Sterility assurance level (SAL) is a microbiology process that describes the probability of a single unit of being non-sterile after subjected to sterilization. Microbiologists stated that it’s impossible to prove that all organisms are eliminated. The reasons behind are as follows: organisms could be present yet undetectable and/or not incubated in their preferred environment. Probably, their existence has not been discovered yet. Hence this system is used. SAL is like an intelligent guess that all organisms are killed off after being sterilized. No wonder that medical device manufacturers used this procedure for their products.
Manufacturers designed their sterilization processes with very low SAL. This means that one in a million of their devices are considered non-sterile. A very high SAL means high probability of the sterilization process efficiency in killing organisms. The recommended survival probability for organisms set on a sterilized device is a SAL of 10-6. This level is also used on the whole microbial population contained in a device. A 10-1 log reduction means that 90% of the microbial group is reduced. The more this reduction rate is used, the higher reduction rate. So the experts try to achieve a 6 log (10-6) reduction to deduct a million of microbes close to zero.Read more about sterile compounding methods .
Control is achieved in the aseptic process by using sterile components; both inside and outside of the said process. IV bags, vials and ampoules have undergone aseptic processing. Medical manufacturers used them in their compounded sterilized products. Take note that prior to the development of Advanced Aseptic Compounding of the CTG, the exterior of these devices were not sterilized. At that time, there are no known ways to effectively decontaminate the external surfaces of those devices. This process cannot be repeated also.
Consistent decontamination process was provided by the MIC-EDU through its Advanced Aseptic Compounding technology. The process is repeatable to decontaminate both the exterior and interior surfaces of a device. A 10-6 reduction rate is also used in this system. Each reduction load utilized chemical indicators to check that decontamination is effectively done. The US FDA has a Medical Device Reporting Program or MedWatch, to determine if there is an increased infection of a medical product. MedWatch checks whether those devices labeled with “sterile” but don’t have a SAL of 10-6 level. Medical devices checked include sterilization-sensitive types, combination types, and cell or tissue-based types.
Sterility Assurance Level (SAL) has helped in determining safe medical products through the years. But it’s not perfect. Still many medical companies used it as a reliable system for device decontamination. To date, no established relationship between specific SAL rates and product safety intended for use in the actual environment. However, indicators like the SAL of 10-3 to 10-6 may provide a likelihood of adequate assurance against medical device infections. Medical manufacturers continue to adhere to these standards, until a new and more effective one comes along. When it does, improvements are expected. Still, additional researches are being done; in a hope that the detection rate of infections will be greatly improved in the near future.