This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Microbiology
[{'content': 'Staphylococcal food poisoning includes the following feature - \nSelect and explain. \nA. Incubation period of 24 hrs., B. Requires immediate antibiotics, C. Common with dairy products, D. Heat labile enterotoxin', 'role': 'user'}, {'content': "Answer: C \nExplanation: Staph aureus food poisoning\n\nS. aureus food poisoning results from inoculation of 'toxin-producing S. aureus' into food by colonized food handlers.\n\n\nIt is caused by preformed enterotoxin. This enterotoxin is heat stable. It is a superantigen-like toxic shock syndrome toxin.\nEight antigenic types of enterotoxins are currently known A, B, C1, C2, C3, D, E and H. Type A is responsible for most of the cases.\nThe toxin stimulates the vagus nerve and vomiting center of brain. It acts directly on the autonomic nervous system rather than on gastrointestinal mucosa.\nThe toxin is antigenic and neutralized by the specific antitoxin.\n\n\nEnterotoxins are produced when S. aureus grows on carbohydrate and protein foods.\n\n\nStaphylococcal food poisoning occurs after eating meat and fish, or milk and milk products as custards or potato salad.\nStaph food poisoning is characterized by nausea and vomiting within 1-6 hours\xa0of ingestion. Diarrhea, hypotension, and dehydration may also occur. Fever is unusual.\nDiagnosis can be established by demonstration of bacteria or documentation of enterotoxin in the implicated food.\nStaphylococcal food poisoning is self-limited illness, symptoms generally resolve within 8 to 10 hrs. Treatments are symptomatic only, no antibiotic is required.", 'role': 'assistant'}]