911. Mixing People and Giardia Infected Dog Dishes in the Dishwater

In this episode of Risky or Not, Professors Ben Chapman and Don Chaffner tackle a surprisingly complex question: is it risky to wash human dishes and dog dishes from dogs infected with Giardia in the same dishwasher? The query, submitted by listener Zach, reveals that all three of his dogs have Giardia, a parasitic infection often called 'beaver fever' due to its transmission through contaminated water. The hosts clarify that while Giardia is a concern for dogs—causing diarrhea and fatality in young or immunocompromised animals—it rarely poses a zoonotic risk to humans because the strains affecting dogs differ from those infecting people. They emphasize that the dishwasher’s high-temperature sanitize cycle, which can reach over 185°F, effectively kills Giardia cysts, and that the dilution from a full wash cycle further reduces any risk. The hosts also recommend using an inexpensive infrared thermometer (around $20) to verify the sanitize cycle’s effectiveness, promoting a science-backed approach to household hygiene. The episode concludes with a playful, repetitive reminder about the omnipresence of bacteria—especially Salmonella—while reinforcing that everyday risks are often far lower than perceived.