I got a deer processed for me however I find the ground meat to be too lean for me. Is ok to defrost the meat, regrind it with more fat, and then freeze it again?
The interior of meat is naive to pathogens once you grind it youre exposing surface area to contamination which can double every 10 mins at body temp.
Other factors to consider is the heat generated while grinding and how it was froze was it slowly froze domestically or quick frozen and the packaging being freezer safe. It may be wrapped in plastic wrap that allows air in. Once frozen bacteria become dormant they dont die so can multiply again during the thawing process. Contamination can occur anywhere along the process during grinding and packing.
Ground meat needs to be cooked to 165 f or 75c to kill these bacteria That doesnt mean cook everything to 165 will make it food safe if the bacteria produce spores which can survive high and low extreme temps they can release toxins
Id suggest just thawing it as you are using it and adding fat in then whatever type of fat youd like evn bacon fat or cheese.
you can of course defrost it and cook it and refreeze though.
