rare steak? not sure, but raw meat can be bought in tons from the old lady by the guild. If it's for power juice, not really worth it I'd say as theres no real way to quickly make rare steaks. It'd be simpler to farm gypceros for power extracts while your cats cook droves of well done steak :D (mega juice ftw).
As for bitterbugs... No faster way i can think of to get them than low rank gathering quests :/.