1. ## 3 log reduction

Can someone help me calculate a 3 log reduction of microbial growth for efficacy studied of cleaning agents

2. Originally Posted by northb
Can someone help me calculate a 3 log reduction of microbial growth for efficacy studied of cleaning agents
I'll have a go but currently your question makes little sense. Can you post the full question verbatim please?

3. I need to determine what a 3 log reduction is for a cleaning validation study I am performing. If I have a known concentration of organism per ml of innoculum, what log reduction would be required to achieve a 95% kill rate

Originally Posted by e^(i*pi)
I'll have a go but currently your question makes little sense. Can you post the full question verbatim please?

4. I'm afraid you will have to explain exactly what a "log reduction" is. I don't believe that is a standard math phrase.

5. ## 3 log reduction

"Log reduction" is a mathematical term (as is "log increase") used to show the relative number of live microbes eliminated from a surface by disinfecting or cleaning.

For example, a "5-log reduction" means lowering the number of microorganisms by 100,000-fold, that is, if a surface has 100,000 pathogenic microbes on it, a 5-log reduction would reduce the number of microorganisms to one.

Log Reductions

• 1 log reduction means the number of germs is 10 times smaller
• 2 log reduction means the number of germs is 100 times smaller
• 3 log reduction means the number of germs is 1000 times smaller
• 4 log reduction means the number of germs is 10,000 times smaller
• 5 log reduction means the number of germs is 100,000 times smaller
• 6 log reduction means the number of germs is 1,000,000 times smaller
• 7 log reduction means the number of germs is 10,000,000 times smaller