May, 2009

Composition of natural biofilms in household washin g machines

Düsseldorf, 12.05.2009 44th International Detergency Conference

Caroline Amberg, Daniel Fäh, Felix Freyempa testmaterials ag, St. Gallen, Switzerland

May, 2009

Content

• Laundry Hygiene / Biofilm • Trends in the Laundry field• Biofilm in white goods / washing

machines• Medical / economic relevance • New programs / products

• Standards and guidelines• Laundry hygiene• Biofilm

• Composition of natural biofilms in household washing machines

• Project activities of empa testmaterials ag

• Composition of natural biofilms• Conclusions

May, 2009

Laundry Hygiene / Biofilm: Trends in the laundry fi eld

• Washing temperatures decrease• Synthetic textiles• Sustainability• Energy labelling

• Water consumption decreases• Sustainability• Energy labelling

• Extended use of wash detergents without bleach(color powder, liquids)

• microbial resistance against antibiotics and disinfectants (also bleach?)

• Potential Pathogens are present on laundry items • Social changes (lifestyle, household)

Assumption: Laundry performance regarding hygiene may have decreased and will change further

May, 2009

Decreased hygiene performance may lead to:• Short term: Insufficient microbial reduction

on textiles and washing machine• Potential health risk

• Long term: biofilm formation• Odor of the washing machine• Recomposition of microorganisms on

textiles (odor of freshly washed textiles)• Biocorrosion• Potential health risk

Laundry Hygiene / Biofilm: Trends in the laundry field

poor scientific proofs of deseases related to insufficientwashing hygiene / biofilm formation in washing machines.Theoretical risk versus real risk

May, 2009

Laundry Hygiene / Biofilm: Biofilm in white goods / washing machines

Some ‚real‘ examples of biofilm in washing machines:• Two class action law suits related to

biofilm formation in washing machines • Allergic reactions / dermatitis caused by

mold spores from washing machines (Osaka City Institute of Public Health and Environmental Sciences)

• Other examples

May, 2009

Laundry Hygiene / Biofilm: Medical / economic relevance of biofilm

• Other problem fields where biofilm causes high costs are paper production, water systems, food processing plants, medicine etc.

• Medicine: implants like heart valves, catheters

• Biofilm-associated diseases: chronical diseases, cystic fibrosis, etc.

Biofilms are from medical and economic relevance

paper production

Staph. aureus on catheter

May, 2009

Laundry Hygiene / Biofilm: market ‚reactions‘

• Washing machines (some examples)• Steam (whirlpool, LG)• Silver-ions (Samsung)• heat (Miele)• Ultrasound (sharp, sanyo)• Ozone• Soil level sensor (Schulthess)

• Detergents / chemicals (some examples)• Wasch-Maschinen Pflegereiniger (Dr.

Beckmann)• Affresh™ Washing Machine Cleaner

(Whirlpool)• Oust Dishwasher and Washing

Machine Cleaner

No standard method to test efficiency of biofilm - removal of the newly developed programs and chemicals exist

May, 2009

Standards and guidelines: Disinfectants / Laundry Hygiene

Standards :In vitro Tests: • EST EN 1276 (disinfectants and antiseptica,

suspension tests)• ASTM E 2274 (normal washers)• ASTM E 2406-04 (High Efficiency washers)

Guidelines:• DGHM-Guideline (chemothermal Laundry

disinfection)• RKI-Guidelines (List of Disinfectants and

disinfecting techniques)• Determination of the Microbiocidal Effect of Laundry

Detergents‘ (Block et al. (2001) ) (Based on DGHM-Guideline: difference: Without blood, was developed by Henkel and TNO)

• DISS/TSS-13 EPA (Laundry additives-disinfection and sanitization)

May, 2009

Standards and guidelines: Biofilm

Standards :ASTM E 1427-00: (chemicals for biofilm-prevention, inactivation and removal, collection of possible growth methods and biofilm quantification methods)ASTM E 2562 – 07: (Growth parameter for a Ps. aeruginosa Biofilm under high shear, run time 48 h)ASTM E 2196 – 02: (as ASTM E 2562 but continous stirred flow reactor, ‚repeatable‘ Pseudomonas aeruginosa biofilm, not a mature biofilm (48 h run time))prEN ISO 14698-3 (1999): Effectiveness of disinfection- and cleaning processes of surfaces in clean rooms.

