Final answer:
The most effective action to improve a patient's oral intake after a surgery and with a wound infection is to refer the patient to a dietician for a tailored meal plan.
Step-by-step explanation:
The action by the nurse which will be most effective in improving the patient's oral intake is to make a referral to the dietician. A dietician can assess the patient's nutritional needs and preferences and provide a customized meal plan that appeals to the patient's tastes and meets their dietary requirements. This approach addresses the issue of the patient finding the current menu unappealing and helps ensure that they receive the necessary nutrients to recover from surgery and fight the wound infection.