I'd strongly disagree with that. TPC, yeast, and mold are more indicators of storage/transport conditions (ie did the materials get wet at some point) and general quality, but have very little to do with organisms of public health concern. Coliforms and salmonella sp. are *the* reasons for kill steps in chocolate making processes, and as such are the organisms of concern to be targeted for enumeration. It is those that one needs to concern themselves with.
Steam sterilization of nibs in commercial roasting operations is not an uncommon thing to do.
I will agree with you on the fact that total plate counts, yeast and mold are not indicators of coliforms or salmonella presence.
Guusb above asked about sterilising nibs.
I have been looking at options for sterilisation on the bean processing line we are building. Suppliers strongly suggest installing a sterilisation step in the process as this is very common practice in industrial applications, especially where the the product is sold on to other industrial customers and requires very low TPC results.
In whole bean roasting this is achieved by injection of steam into steriliser before roaster and requires quite large steam generation capacity.
I have looked at results of our micro testing over last few years, and TPC on beans range from 3x10^2 to 4-5x10^6, in cocoa liquor we have never gone over 8x10^3 and most results are below 1x10^3. Australian standards for finished chocolate require less than 1x10^4 and we have never had finished product at more than half of this level.
We are not selling any product to other industrial customers and looking at low probability of large salmonella contamination on beans and even lower chance of this contamination surviving roasting and grinding process we have decided not to install any additional sterilisation steps in our process.
I have left a space for this just in case things change.