This depends on your autonomy. They should ideally be decided upon by your food safety and quality management team. You might want to include things on "right first time", microbiological results, complaints, audit results etc. Often your objective measures link back to verification measures for your HACCP. The key thing is they should be SMART, ie specific, measurable, agreed, realistic and timebound. (Sometimes people use different words to spell the same thing but the important thing is that they objectives should be ones you can really pin down that ideally have a number that isn't a "woolly" judgement thing and you should agree how to measure them.)
You may find though that you have some objectives imposed upon you. Nothing like producing for a retailer to get some objectives! Now of course these should be agreed with you but we know how retailers work! Generally, it's not open to discussion unless you have a very good relationship.
Last thing I'd say when setting objectives is the "realistic" is important. Look at where you are now before setting some pie in the sky target. Think about "what would a good result be?" and set your aim for the year at a stretch but not impossible target. If you want to get to 10 CPMU and you're at 100 for example though, set an interim target first. You're not going to reduce complaints by 90% in a year but 20% is acheivable, you might decide 30% is possible if you all work hard at it so your first year target might be to get to 70 CPMU and that would be a real result, however, if you aim for 10 and get 70, people might be disheartened unfairly. It is also sometimes possible to convince retailers to go for an interim target and it manages their expectations if you have a factory which really needs to change and improve. If they're not expecting results in a year, they won't be on your back when you don't achieve them and, in fact, may be more pleased at what results you do get.
Also it's important to review your objectives regularly and feed back to the teams on how you're doing. I'm a strong believer in sending out a positive message when there is one (even if it's a small positive sometimes) so if your complaints have dropped by 5% in two months, shout about it! Even if deep down you think "we've got a long way to go..." success and positivity breads success and interest! Also it's a chance for a sense check of "are we on track?" so you can change your tactics if your expected results aren't materialising.
