CAGE PROCESSING in Animal Facilities - Felasa

the sanitization procedure is only verifiable by means of indicators and cannot be captured directly by processparameters like temperature or pressure. The sole process of room gassing will not be discussed in this context.4.6.1 Material lockThere are two relevant procedures for heat-sensitive products to cross a barrier via so-called locks: One is bybeing gassed with hydrogen peroxide (H 2O 2), the other is by being sprayed with peracetic acid (PAA). Specialcases like transferring items out of S3/S4 areas will not be part of the general discussion here, as these casesalways need to be examined individually. Below you will find characteristic examples of heat-sensitive productsfor the two presented sanitization procedures:• characteristic heat-sensitive products suited for both procedures: e.g. vacuum-packed, gamma-irradiatedlarge or small feed or bedding bags,• characteristic heat-sensitive products for H 2O 2use only: e.g. power tools, computers, microscopes, measuringdevices, fan units, cage changing stations, microbiological safety work benches, ventilated animalhousing cabinets, bedding disposal stations,• characteristic heat-sensitive products for PAA use only: simple, corrosion-resistant tools, other productswith a solid PAA-resistant surface,• transport containers to bring animals into a barrier area.Please note:Due to a material-related heavy absorption, gassing plastic cages with H 2O 2can cause problems with the slowrelease of the gas. The GV-SOLAS thus recommends to refrain from gassing plastic cages in order to preventanimals from the risk of increased H O exposure.2 24.6.2 Requirements of processing procedures by means of H 2O 2Below you will find a description of effect and suitability of vaporised H 2O 2for reducing organisms in locks aswell as its limitations of use that need to be examined more closely.Sanitization with H 2O 2H 2O 2is a strong oxidant with efficient inactivating abilities for microorganisms like spores, bacteria, viruses, andfungi. In liquid and vaporised state, H 2O 2is colourless and odourless. For information on safe handling of H 2O 2in liquid and vaporised state, please refer to the data sheets on occupational safety (please note the safety datasheets of the manufacturers). Over time H 2O 2in liquid state can become increasingly concentrated due to theevaporation of the H 2O. It can therefore easily cause chemical burns (skin contact) and material damage (corrosion).Materials like pulp, textiles, or bedding (wood) are highly prone to absorbing H 2O 2.Due to chemical reactions,the flashpoint of these materials is lowered. Therefore, these products should not be treated with H 2O 2.Gassing with H 2O 2offers a major advantage to Chlorine Dioxide or Formaldehyde as it produces no visible ortoxic residues. Due to its instability (thermally induced decomposition, light-induced decomposition, catalyticdecomposition), it splits back into H 2O and O 2after the gassing procedure is finished. Furthermore, a gassingwith H 2O 2can be done at room temperature and atmospheric pressure. Thus, no extra pressure container isneeded and the items to be gassed are not exposed to a critical temperature and pressure level.Currently, the common maximum allowable concentration (MAC) is MAC H2O2= 1.0 ppm. Under discussion is avalue of 0.5 ppm. (Please consult the laws and regulations of your respective country/EU standards.)Limitations of use that need to be examined closelyBesides the stated lowering of the flash point, time is always a crucial factor due to the slow release of theH 2O 2from the materials mentioned above. Absorption is not the only principal limitation to be considered here.There are also materials like nylon, rubber, or natural rubber (e.g. flooring) that suffer damages from H 2O 2gassing.It needs to be clarified individually if a material is resistant to H 2O 2. The surface of the items to be gassedmust be clean, dry, and non porous. Gassing heavily soiled and porous surfaces should be avoided.32Cage Processing in Animal Facilities · 4th issue · 2013