Hot Chocolate Contamination

Hot chocolate from vending machines may contain Bacillus cereus capable of producing toxins that cause nausea and vomiting. This risk comes from the pooling of warm beverage in machine parts that cannot be adequately cleaned during routine flushing. B. cereus commonly occurs at low levels in dry milk, grains, rice, etc. The spores grow in warm, moist conditions giving rise to toxins which are unaffected by later reheating.

In one city, vending machines were examined following reports of illness about an hour after drinking the beverage. Seven of the 39 licensed machines were contaminated, and two had B. cereus levels high enough to cause illness.

Examiners concluded that the hot chocolate powder was the source of bacteria, but that the risk of illness occurred when machines had places where warm liquid could pool despite automatic rinse cycles or when operators disconnected part of the rinse cycle. It was noted that machines cleaned daily rather than weekly by the operators had no detectable B.cereus.

(Nelms J. Time to B. cereus about hot chocolate. Public Health Rep 1997;112(3):240-244.)

COMMENT: Chocolate drink powder per se is not regarded as a risk, but nurses should consider the possibility if symptomatic persons indicate having recently drunk hot chocolate from a machine. The nausea and vomiting are of short duration and not so serious for healthy persons so that these illnesses are likely underreported. …not that we need one more thing to fear. -J.O.