If your current systems are custom, heavily modified versions of packages or just old, you face a bigger challenge. You may need to replace the existing systems. Both ERP and MES vendors are now touting systems that can help you comply. Be aware that the FDA does not validate software products. Remember that software suppliers can only assist you in compliance. If a software salesperson says, "We're compliant," he or she does not understand the regulations and a red flag should go up.
The Age of Electronic Accountability: How to become compliant
By definition, Part 11 deals with computerized records. Your first step should be to contact the software vendors who provided you with any systems you currently have in your plant. Ask these vendors what they are doing about Part 11. Most vendors who serve the food industry are aware of the issues and are proactively addressing them. However, do not assume that what these vendors are doing is satisfactory. It is your responsibility to determine what you need for compliance given an interpretation (regulatory and/or legal guidance usually required) and to implement a compliance strategy that meets your specific needs. Not all vendors can meet your needs with standard products.