It is possible to get the keys to these codes by contacting the processor and asking how to decipher the dating code for specific product lines. Over time, readers have been doing this and the code keys below are the ones that have been sent to me. Obviously, they are only a few of the many, many products that use closed dating and I hope that future readers will continue to send these codes in as they are gleaned from the processors. Frankly, when it comes to the potential dozens of products that would require deciphering their packing codes the entire process is a major nuisance. While it is better to have an encoded date than not to have one at all, it would be far better if processors would just use clear open dating and (best used by) so we wouldn't have to carry a book of code keys like covert agents every time we go to the grocery. Should you happen to call a processor customer service number you might tell them this in an effort to encourage them. Before I list specific manufacturers there is one fairly widely used code key that may be useful.