Objective:To screen out the disinfection procedure and disinfectant suitable for the actual production of specific pathogen free(SPF)chicken embryo eggs,so as to ensure the disinfection effect of specific pathogen free(SPF)chicken embryo eggs in vaccine production.Methods:This study compares the microbial counting methods of soaking,swabbing with cotton swabs and pouring after thin-film filtration for SPF chicken embryo eggs in a GMP production workshop,and selects the most suitable method for SPF chicken embryo egg microbial counting.Experi-mental groups A,B,and C use self-prepared concentrations of 1∶50 sporicidal agent dilution solution,1∶128 alka-line phenol salt dilution solution,and ready-to-use compound quaternary ammonium disinfectant(sterile),respec-tively,and follow the actual disinfection procedures in the workshop to disinfect and sample the surfaces of SPF chicken embryo eggs entering different cleanliness grades,while using sterile water instead of disinfectant as the control group.The average bactericidal rate is calculated by recording the number of colonies and monitoring the viability of chicken embryo cells using microbial culture,and the disinfection effect of the three disinfectants on SPF chicken embryo eggs is evaluated.Results:The comparison of the results from the three methods shows that the method of sampling SPF chicken embryo eggs by immersion and then counting the microbial colonies through membrane filtration is superior to the other two methods.The final cleaning rate of the control group,which used sterilized injection water to clean the SPF chicken embryo eggs,was 91.67％to 96.97％,while the final steriliza-tion rate of the experimental group,which used the above three disinfectants to disinfect the SPF chicken embryo eggs,was 100.00％.By comparing the cell counts of the experimental group and the control group,it was found that the live cell density of the control group was(6.03-6.25)× 105 cells·mL-1,and that of the experimental groups A-C was(6.08-6.17)× 105 cells·mL-1,(5.99-6.25)× 105 cells·mL-1,and(5.87-6.21)× 105 cells·mL-1 respectively;the cell viability of the control group was 90.33％to 91.35％,and that of the experi-mental groups A-C was 88.25％to 92.12％,89.45％to 93.59％,and 88.02％to 92.89％respectively.Through statistical analysis,it was found that the P values of all experimental groups compared with the control group were greater than 0.05,indicating no statistically significant difference.Conclusion:By comparing the dis-infection effects,cell density and cell viability of the three disinfectants and comprehensively considering factors such as cost and risk of the three disinfectants,1∶50 sporicide dilution,1∶128 alkaline phenolate dilution and ready-to-use compound quaternary ammonium salt disinfectant(sterile)can all be used for the daily surface disin-fection of SPF chicken embryo eggs in the production workshop.The selection of an appropriate disinfectant should be based on specific application scenarios and requirements.

Objective:To screen out the disinfection procedure and disinfectant suitable for the actual production of specific pathogen free(SPF)chicken embryo eggs,so as to ensure the disinfection effect of specific pathogen free(SPF)chicken embryo eggs in vaccine production.Methods:This study compares the microbial counting methods of soaking,swabbing with cotton swabs and pouring after thin-film filtration for SPF chicken embryo eggs in a GMP production workshop,and selects the most suitable method for SPF chicken embryo egg microbial counting.Experi-mental groups A,B,and C use self-prepared concentrations of 1∶50 sporicidal agent dilution solution,1∶128 alka-line phenol salt dilution solution,and ready-to-use compound quaternary ammonium disinfectant(sterile),respec-tively,and follow the actual disinfection procedures in the workshop to disinfect and sample the surfaces of SPF chicken embryo eggs entering different cleanliness grades,while using sterile water instead of disinfectant as the control group.The average bactericidal rate is calculated by recording the number of colonies and monitoring the viability of chicken embryo cells using microbial culture,and the disinfection effect of the three disinfectants on SPF chicken embryo eggs is evaluated.Results:The comparison of the results from the three methods shows that the method of sampling SPF chicken embryo eggs by immersion and then counting the microbial colonies through membrane filtration is superior to the other two methods.The final cleaning rate of the control group,which used sterilized injection water to clean the SPF chicken embryo eggs,was 91.67％to 96.97％,while the final steriliza-tion rate of the experimental group,which used the above three disinfectants to disinfect the SPF chicken embryo eggs,was 100.00％.By comparing the cell counts of the experimental group and the control group,it was found that the live cell density of the control group was(6.03-6.25)× 105 cells·mL-1,and that of the experimental groups A-C was(6.08-6.17)× 105 cells·mL-1,(5.99-6.25)× 105 cells·mL-1,and(5.87-6.21)× 105 cells·mL-1 respectively;the cell viability of the control group was 90.33％to 91.35％,and that of the experi-mental groups A-C was 88.25％to 92.12％,89.45％to 93.59％,and 88.02％to 92.89％respectively.Through statistical analysis,it was found that the P values of all experimental groups compared with the control group were greater than 0.05,indicating no statistically significant difference.Conclusion:By comparing the dis-infection effects,cell density and cell viability of the three disinfectants and comprehensively considering factors such as cost and risk of the three disinfectants,1∶50 sporicide dilution,1∶128 alkaline phenolate dilution and ready-to-use compound quaternary ammonium salt disinfectant(sterile)can all be used for the daily surface disin-fection of SPF chicken embryo eggs in the production workshop.The selection of an appropriate disinfectant should be based on specific application scenarios and requirements.

Objective:To study the quality and stability of commercial ready-to-use tryptone soya agar(TSA)after storing at 2-25 ℃ for different storage duration under dark condition in order to discuss a determination method of validity period for medium.Methods:Three consecutive batches of ready-to-use TSA medium from two manufac-turers were selected and stored at 2-25 ℃ under dark conditions for 30,90 and 180 days,respectively.The appearance,pH,medium suitability and sterility of the medium were tested.Results:The results of appearance,pH,suitability and sterility of TSA medium from two manufacturers for each batch under different storage duration all met the requirements of the Chinese Pharmacopoeia 2020 Volume IV on the quality control of medium.Conclusion:The TSA medium from two manufacturers all met the requirements when stored for 180 days at 2-25 ℃ under dark condition,indicating that the validity period of TSA medium from two manufacturers can reach 180 days.