Fresh Meat is a data file that's part of standard Apple DOS- or ProDOS-based Eamon adventures. The file stores all the details of the adventurer who is currently playing the story, or the one who most recently played it.
The Dungeon Design Manual describes how an adventurer moves through the file:
When a player embarks on an adventure, his character is taken from the CHARACTERS file, and its record in CHARACTERS is marked empty. Its name and CHARACTERS record number is recorded in a file named THE.ADVENTURER, and the player is prompted to insert the adventure disk into the disk drive. The character's attributes are put into the FRESH.MEAT file, and EAMON.NAME is opened to obtain the name of the adventure. The MAIN.HALL program then RUNs the program that has the same name as the adventure.
Once the adventure is over, control is returned to the Master diskette. If the character died, THE.ADVENTURER is deleted, & MAIN.HALL is run. If the character survived, he is replaced in the CHARACTERS file. The MAIN.PGM rewrites him into his own character record now.