Final answer:
The most likely cause of the patient's illness is staphylococcal food poisoning.
Step-by-step explanation:
Based on the symptoms described, the most likely cause of the patient's illness is staphylococcal food poisoning. Staphylococcal food poisoning occurs when Staphylococcus aureus produces enterotoxins in food, resulting in symptoms such as nausea, vomiting, diarrhea, and cramping within 1 to 6 hours of ingestion.
It is important to note that staphylococcal food poisoning is different from bacterial infections like shigellosis, cholera, E. coli gastroenteritis, and salmonellosis, which can also cause gastrointestinal symptoms.