Which of the following is a pathogen that may be isolated from raw milk?

• A. Listeria monocytogenes
• B. Staphylococcal enterotoxins
• C. Shigella
• D. Tick-borne encephalitis virus

Answer: (C)

Raw milk can carry pathogens when it isn’t pasteurized, especially if hygiene during milking is poor and there is fecal contamination. Shigella is an enteric bacterium that is shed in feces and can contaminate milk through fecal contamination or contaminated hands and equipment. It is the type of organism that can be recovered from raw milk samples in investigations, signaling that contamination occurred and needs to be addressed. Pasteurization would kill Shigella, so identifying it in raw milk highlights the risk of consuming unpasteurized dairy. The other options either refer to toxins, a virus not typically associated with milk, or are true raw-milk hazards in general, but the organism that fits the notion of being isolated from raw milk in this context is Shigella.