> Indeed past experience confirm that you can ge the dairy rich
> decorated cake and when done just allowing it to stand in ambient
> overnight...


..>I don't understand this
That is reasonable
You had never been a baker but presumably just academician
......therrefore you never had first hand experience in cases where
occasional violations of HACCP rules works...

>Pickles are a good example of foods with high
..>water activity that can safely be stored at room temp. The
combinations
..>of pH, water activity, preservatives and processing are the
determinants.

Pickes?....bakers and pastry cooks don't deal with such items.... .
Normally bakers don't add any preservatives in cake icings nor have to
use most of the time high processing temperatures ..( for example in
boiled icings)
Its common for these tradesmen to make icings at room temperatures...
In addition to that pH is not an issue with cake frosting materials
either


...