There is no function which will look at a column of data and return you an appropriate datatype. This is something which Excel tries to do when it opens a CSV file and often does the 'wrong' thing - it's not easy.
If you feed your data through a Script Component within a dataflow, you will be able to redirect 'invalid' (based on your criteria) rows to a different output (and, from there, to a log file perhaps).
The absence of evidence is not evidence of absence.
Martin Rees
You can lead a horse to water, but a pencil must be lead.
Stan Laurel