You might consider prefixing other fields with an apostrophe to avoid them being misinterpreted as numbers or dates.

Unfortunately, even if you put an apostrophe on everything, problems remain:

- the apostrophes are non-standard and assure all other CSV-handling tools get the wrong, apostrophe-prefixed values

- Excel itself doesn't escape fields on output, so if someone loads your exported file into Excel, saves it and reloads it, the exploits come back

Excel is a quite frighteningly terrible tool for handling CSV.