cotton and Synthetic Fibers Destined for the Use in Nonwoven Applications

Transcription

1 Assessment of the Level of Microbial Contamination in Cotton and Synthetic Fibers Destined for the Use in Nonwoven Applications Doug J Hinchliffe, Anthony De Lucca, Brian Condon, Jan O Regan, Julie Clemmons, Linghe Zeng, Richard K Byler, Hiram Allen, Michael Reynolds, Michael Santiago Cintron, Crista Madison

2 Quality Production Microbial burden measurements are crucial for certain converter uses of nonwoven fabrics, such as hygiene and medical applications Historically, the level of microbial contamination of natural fibers, such as cotton, have not been quantified and little consideration has been given to synthetics

3 Research Objectives Measure the microbial burden on fibers and fabrics destined for use in nonwoven applications. Assess microbial cross-contamination when running cotton and synthetic fibers on the same line. Measure amount and composition of suspended solids in effluents collected during hydroentanglement.

4 Fiber Types Utilized in this Study Natural Fibers Cotton Mid-South new harvest Mid-South 5 yr. warehouse bale Mechanically cleaned greige cotton (Mid-South new harvest) Scoured and bleached cotton Synthetic Fibers Rayon Polyester Polypropylene

5 SRRC Opening Line Hopper, superior opener, fine cleaner, distribution/reserve, chute

6 Nonwoven Line Card Crosrol Mark IV Cotton Tandem Card

7 Crosslapper and Needlepunch Number of crosslaps depending on fiber type

8 Needlepunch Cotton Fabric Fabric weight utilized in this study ~ 70 g m -2

9 Hydroentanglement 3 pressure heads: 1 wet-out (50 bar), 2 high-pressure (125 bar)

10 Sampling Workflow

11 Microbial Sampling Protocols Reliable range for heterotrophic spread plate count - colony forming units (CFU) CFU per plate Fibers CFU g -1 or CFU cm -2 (based on specific fabric weight) Fabrics CFU g -1 or CFU cm -2 H-E Effluents CFU ml -1 ASTM D : Standard Practice for Microbial Colony Counts from Waters Analyzed by Plating Methods

12 Pharmacopeia Acceptance Criteria Bacterial Microbial Limits Total aerobic microbial counts (TAMC) 10 2 CFU g -1 or CFU ml -1 Fungal Microbial Limits Total yeasts/molds counts (TYMC) 10 1 CFU g -1 or CFU ml -1 Pharmacopeia: European ; United States USP <61>; Japanese JP 12

13 Pharmacopeia Acceptance Criteria Complete absence of specified microorganisms potentially pathogenic Escherichia coli oral Staphylococcus aureus oromucosal, gingival, cutaneous, nasal, auricular, vaginal Pseudomonas aeruginosa oromucosal, gingival, cutaneous, nasal, auricular, vaginal Candida albicans - vaginal Pharmacopeia: European ; United States USP <62>; Japanese JP 12

14 Total Aerobic Microbial Counts during Nonwoven Processing TAMC (CFU g -1 ) Fiber Type Fibers NP Fabric H-E Fabric Cotton - greige, new < 20 Cotton greige, old bale Cotton - greige, mechanically cleaned 7217 < 20 na Cotton scoured & bleached < 20 < 20 < 20 Polyester 0 < 20 < 20 Polypropylene 0 < 20 < 20 Rayon < 20 < 20 0

15 Total Aerobic Microbial Counts during Nonwoven Processing

16 Total Aerobic Microbial Counts in H-E Effluents - Sampling

17 Total Aerobic Microbial Counts in H-E Effluents

18 Total Aerobic Microbial Counts in H-E Effluents TAMC H-E Fabric Supply Water (CFU ml -1 ) Baseline Wash (CFU ml -1 ) Fabric Effluent (CFU ml -1 ) H-E Fabric (CFU g -1 ) Cotton - greige, new < 20 < < 20 Cotton - greige, mechanically cleaned Cotton scoured & bleached 0 < < 20 < 20 < 20 < 20 < 20 Polyester < < 20 < 20 Polypropylene 0 < < 20 Rayon 0 <

19 Bacterial Counts on New Harvest Greige Cotton Fibers and Nonwoven Fabrics Representative plate counts indicating microbial colonies isolated from fibers and fabrics on nutrient agar at ~24 hr Loose fibers NP Fabric H-E Fabric

20 Yeasts / Molds and Hemolytic Microorganisms Total yeasts/molds counts Newly harvested greige cotton 9,867 CFU g-1 All other cotton and synthetic fibers and fabrics Below the reliable limit of detection (ASTM D5465) Hemolysis All fibers and fabrics Below the reliable limit of detection (ASTM D5465) No hemolysis observed on blood agar plates

21 Microbial Cross-Contamination Not Measureable in NP Fabrics

22 Bacterial Counts on Common Surfaces Fiber CFU cm -2 based on fabric weight of 70 g m -2 Rusin et al., 1998; Donofrio et al., 2012; Gerba et al., 2012

23 Suspended Solids in H-E Effluents Measure amount and composition of suspended solids in effluents collected during hydroentanglement Sampling points same as for microbial enumeration Supply water H-E effluents pre-production baseline wash H-E effluents production run with fabric Standard for the Examination of Water and Wastewater Solids; Am. Pub. Health Assoc., Am. Water Works Assoc. Water Environ. Fed.

24 Suspended Solids in H-E Effluents Solids > 0.3 mm Standard for the Examination of Water and Wastewater Solids; Am. Pub. Health Assoc., Am. Water Works Assoc. Water Environ. Fed.

25 Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) Spectroscopy Suspended solids Chemically scoured H-E roll goods H-E roll goods 9.1 MJ kg -1 H-E roll goods 4.8 MJ kg -1 Greige cotton fibers

26 Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) Spectroscopy C-C stretch from - CH 2 -, epicuticular waxes Suspended solids Chemically scoured H-E roll goods H-E roll goods 9.1 MJ kg -1 H-E roll goods 4.8 MJ kg -1 Greige cotton fibers

27 Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) Spectroscopy

28 Attenuated Total Reflectance Fourier Transform Infrared (AT-FTIR) Spectroscopy C-C stretch from - CH 2 -, applied finish (oil, wax, etc.)

29 Conclusions H-E processing on SRRC pilot scale system reduces microbial burden to levels that meet Pharmacopeia acceptance criteria for TAMC and TYMC. Microbial cross-contamination did not occur when running cotton and synthetic fibers on the same production line. Cotton suspended solids composition primarily cell wall (cellulose, pectin) and wax.

30 Conclusions Mechanical cleaning of greige cotton reduces microbial populations. Storage time reduces microbial populations presumably Nutrient depletion (leaf, stem, etc.) Increase in bale moisture content causing a break in dormancy followed by microbial death

31 Acknowledgements Jan O Regan & Julie Clemmons Cotton Inc. CRADA partners Anthony De Lucca USDA-ARS-SRRC, Food & Feed Safety Brian Condon USDA-ARS-SRRC, Cotton Chemistry & Utilization, RL Linghe Zeng USDA-ARS-MSA, Crop Genetics Richard Byler USDA-ARS-MSA, Cotton Ginning Michael Reynolds & Hiram Allen USDA-ARS-SRRC, Cotton Chemistry & Utilization Kelley Williams & Mary Lovisa USDA-ARS-SRRC, Food & Feed Safety Michael Santiago Cintron USDA-ARS-SRRC, Cotton Structure & Quality Crista Madison USDA-ARS-SRRC, Cotton Chemistry & Utilization

32 THANK YOU! For more information about this study, contact Doug Hinchliffe at or Julie Clemmons at