Abstract:

【Objective】The purpose was to study the effect of disinfectant acid calcium sulfate (ACS) on the killing of microorganisms, and to provide basic data and theoretical basis for disinfectant prevention and control of human and animal diseases.【Method】After incubating ACS with 3% lecithin and 5% Tween-80 as phosphate buffer neutralizer for a period of time, Escherichia coli, Staphylococcus aureus, Salmonellaand porcine reproductive and respiratory syndrome virus (PRRSV) were added respectively for a period of time, We spread the culture mixture with bacteria on nutrient agar plates and cultured at 37℃ biochemical incubator for 18-24 h, the mixture with virus was inoculated on the cell plates and incubate in 37℃ cell incubator for a certain period of time to evaluate the neutralizing effect of the neutralizer. The comparison settings and evaluation criteria were as follows: disinfectant mixed with bacterial suspension or virus suspension (group 1), the mixture of disinfectant and bacterial suspension or virus suspension was mixed with neutralizer (group 2), the mixture of neutralizer and disinfectant was mixed with bacterial suspension or virus suspension (group 3), the mixture of sterile hard water and bacterial suspension or virus suspension was mixed with neutralizer (group 4), the mixture of sterile hard water and bacterial suspension or virus suspension was mixed with PBS (group 5), sterile hard water mixed with PBS (group 6). The evaluation criteria of the neutralizer effect in the bacteria killing test were as follows: group 1 had a very small amount of bacterial growth or aseptic growth; group 2 had bacterial growth, which was significantly less than that of groups 3, 4, and 5, but more than the group 1; the number of bacteria in group 3, 4,5 was close to that of the positive control group, no bacterial growth in group 6. All three repeated tests met the above conditions, and the results were consistent, it was determined that the selected neutralizer and concentration were appropriate. The evaluation criteria of the neutralizer effect in the virus inactivation test were as follows: group 1 had very little virus growth or no virus growth; group 2 had virus growth and was significantly less than that of groups 3, 4, and 5, but more than group 1. The growth of viruses in groups 3, 4, and 5 was similar to the original inoculation; the cells in group 6 grew normally. The results of the three repeated tests were consistent, and it was determined that the selected neutralizer and concentration were appropriate. We used the suspension quantitative sterilization method and the method of determining the virus titer to evaluate the elimination effect of ACS on the above-mentioned bacteria and viruses. We diluted the ACS 200, 300, 400, 500, 600, and 700 times to interact with the above-mentioned bacteria or virus for different time and added neutralizer for neutralization, then spread the bacterial mixture on nutrient agar plates to evaluate the killing effect of ACS by calculating the number of colonies, and determined the virus titer in the virus mixture to evaluate the killing effect of ACS on the virus.【Result】 The selected neutralizer can effectively neutralize the residual effects of ACS 200-fold dilution on bacteria and viruses, and the neutralizer was non-toxic to bacteria, viruses and cells. When ACS interacted with the bacteria for 0 h, it was neutralized immediately. The sterilization rate ofEscherichia coli at the maximum dilution of 300 times was 100%, the sterilization rate of Staphylococcus aureusat the maximum dilution of 600 times was 100%, and when the maximum dilution was 700 times, the sterilization rate of Salmonella was 100%. When ACS was diluted to 700 times, it was neutralized one day or six days after treatment with the above bacteria, and the sterilization rate was 100%. In addition, when ACS was diluted to 200 times, it was neutralized 60 minutes after treatment with PRRSV, and no virus titer was detected.【Conclusion】 When ACS diluted 700 times withEscherichia coli,Staphylococcus aureus and Salmonella for one day or more, it can produce better killing effect; when ACS diluted 200 times with PRRSV for 60 minutes, it can completely kill the virus, which will provide strong data support for the selection of disinfectants in the farms and provide reference for the prevention and control of epidemic diseases.

Key words: acid calcium sulfate, microbial, neutralizing agent, killing effect