CAGE PROCESSING in Animal Facilities - Felasa

configurations can thus require individual program cycles. The effectiveness of them should always be verifiedand each process should ideally be validated. When planning the machines, this needs to be taken into account.Cycle developmentThe process parameters of a cycle are adjusted to each lock and its load. The cycle development must be discussedwith the manufacturer of the generator. In order to avoid material damage, clearly visible condensationmust be averted. Please find below information on applications (e.g. electronic devices) and cycle-relevantparameters:• Humidity exceeding the saturation level must be avoided (verifiable with mirror / pane test). Room capacity,initial temperature and humidity must be considered.• The H 2O 2injection rate must be adjusted to the absorption rate of the chamber surface and load.• Surface temperature and volume of the items to be gassed influence the maximum allowable, condensation-freeH 2O 2concentration (too cold surfaces bear a higher condensation risk).• The warm H 2O 2air mixture should be streamed into free space (e.g. from above) in order to avoid directcontact with cold surfaces (e. g. walls and doors) resulting in condensation.• Computers and other electronic devices should be cleaned in advance (dust should be removed) and stayswitched on while being gassed (PC ventilators, fan units, etc. must be on).• Heavy condensation leads to increased H 2O 2consumption, differences in concentration distribution, increasedrisk of material damage, and a longer ventilation time.• Pre-heating long supply pipes can help avoid heavy condensation.Proof of efficacy / validationThe distribution of H 2O 2concentration is tested with a colour change of chemical indicators. A visual verificationthrough an inspection window can be made while the process is running.The microbiological efficacy is verified by use of biological indicators, usually H 2O 2gassing-suited spore strips(Geobacillus stearothermophilus) holding a population of 10 5 to 10 6 . When agreed upon with the operator,other organisms (e.g. Bacillus subtilis, Enterococcus faecium) can be used for verification, too. At least six ofthese biological indicators per m³ spatial volume must be placed at crucial points inside the lock.4.6.2.4 Processual documentationThe H 2O 2generator should automatically compile a cycle record. According to GLP, documenting is necessaryfor assigning a given item in the processing procedure to a recorded cycle. The cycle record should containinformation on temperature, relative humidity, air flow, operator, date, time, injection time and rate, ventilationtime, total consumption of H 2O 2per cycle phase, time sequence, selected gassing program, notices of malfunction,and release.4.6.3 Requirements of processing procedures by means of peracetic acidProcedures using peracetic acid (PAA) have become less important and are often replaced by H 2O 2procedures.Below you will find essential information on the effectiveness and suitability as well as limitation of PAAfor sanitization in locks.Sanitization with peracetic acidSanitization with PAA is a wet procedure that is only suited for items with a non porous surface. PAA is a highlyeffective disinfectant with highly oxidising characteristics. For a safe handling of PAA, please consult therespective work safety data sheets (please pay attention to the safety data sheets of the manufacturer). A lowconcentration of PAA (0.5 – 1.5 %) inactivates spores, bacteria, viruses, and fungi at a low temperature of 4 to20 °C.PAA in diluted solution consists of a balance of H 2O 2and acetic acid. Therefore, the limit levels of H 2O 2(1 ppm)and acetic acid (10 ppm) are of crucial interest. When there is no noticeable acetic acid odour, it is safe to saythat the air value limits are within normal range. If the ventilation is insufficient, however, visible residues canoccur.Cage Processing in Animal Facilities · 4th issue · 2013 35