an investigation of domestic laundry in europe - habits ... - SIFO

Hygiene effects of laundry processes in Europe 99quality of the most common washing processes in Greece, Norway and theNetherlands is more or less comparable. The reduction on the diaper samplevaried between 3 and 5.5 log units. About log 1.9 to 4.4 micro-organisms percm 2 remained after washing. The results from the Spanish washing processesseem to be very different from the other European countries. Only log 0.6 andlog 2 micro-organisms per cm 2 remained on a washed diaper. This indicates ahigher reduction level. The tests showed that the hygienic quality depends onthe washing temperature and the presence of bleaching agents in the detergentas well as on the interaction between these factors. This is confirmed by anadditional test. Almost all micro-organisms were removed from the laundrysamples in a 95°C programme using a detergent containing bleach.An interesting question is how these results compare to the hygienic quality ofevery day clean laundry. The hygienic quality is evaluated directly after washingwhile the samples are still wet. On clean, dry laundry the Total PlateCount is considerably lower. Samples taken from clean laundry in a cupboardshow that the average count is about log 2.5 CFU /4.7cm 2 . Drying and ironingseem to have a positive effect on the amount of micro-organisms. One of themost interesting findings is that washing seems to spread micro-organismsrather than removing them. Sterile samples were very often contaminated withall kinds of bacteria. But the sterile samples are not the only indication ofcross-contamination and the spreading of micro-organisms. Spreading is alsofound among laundry items. For example, Enterobacteriaceae were foundonly on the unwashed diaper and dishcloth, but all other items were contaminatedafter washing.Another interesting outcome of this research is the increase in hygienic qualityof the laundry items achieved by adding an extra rinse to the washingprocess. This finding emerged when verifying the Spanish results. The Spanishhygiene level seems to be systematically higher than in the other Europeancountries. One explanation for this could be the extra rinse, which was addedto the wash cycle due to extensive foaming. In an additional experiment theeffect of an extra rinse was tested. The hygienic quality was improved bymore than 1 log unit.4.6.1 Evaluation of the test methodThe repeatability and validation of the method developed were evaluated inChapter 4.6.1 and 4.6.2 The results showed that the method seems to be repeatable,is valid and reflects common daily practice. However, before bringingthis method to the attention of standardisation bodies, research institutes,