No guideline exists that could be adapted to washing machine biofilms

May, 2009

Washing machine biofilms: Project activities empa testmaterials ag

Development of methods to test the efficacy of biofilm removal / prevention of washing processes in household washing machines (funded by the swiss federal comission of technology and innovation KTI)

• Microorganisms in natural washing machine biofilms

• Growth of reproducible and repeatable model-Biofilms with three different testmicro-organisms (gram+, gram-, yeast)

• Kit for a fast, user-friendly, semiquantitative characterization of the efficacy of biofilm removal

May, 2009

Washing machine biofilms: Project activities empa testmaterials ag

Method to determine the efficiency of biofilm removal

relevant testgerms?Analysis of natural washing machine biofilms

Production of reproducible biofilms with the following requirements:• ‚standardized‘• resistant to temperature

and detergent• attachment firm enough• applicable in-house, no

special lab required

Test Kit

May, 2009

Composition of natural biofilms: find relevant testmicroorganisms

• Examination of 8 washing machines from the United States, Asia and Europe

• Interested in cultivable, fast-growing, biofilm-forming microorganisms on different ‚critical‘ locations

• Sampling by wet / dry swabbing

Limitations:• Real composition is not known (FISH, DNA-

extraction and cloning, RFLP, other molecularbiological approaches)

• Real distribution of the cultivated germs• Metabolism relies on annother germs product• 99 % of the germs are non-cultivable

May, 2009

Composition of natural Biofilms: groups of identifi ed microorganisms

May, 2009

Composition of natural biofilms: risk class 2 membe rs

• 133 isolates, 68 different species• Around ¼ of the isolates belong to Risk class 2• Examples:

• Stenotrophomonas maltophila• Trichosporon sp.• Serratia marcescens• Citrobacter braakii• Klebsiella pneumoniae• Pseudomonas aeruginosa• Enterobacter cloacae• Ochrobacter anthropii• Burkholderia cepacia• Mold sporesPseudomonas sp.

May, 2009

Composition of natural biofilms: general results

• Different species in washing machine biofilms (regions)• Soil, climate, washing habits, water• Asian machines: more yeasts• US-machine: more mold

• Distribution of species on the different locations was not surprising

• Potential pathogens are present in all sampled machines • ‚real‘ prevalence in the biofilm is not known• The recomposition on laundry items is possible

More investigations are necessary to assess the relevance for the consumer and manufacturer (risk, odor, biocorrosion)

May, 2009

Conclusions

• Washing habits are changing• Some problems as odor and biocorrosion

occur more often• Lack of scientific studies concerning biofilms in

washing machines• Washing machine manufacturers and

chemical industry are developing new programs / products that claim the prevention of biofilm or cleaning of washing machine

• No real standard exists to measure the efficiency of biofilm removal in washing machines

• The efficiency of programs and products can not be assessed so far

May, 2009

Conclusions

• More investigations are necessary to know more about the ‚real‘ relevance for the consumer and manufacturers

• Focus should be put on:• Removal of biofilm: how is it properly determined?• Cleaning the biofilm = removal of organic material or

just killing the living cells?• How fast can a rebuild-up occur after cleaning with a

specific program / chemical component?• Prevalence of microorganisms in washing machine

biofilms• What is the most important consequence of the

biofilm? (odor of textile and washing machine, biocorrosion, health risk?)

• Interactions between biofilm in the machine and textiles (redeposition)

The novel method is a future tool to answer some of the questions and help to assess the efficiency of biofilm removal of new programs and products

May, 2009

Thank you for your attention!