Work out log reduction requirement instantly with clear inputs, formula shown and shareable results.
Required log reduction is log10 of initial load divided by acceptable load, plus a safety margin. Each log is a tenfold reduction, so going from 10^5 to 0.1 CFU/g needs 6 logs. Comparing that with the reduction the process actually delivers shows whether the process is adequate.
Log reduction
Required logs = log10(initial load / acceptable load) + safety margin
Survivors
Survivors = initial load x 10^(-delivered logs)
Required log reductions for pathogen control are set by regulation and must be validated for the specific product and process, not assumed.
Pasteurisation of milk gives 5 or more logs of vegetative pathogens; a chlorine wash on produce gives only 1-2 logs; high pressure processing 5-6 logs depending on product and pathogen.
To cover variability in initial load, process delivery and organism resistance. Regulations often specify the required reduction directly, and that specification takes precedence.