Bactericidal and virucidal efficacies of food additive grade calcium hydroxide under various concentrations, organic material conditions, exposure duration, and its stability

Abstract

Aim:This study aimed to evaluate the bactericidal and virucidal activity of food additive grade calcium hydroxide (FdCa(OH)2) under various concentrations, organic material conditions, and exposure duration including its stability.Materials and Methods:The FdCa(OH)2 powder as well as the 0.17% and 3% solutions were evaluated for bacteria and virus inactivating efficacies against Salmonella infantis (SI), Escherichia coli, Newcastle disease virus (NDV), and avian influenza virus (AIV), in the absence or presence of organic materials. In addition, the stability of FdCa(OH)2, was also examined using wet-dry conditions and under sunlight.Results:The FdCa(OH)2 powder could inactivate both NDV and AIV in the absence and presence of organic materials within a 3 min exposure period. The bactericidal efficacy using solution form revealed that 0.17% and 3% of FdCa(OH)2 could inactivate SI in the absence and presence of organic materials within 3 min of exposure. However, 3% of FdCa(OH)2 inactivated E. coli both with and without organic materials within 3min, while 0.17% required 5 min to be efficacious. The virucidal efficacy also showed that 0.17% FdCa(OH)2 could inactivate NDV in the absence and presence of organic materials within 10 min and 30 min, respectively. However, AIV inactivation was achieved within 30 sec under all conditions. In addition, under wet and dry conditions, FdCa(OH)2 powder demonstrated high efficacy when re-suspended at least 16 times for NDV and 7 times for AIV. Simultaneously, the FdCa(OH)2 powder retained its efficacy under the sunlight during up to 4 months for NDV and at least 6 months for AIV.Conclusion:The present study indicates that FdCa(OH)2 powder and solutions could inactivate SI, E. coli, NDV, and AIV while retaining good stability under challenging environmental conditions. Finally, the FdCa(OH)2 is safe for consumers because it is of food additive grade and can be useful as an alternative disinfectant, especially for biosecurity enhancement on and around poultry farms.

Farm use of calcium hydroxide as an effective barrier against pathogens

“…These results suggest that the disinfection effect resulting from the high alkalinity of Ca(OH) 2 lasted only approximately 2 weeks to 1 month under stand-by disinfection conditions. In another study, the pH and disinfection effect of Ca(OH) 2 powder decreased after alternating wet and dry conditions 14 , suggesting that the decrease in pH during the one month was due to environmental conditions. The fastest drop in pH in front of the barn may have been due to Ca(OH) 2 contact with livestock manure, as the CO 2 generated by heterotrophic microorganisms in manure can neutralize hydroxyl ions 15 .…”

Stability and Detection Limit of Avian Influenza, Newcastle Disease Virus, and African Horse Sickness Virus on Flinders Technology Associates Card by Conventional Polymerase Chain Reaction

“…After allantoic fluid harvesting at 3 days post-inoculation, stock viruses were aliquoted and kept at −80 • C until testing. Both viruses were titrated using chicken embryonic eggs, following the methods described by Ruenphet et al [34]. Additionally, the live attenuated African horse sickness vaccine serotype 1 (Onderstepoort biological product, Pretoria, South Africa) was dissolved following the manufacturer's recommendation.…”

Sensitivity of RNA viral nucleic acid-based detection of avian influenza virus, Newcastle disease virus, and African horse sickness virus on flinders technology associates card using conventional reverse-transcription polymerase chain reaction

“…After allantoic fluid harvesting at 3 days postinoculation, stock viruses were aliquoted and kept at −80°C until testing. Both viruses were titrated using chicken embryonic eggs following the methods described by Ruenphet et al [11].…”