The best solution is to ensure that your people are properly recording lot numbers and quantities.
The best electronic traceability system in the world is worthless if the people that are entering the data are not entering the correct data.
We have a fairly robust system where I work, but the results of our traceability system exercises show that now and again, we can't account for 100% of what we are trying to trace. So, I have put in place daily reconciliations of what the people on the floor document that they are putting into inventory and what actually is input into the stock management program.
As with all things, it really comes down to training your people so that they understand why it is so important to properly record information that deals with traceability.
If you choose to use Excel or Access, you have to limit the inputs by your people so that they are all the same by using drop downs or other data validation.
98760 Chocolate Bars and Brand X Chocolate Bars may be the same thing, but if you are doing a quick Find in Excel or are doing a quick filter in Access, they are not the same thing.
I know these are really general answers to your questions, so if you can provide some more specifics about what you are actually trying to trace, it might give people more insight to better answer your questions.
Marshall