A deli worker sneezes into a tray of prepared potato salad and then it sits at room temperature for several hours before customers eat it. Later many customers experience rapid onset vomiting within 2–4 hours. Which pathogen and mechanism is most consistent with this outbreak?

• A. Staphylococcus aureus — infection from a food handler transferring bacteria that produced a heat-stable preformed toxin during improper holding.
• B. Clostridium botulinum — the quick onset and vomiting are hallmark signs of botulinum toxin from mayonnaise-based salads that were kept at room temperature.
• C. Listeria monocytogenes — an incubation period of 2–4 hours and vomiting predominant are classic features of listeriosis from deli salads.
• D. Norovirus — because sneezing always transmits norovirus and causes preformed toxins in salad that are heat-stable.

Answer: (A)