CAGE PROCESSING in Animal Facilities - Felasa

7.3.1 WashingThe washing performance is assessed according to DIN 10511. The water bottles are contaminated directlywith test soiling. No extra test strips are needed. The relevant test number of items as well as the number ofthe wash cycles are indicated in table 7-2. The assessment is done on a visual basis.7.3.1.1 Producing the test soilingThe test soiling for contamination is made of reconstituted skimmed milk. For producing 100 ml of reconstitutedskimmed milk, 10 g skimmed milk powder is mixed with 100 ml distilled water. The mixture must be stirredvigorously before being steam sterilised for 5 minutes at 121 °C. For extra good adhesion, 13 g celluloseshould be added before sterilising.Table 7-3Chemicalspray-dried skimmed milk powdercellulose (microcrystalline for thin-layer chromatography)Source of supplypharmacyFLUKA chemicals catalogue, CH-Buchs7.3.1.2 Applying the test soilingA water bottle should be half-filled with test soiling and be emptied by giving it a rotation in a tilted position, sothe entire inside of the bottle is wet with test soiling. For wetting the bottle rim, it is recommended to dip the rim1 cm deep into the test soiling. The drying process takes 2 hours altogether with the bottles being first placedupside down in a bottle crate and turned over after an hour.The assessment is done visually and differentiates between clean and soiled bottles (please refer to figuresbelow). Acceptance criteria: All test bottles must be visually clean.Figure 7-7 Contaminated test bottle Figure 7-8 Still soiled test bottle Figure 7-9 Clean test bottle7.3.2 DecontaminationWater bottles do not get soiled and contaminated as much as cages and other items for processing do (e.g.with excrement, urea, etc.). Therefore, the decontamination of water bottles is not equally relevant. Although itis generally possible to check water bottles for decontamination, it needs a very complex procedure. The reasonis, that there are no standardisable test strips, and each bottle type would have to undergo an individualprocedure. It is therefore recommended by the working group to sterilise water bottles whenever a hygienicstandardisation of the processing procedure for water bottles is required. This approach is also common practice.54Cage Processing in Animal Facilities · 4th issue · 2013